BOSE AMPLUS 50, AMPLUS 100 Schematic

CONTENTS

Safety Information............................................................................................................................ 3

Electrostatic Discharge Sensitive (ESDS) Device Handling ........................................................ 4

Warranty Information....................................................................................................................... 4

Table 1. Amplifier Comparison Chart................................................................................................4

AmPlus™ 100 Amplifier Specifications ......................................................................................... 5

AmPlus 50 Amplifier Specifications............................................................................................... 6

AmPlus 100 Theory of Operation .............................................................................................. 7-10

AmPlus 50 Theory of Operation ................................................................................................... 11

Figure 1. AmPlus 100 Amplifier block diagram............................................................................... 12

Figure 2. AmPlus 50 Amplifier block diagram................................................................................. 13

AmPlus 100 Amplifier Controls................................................................................................ 14-15

AmPlus 50 Amplifier Controls....................................................................................................... 16

Disassembly/Assembly Procedures ....................................................................................... 17-18

Figure 3. AmPlus 100 Amplifier exploded view .............................................................................. 19

Figure 4. AmPlus 50 Amplifier exploded view ................................................................................ 20

AmPlus 100 Test Setup Parameters............................................................................................. 21

Table 2. AmPlus 100 Initial Switch Settings ................................................................................... 21

Table 3. AmPlus 100 Signal Inputs table........................................................................................ 21

Table 4. AmPlus 100 Signal Outputs table..................................................................................... 21

AmPlus 100 Test Procedures................................................................................................... 22-25

Table 5. Source Input to 70/100V Speaker Output test table ......................................................... 22

Table 6. Source Input to 4Ω Speaker Outputs ............................................................................... 24

Table 7. Bass Performance tests ................................................................................................... 24

AmPlus 50 Test Setup Parameters ............................................................................................... 26

Table 8. AmPlus 50 Initial Switch Settings ..................................................................................... 26

Table 9. AmPlus 50 Signal Inputs table.......................................................................................... 26

Table 10. AmPlus 50 Signal Outputs table ..................................................................................... 26

AmPlus 50 Test Procedures .....................................................................................................27-30

Table 11. Source Input to 70/100V Speaker Output test table ....................................................... 27

Table 12. Source Inputs to 4Ω Speaker Output ............................................................................. 29

Table 13. Bass Performance tests ................................................................................................. 29

Installation Diagram Notes:........................................................................................................... 31

Figure 5. AmPlus 100 Simple Mono Installation............................................................................. 32

Figure 6. AmPlus 100 Large Mono Installation using Mixer Feature.............................................. 33

Figure 7. AmPlus 100 70/100 Volt Mode/Model 1B Acoustimass

Figure 8. AmPlus 100 Installation with Two 70/100V Listening Zones........................................... 35

Figure 9. AmPlus 50 Simple Mono Installation............................................................................... 36

Part List Notes................................................................................................................................ 37

Main Part List AmPlus 100 Amplifier (see Figure 10) ................................................................. 38

Figure 10. AmPlus 100 Amplifier exploded view ............................................................................ 39

Main Part List AmPlus 50 Amplifier (see Figure 11).................................................................... 40

Figure 11. AmPlus 50 Amplifier exploded view .............................................................................. 41

Electrical Part List..................................................................................................................... 42-46

Resistors ................................................................................................................................... 42-43

Capacitors ................................................................................................................................. 43-44

Diodes ............................................................................................................................................ 44

Transistors...................................................................................................................................... 44

Integrated Circuits .......................................................................................................................... 45

Miscellaneous ........................................................................................................................... 45-46

Bass Module Installation......... 34

CONTENTS

This service manual has been updated with information from supplement 194101-S1. This affects part numbers for C610 and C611.

AmPlus™ 50 and 100 Accessory Notes....................................................................................... 47

Table 14. AmPlus 50 and 100 Amplifiers and Accessories............................................................. 47

Packing List Power Amplifier Accessory Kit (see Figure 12) .................................................... 48

Figure 12. Accessory Kit Packing Diagram.................................................................................... 48

Part List Remote Volume Control (see Figure 13)....................................................................... 49

Figure 13. Remote Volume Control exploded view........................................................................ 49

Packing List AmPlus 50 and 100 Amplifier (see Figure 14) ....................................................... 50

Figure 14. AmPlus Series Amplifier Packing Diagram ................................................................... 50

Part List AmPlus 100 Amplifier Accessory Transformer (see Figure 15).................................. 51

Figure 15. AmPlus 100 Accessory Transformer exploded and packing view ................................. 51

Part List AmPlus 50 and 100 Amplifier Rack Mount Accessory Kit (see Figure 16) ................ 52

Figure 16. AmPlus 50 and 100 Amplifier Rack Mount Accessory Kit ............................................. 52

Device Pin-out Diagrams.......................................................................................................... 53-57

Troubleshooting Tips..................................................................................................................... 58

CAUTION: THE AMPLUS 100 AND AMPLUS 50 AMPLIFIERS CONTAIN

NO USER SERVICEABLE PARTS. TO PREVENT WARRANTY INFRACTIONS, REFER SERVICING TO WARRANTY SERVICE STATIONS OR FACTORY SERVICE.

PROPRIETARY INFORMATION

THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OF

BOSE

CORPORATION WHICH IS BEING FURNISHED ONLY

FOR THE PURPOSE OF SERVICING THE IDENTIFIED BOSE

PRODUCT BY AN AUTHORIZED BOSE SERVICE CENTER OR

OWNER OF THE BOSE PRODUCT, AND SHALL NOT BE

REPRODUCED OR USED FOR ANY OTHER PURPOSE.

SAFETY INFORMATION

1. Parts that have special safety characteristics are identified by the symbol on schematics or by special notes on the parts list. Use only replacement parts that have

critical characteristics recommended by the manufacturer.

2. Make leakage current or resistance measurements to determine that exposed parts are acceptably insulated from the supply circuit before returning the unit to the customer. Use the following checks to perform these measurements:

A. Leakage Current Hot Check

(1) With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. Do not use an isolation transformer during this test. Use a leakage current tester or a metering system that complies with American National Standards Institute (ANSI) C101. "Leakage Current for Appliances" and Underwriters Laboratories (UL) 1492 (71).

(2) With the unit AC switch first in the ON position and then in the OFF position,

measure from a known earth ground (metal water pipe, conduit, etc.) to all exposed metal parts of the unit (antennas, handle bracket, metal cabinet, screwheads, metallic overlays, control shafts, etc.), especially any exposed

metal parts that offer an electrical return path to the chassis.

(3) Any current measured must not exceed 0.5 milliamp.

(4) Reverse the unit power cord plug in the outlet and repeat test.

ANY MEASUREMENTS NOT WITHIN THE LIMITS SPECIFIED HEREIN

INDICATE A POTENTIAL SHOCK HAZARD THAT MUST BE ELIMINATED

BEFORE RETURNING THE UNIT TO THE CUSTOMER.

B. Insulation Resistance Test Cold Check

(1) Unplug the power supply and connect a jumper wire between the two prongs of the plug.

(2) Turn on the power switch of the unit.

(3) Measure the resistance with an ohmmeter between the jumpered AC plug

and each exposed metallic cabinet part on the unit. When the exposed metallic part has a return path to the chassis, the reading should be

between 1 and 5.2 Megohms. When there is no return path to the chassis, the reading must be "infinite". If it is not within the limits specified, there is the possibility of a shock hazard, and the unit must be repaired and rechecked before it is returned to the customer.

ELECTROSTATIC DISCHARGE SENSITIVE

(ESDS) DEVICE HANDLING

This unit contains ESDS devices. We recommend the following procedures when repairing, replacing, or transporting ESDS devices.

• Perform work at an electrically grounded work station.

• Wear wrist straps that connect to the station, or heel straps that connect to conductive floor

mats.

• Avoid touching the leads or contacts of ESDS devices or PC boards even if properly

grounded. Handle boards by the edges only.

• Transport or store ESDS devices in ESD protective bags, bins, or totes. Do not insert

unprotected devices into materials such as plastic, polystyrene foam, clear plastic bags, bubble wrap, or plastic trays.

WARRANTY INFORMATION

The following products are covered by a 5-year transferable limited warranty.

• Bose

• Equalizer Card

• Optional Opti-Voice

• Optional Source Input expansion card

AmPlus™ 100 and AmPlus 50

Page card

Table 1. Amplifier Comparison Chart

Features AmPlus 100 AmPlus 50

Inputs (balanced) 2 2 Line Outputs (balanced) 2 None Outputs

-Channel 1

-Channel 2

-70V Option Cards

-Opti-Voice® Page Card

-Opti-Source™ Card

-EQ Cards (various)

65 Watts 65 Watts

100 Watts

Yes Yes

Yes, 2

70 Watts

None

50 Watts

Yes, 1

No No

AMPLUS™ 100 AMPLIFIER SPECIFICATIONS

Power Output

Stereo: 65W per channel into 4Ω

50W per channel into 8Ω

70V bridged mono: 100W into 98Ω

Ω: 50W @ 70V output into 98Ω

70V/4

65W @ Ch2 output into 4Ω

Input Sensitivity

315mV required to drive both channels to full power in any mode.

Input Attenuation

0dB to -

∞

Input Impedance

32kΩ balanced, 11kΩ unbalanced

Line Output Impedance

600Ω

Line Output Distortion

≤0.2%

Frequency Response (active EQ bypassed)

4Ω output: 40Hz - 16kHz, ±1dB 70V output: 60Hz - 16kHz, ±1dB

Special Features

Remote volume control Turn on/off muting Clip detection and limiter Short circuit protection DC offset protection Thermal limiting Stable into reactive loads RFI protection UL and TUV approvals

Terminations

Inputs and outputs are quick-connect terminal blocks

Optional Accessories

EQ Cards (Model 1B, Models 8 and 25/32) Source Card Page Card

Operating Temperature Range (passively cooled)

12˚F to 120˚F (-10˚C to +50˚C)

AC Power Consumption

350 Watts max, 100/120Vac, 50-60Hz 350 Watts max, 220/240Vac, 50-60Hz

THD@ Rated Power

4Ω output: ≤2% THD (40Hz - 16kHz) 70V output: ≤2% THD (60Hz - 16kHz)

Hum and Noise

Line output: 92dB Power amplifier output: 80dB below rated output with 4Ω load

Controls

Inputs 1 and 2, input attenuation, remote volume, bass adjust 1 and 2, Input Mode and Amplifier Mode switches.

LED Indicators

Power: front panel

Size (Desk Mount)

17"W x 10"D x 3 3/4"H (43.2 x 25.4 x 9.52 cm)

(Rack Mount, chassis supported)

19"W x 10"D x 3 3/4"H (48.3 x 25.4 x 9.52 cm)

Weight

25 lb (11.3 kg)

Associated Equipment

Rack mount kit Second zone transformer

AMPLUS™ 50 AMPLIFIER SPECIFICATIONS

Power Output

70V Mono: 50W into 98Ω

Ω Mode: 70W outputs into 4Ω

Input Sensitivity

315mV required to drive amplifier to full power in any mode.

Input Attenuation

0dB to -

∞

Input Impedance

32kΩ balanced, 11kΩ unbalanced

Input/Output Configurations

1. Mono into 4Ω load

2. Mono into 70V load

3. As an extension to the AmPlus 100 amplifier

Frequency Response (active EQ bypassed)

4Ω output: 40Hz - 16kHz, ±1 dB 70V output: 60Hz - 16kHz, ±1 dB

THD@ Rated Power

4Ω output: ≤2% THD (40Hz - 16kHz) 70V output: ≤2% THD (60Hz - 16kHz)

Hum and Noise

Power amplifier output: 80dB below rated output with 4Ω load

Controls

Inputs 1 and 2, input attenuation, remote volume, bass adjust affects bandwidth of 50Hz - 150Hz by 0 - 10dB, Amplifier Mode switches.

Special Features

Remote volume control Turn on/off muting Clip detection and limiter Short circuit protection DC offset protection Thermal limiting Stable into reactive loads RFI protection UL and TUV approvals

Terminations

Inputs and outputs are quick-connect terminal blocks

Optional Accessories

EQ cards (Model 1B, Models 8 and 25/32)

Operating Temperature Range (passively cooled)

12˚F to 120˚F (-10˚C to +50˚C)

AC Power Consumption

200 Watts max, 100/120Vac, 50-60Hz 200 Watts max, 220/240Vac, 50-60Hz

Size (Desk Mount)

17"W x 10"D x 3 3/4"H (43.2 x 25.4 x 9.52 cm)

(Rack Mount, chassis supported)

19"W x 10"D x 3 3/4"H (48.3 x 25.4 x 9.52 cm)

Weight

20 lb (9.1 kg)

LED Indicators

Power: front panel

Associated Equipment

Rack mount kit

AMPLUS™ 100 THEORY OF OPERATION

Introduction:

The AmPlus 100 Business Music Amplifier is a two channel amplifier intended for business music and other installed sound systems. Its two inputs pass through the Opti-Voice Opti-Source™ Option Cards and Equalizer cards, if they are installed. These cards expand the number of inputs and outputs of the basic AmPlus 100, adding special features of paging, source selection, and priority override.

Sheet 1 of 3

Refer to the AmPlus 100 schematic diagram, sheet 1 of 3 for the following information. Note: The designators inside the brackets “[ ]” are the schematic grid coordinates which

are provided in order to make it easier to locate components on the schematic sheet indicated in the description.

The Channel 1 and Channel 2 Inputs at J1 [D8] are the "A" inputs on the AmPlus 100 and accept line level sources. U100A [D7] and U101B [C7] are unity gain, differential input amplifiers, with inputs well protected against RF and ESD. Ch 2 coming from U101B can pass through S1 [D7], the Mono/Dual Mono/2-Ch switch, in the 2-Ch position. In other positions of S1, Ch 2 is ignored unless S7 [C7], the 2-Ch/Mixer switch, is in the Mixer position, in which case Ch 2 and Ch 1 are mixed in the proportion set by R1 and R2, the Ch 1 and Ch 2 gain trim switches. After buffers U106A/B, the Ch 1 and Ch 2 signals are presented to one of the two inputs of U102 [D6] and U103 [C6], op amps with a pair of input stages and a selector mechanism, acting as a selector switch. If no option card is in the #1 position at J2 [C7], U102/103 pass the Ch 1 and Ch 2 A input signals straight through; if either a source or a page option card is in the #1 slot at J2, its output will be selected to pass forward into the AmPlus 100 signal path.

If an option card is installed in the #1 slot at J2, then the Ch 1 and Ch 2 A input signals are sent to the option card, and will be processed on that option card and returned to the AmPlus 100 along with the other signals contributed by the option card. The switching action of U102/103 is controlled by the DC level on pin 1. Normally, with no option card in the #1 slot at J2, this pin is pulled high, but when an option card is in place it shorts J2-5, pulling U102/103 pin 1 toward ground.

Page and

Continuing forward on Sheet 1, [coordinates 5D and 5C], the Ch 1 and Ch 2 signals encounter another pair of switched op amps, U104/105 and the option card #2 connector at J3 [C6]. Signal flow here is handled in the same manner as around option card #1: if no option card is installed in slot #2 at J3, the signals pass through; otherwise, they enter the option card and are processed along with that card's sources before being returned to the main AmPlus 100 signal path.

Equalizer cards can be placed in J9 [D5] (for Ch 1) and in J10 [C5] (for Ch 2). If there is no EQ card in J9, the output from U104 passes through the unity gain buffer U100B, but if there is an EQ card, it "overrides" the signal from U104, substituting equalized audio from the EQ card. A similar arrangement for Ch 2 uses U101C. Special switching in the Ch 2 path after U101C allows the use of a single EQ card in the J9 slot in the cases where the source is being handled in mono or dual mono (in dual mono, R3, the Zone 2 Trim, is engaged). When the switch S1 is in the Mono or Dual Mono position, the Ch 1 signal is taken through an inverting stage (U101A) and passed to the Ch 2 path. Inverting the signal phase for the CH2 output compensates for the fact that the connector for the Ch 1 output results in the Ch 1 speaker signal also being inverted. U105 provides this phase inversion for Ch 2 signals when S1 is in the two channel mode.

AMPLUS™ 100 THEORY OF OPERATION

Sheet 1 of 3 (continued)

Note that the U104/105 output is also taken directly, before the EQ card, to two of the volume control VCAs (U204A, D), for use as Line Outputs. U204B, C implement the volume control for the main CH1 and CH2 paths that will move forward in the AmPlus 100 itself.

U204 [C2] is a quad, current in /current out, voltage controlled amplifier. Sections U204A, D, pins 4 and 13, (line output) are controlled only by the remote volume control action, whereas sections U204B, C, pins 5 and 12, (main path) are also controlled, in an OR'd fashion, by the signals CLIP / SC1 [D1] and CLIP / SC2 [A1]. The CLIP / SC signals become active when the power amplifier is clipping and/or attempting to drive a short circuit. This reduces the volume control setting, preventing distortion when a user plays the system too loud, as well as reducing power dissipation when there is a short circuited load.

Connector J4 [A8] ties one or two 10K rheostat-connected remote volume control potentiometers into Q201/221, whose outputs are steered by S5 [B4] (1 Remote / 2 Remotes) into U200 A, B, C, D, [B, C3] which inverts and scales the voltages to the appropriate range needed to control the VCAs. U203A, B [B4] buffer the CLIP / SC signals and OR them into the appropriate sections of U204 via diodes D200, 203. J12 [A8] is reserved for a possible future level control option.

U201A, U202B [B / C1] are the line output buffers, whose outputs are passed through series R/shunt C elements for RFI management. At the junction of the resistors, FETs Q401, 403 [A, B6] provide a power-up/power-down mute so that equipment connected to the line outputs will not experience thumps or pops.

Sheet 2 of 3

Refer to the AmPlus 100 schematic diagram, sheet 2 of 3 for the following information. Sheet 2 concludes the processing of the Ch 1 and Ch 2 signals, preparing them for the

power amplifiers. Circuits on this sheet deal largely with dynamic EQ and switchable EQ, all directed toward the bass region. The CH1 signal (DYNEQ1) entering Sheet 2 [C8] is sent in parallel to five points. Two paths pass through S4 [D6], which selects HP Out (150Hz high pass filter off) or HP In (150Hz high pass filter in). Another path, through R4 [D8], Ch 1 Bass Boost Adjust (50-150Hz) and a bandpass filter, U300B [D5], determines how much bass boost will be present. The signals out of S4 and the bandpass filter are summed in U300A [C4], along with yet another equalized signal.

To develop Dynamic EQ (an equalization where the amount of bass boost applied varies inversely with the signal level), the DYNEQ1 signal [C8] is fed to circuits composed of U300D, Q300, Q301, Q302, U303, U300C, U302A, and U304. U300C, Q300, Q301, Q302 develop a current proportional to the rectified signal level. This current enters the control pin of U302A, a transconductance amplifier, whose output current is multiplied by its control current. U302A is in the negative feedback loop of U300D, which now passes the signal DYNEQ1 with a gain controlled inversely by its own level. At small signals, the gain is the highest. Next, the output of U300D passes through one of two bandpass filters, shaping the signal into a bass boost signal. U304 [C4] selects between two bandpass filters, one centered at 55Hz and appropriate for the Free Space Model 1B Acoustimass® Module, the other at 90Hz, appropriate for full range systems, such as the Model 8, Model 25 and Model 32 Loudspeakers.

Switching to the 55Hz bandpass filter is automatically handled by sensing when a Model 1B EQ card has been inserted in the Ch 1 EQ card socket [J9 on sheet 1 at coordinates D5] (signal EQGND [D1, sheet 1, and B8, sheet 2] is shorted to ground by the Model 1B EQ card when it is plugged in).

AMPLUS™ 100 THEORY OF OPERATION

Sheet 2 of 3 (continued)

Finally, the bass boost signal from the dynamic EQ path rejoins the other signals, (the full range signal, high pass filtered if S4 is in the HP IN position, via S4 and R381, and the manually adjusted bass boost signal via R4 and U300B) in the summing stage U300A [C4]. Now, at last, the Ch 1 and Ch 2 signals are ready to enter the power amplifiers, via connectors J7B [D1] and J8B [B1]. Note that Ch 2 is handled identically by the companion circuits shown below Ch 1's circuits.

Connectors J7B / J8B send the power amplifier power rails (±20V and ±40V) as well as ±12V power and various grounds. The CLIP / SC signals are returned from the power amplifiers via these connectors as well.

DC Offset detection circuits

Circuits that watch for excessive DC offsets of the power amplifier outputs are seen at coordinates C1. Ultimately, these circuits control the operation of relay K600 [sheet 3, B4] whose contacts enable the ±40V supply relays when K600 is energized. The op amp circuits U700 and U701 [sheet 2, C2] watch the Ch 1 and Ch 2 power amplifier outputs for DC offsets greater than about 2.4V. However, in order to keep the relay energized, other conditions must also be met. The ±40V rails and the ±12V rails must each be within a certain degree of symmetry. The Ch 1 power amplifier output is low pass filtered to pass only the DC offset component and is full wave rectified in U700B [C1] and U701A [C2]. A derived center tap from the ±40V supplies is also brought into the full wave rectifier B600 [sheet 3, B4]. The rectifier output is then compared to -2.4V in U701A [sheet 2, C2] (an op amp used as a comparator). If the absolute value of the offset is less than 2.4V, U701A's output is high, which holds Q700 off. Q700 off ensures that Q600 / 601 [sheet 3, B2] can be on, which allows current to flow through the K600 relay coil, energizing it, and thus allowing ±40V to be applied to the power amplifiers.

At coordinates [A, B 1, 2] on Sheet 2 of 3, the power amplifier output wiring is detailed. The power amplifier outputs are always tied to the Ch 1, 2 ± output connector pins, whether the amplifier mode switch S6 [A2] is in the Bridged or the 2 Channel position. However, if S6 is in the Bridged position and if a jumper has been placed between the two XFR CT pins, then the Ch 1 signal and the Ch 2 signals drive the output transformer primary in concert, potentially delivering in excess of 100 watts to the 70 / 100V output pins. Jumpers J409, 410 [sheet 2, A1] select between 70V and 100V operation.

Sheet 3 of 3

Refer to the AmPlus 100 schematic diagram, sheet 3 of 3 for the following information. Sheet 3 outlines the power amplifier and power supply circuits. Channel 1 circuitry is

explained below, Channel 2 operation is identical. The Ch 1 amplifier is built around a power amplifier IC, U500 [C6], augmented by class G transistors. For U500 audio output levels between about ±20V, U500 acts on its own, with its power coming from the ±20V rails via D502 / 509 [C, D5]. When the input signal rises, demanding an output in excess of about ±20V, transistors Q500, 501, 502 (positive rail) and Q503, 504, 505 (negative rail) come into play. Each of these transistor trios is driven by the input signal, via steering diodes D501, 507, and turn on as the higher signal peaks dictate. When Q502 is on, it handles part of the power dissipation by passing the loudspeaker current through power devices in series with the U500 rails. This allows U500 to deliver higher voltage, higher current power to its load while still staying within acceptable IC power dissipation limits. For those portions of the audio output waveform greater than about ±20V, the class G power transistors Q502, Q505 dissipate part of the power.

AMPLUS™ 100 THEORY OF OPERATION

Sheet 3 of 3 (continued)

The power amplifier is equipped with a clip detector circuit, implemented with U503 [D7], an LM311 comparator, and associated parts. The comparator watches the differential input voltage at the power amplifier input pins and compares it to 120mV. If the power amplifier, a feedback amplifier, is for any reason unable to deliver the output voltage requested by the source, linear operation ceases and an error voltage develops across its input pins. Inability to deliver the requested output voltage can occur if there is a short circuit on the amplifier output, a DC offset from some kinds of failures, or from overdriving the amplifier. Whatever the cause, if the input error voltage exceeds the threshold, the LM311 output will go low, toward the -12V supply. Active (low-going) CLIP / SC signals are fed through J7 pin 12 back to the VCA volume control IC, U204 on Sheet 1 [C2], where they turn the gain down to eliminate the stress of the overload situation. If the power amplifier starts to clip, the feedback signal acts as a limiter to keep the amplifier out of the distorted clipping region.

The AmPlus 100 power supply can be configured for either 120V (60Hz) or 230V (50 or 60Hz) AC mains by the appropriate placement of jumpers J603, J605, J606. This is shown on Sheet 3 at coordinates A6, 7, and 8. The AC mains voltage is stepped down and rectified, creating unregulated ±40V and ±20V rail pairs for use by the power amplifier. Regulators U600, 601 [A3] derive ±12V from the ±20V supplies for use by the op amp circuits. The bridge rectifiers B600, and B601 are fused against overload, while the ±12V supply is fused by 1/4 watt resistors R602, and R603. Also on Sheet 3, [B2], are Q600 and Q601, the relay drive transistors controlled by RELAY, from Sheet 2.

AMPLUS™ 50 THEORY OF OPERATION

Introduction:

The AmPlus 50 Business Music Amplifier is a single channel amplifier in most ways identical to the AmPlus 100. Both amplifiers are built in similar chassis using the same PCBs, but most of the Ch 2 parts are omitted in AmpPlus 50.

Note: Refer to the appropriate AmPlus 50 Schematic diagram sheet as indicated below for the following information.

Note: The designators inside the brackets “[ ]” are the schematic grid coordinates which are provided to make it easier to locate components on the schematic sheet indicated in the description.

Note: The components not used in the AmPlus 50 Amplifier are indicated on the schematic diagram as optional (opt).

Sheet 1 of 3

The discussion for the AmPlus 100 applies to the AmPlus 50, with a few exceptions. The Ch 1 and Ch 2 at J1[D8] inputs are summed after their input buffers U100 and U101 [C/D7] and are passed through the Ch 1 path. There are no connectors or slots for the #1 [J2] or #2 [J3] option cards, nor for the Ch 2 EQ card [J10]. There are no line outputs, and only one remote volume control input [J4]. Only the DYNEQ 1 output signal from Sheet 1 passes to Sheet 2. Only the CLIP / SC1 signal is passed into Sheet 1.

Sheet 2 of 3

The discussion for the AmPlus 100 applies to the AmPlus 50, with a few exceptions. Only the Ch 1 path of dynamic and fixed EQ circuits is populated, and only the Ch 1 power amplifier connector is provided. The output connector provides either 4 ohm or 70/100V CV, (Constant Voltage) outputs, as selected by S6 for Ch 1.

Sheet 3 of 3

The AmPlus 50 version is identical except that only the Ch 1 power amplifier module is installed.

(R5)

Gain

Ch. 2

Bass

(R4)

Gain

Ch. 1

Bass

(S4)

Filter

Switch

Pass

High-

Channel 2

Input

section1 of 2

Switch (S1)

Input Mode

Mono

Channel 1

Input

Bass Boost

+ -

70V

Figure 1. AmPlus™ 100 Amplifier Block Diagram

+ -

CH. 1

Amplifier

Outputs

CH. 2

Power

+ -

XFMR

Dynamic

2 Ch.

Bass Boost

Power Amp 2

70V Bridged

Switch

(S6)

Mode

Amp.

Dynamic

Power Amp 1

2 Ch.

High Pass

Filter

70V Bridged

Level (R2)

Ch. 2

2 Ch.

(S7)

2-Ch.

Option Card 1

Channel 2

Option Card 2

Channel 2

EQ Card 2

Mono

Dual

Switch

Mix

Mixer

Trim (R3)

Zone 2

Option Card 1

Channel 1

Option Card 2

Channel 1

EQ Card 1

Level (R1)

Ch. 1

Remote

Zone 2

Control 2

VCA

2 Remotes

Remote

Zone 1

Assign Switch (S5)

Control 1

Remote Zone

VCA

1 Remote

VCA 2

2 Ch.

Switch (S1)

Section 2 of 2

Ch. 2

Mono

Dual

Mono

Input Mode

Ch. 1

VCA 1

Line Outputs

(R4)

Ch.1

Gain

Bass

(S4)

Filter

Switch

Pass

High

Channel 2

Input

Channel 1

Input

Power

Amplifier

Outputs

Figure 2. AmPlus™ 50 Amplifier Block Diagram

+ -

70V

+ -

Ch. 1

70V

Bass Boost

4 Ohm

(S6)

Switch

Mode

Dynamic

Amp

High Pass

Filter

Power Amp 1

70V

4 Ohm

Level (R2)

Ch. 2

Level (R1)

Ch. 1

EQ Card

Remote

Zone 1

Control 1

VCA

VCA

AMPLUS™ 100 AMPLIFIER CONTROLS

INPUTS A

Ch1 Ch2

+- +-

2Ch

INPUT

MODE

dual mono mono

LEVEL

Zone 2Ch2Ch1

-6 -6 -6

-10-10 -10

0 0 0-40 dB -40 dB -40 dB

BASS

LEVEL

Ch2Ch1

+10

OFF

+10

REMOTE VOLUME

ZONE 1 ZONE 2

LINE OUTPUT

ZONE 1 ZONE 2

+-+-

POWER AMPLIFIER

70V ZONE1

4-16

ZONE 2 4-16

Ω

+-+-+-

XFR

Inputs - The amplifier comes with two balanced inputs. They can be left and right channels from a stereo source or two distinct monophonic (mono) sources for 2 - zone applications. Two mono sources can also be mixed for single zone applications.

Input Mode - This switch determines how the Channel 1 and Channel 2 inputs are presented to the power amplifier section of the AmPlus 100. There are 3 possible modes.

1. 2 - Channel/Mixer - the inputs remain separate, not summed. Channel 1 and Channel 2 level potentiometers are active in this mode. Use this mode for:

a. Stereo (2 - channel). b. Two distinct sources in a two zone application (2 - channel), 1 source per zone. c. Two distinct sources in a single bridged mono zone (Mix).

MODE

70/100V 2 Ch BRIDGED

Note: In Mix mode both sources, Channel 1 and Channel 2, are presented to the amplifier simultaneously. When the internal source mix switch is in the MIX position, the Channel 1 attenuation controls the source connected to the Channel 1 input. The Channel 2 attenuation controls the source connected to the Channel 2 input.

2. Dual Mono - The Channel 1 and Channel 2 inputs are summed to mono and presented to the power amplifiers as two mono signals. This mode may also be used when driving a 70V

load from the Channel 1 amplifier outputs and a Bose

Model 1B Acoustimass® Bass Module

from the 4Ω Channel 2 outputs - see zone 2 level adjust.

3. Mono Mode - Both inputs, Channel 1 and Channel 2, are summed to mono. Only the Channel 1 level pot is active.

Level - Channel 1 level adjust - In 2 - channel (stereo) mode, this pot affects the signal level at the channel 1 low impedance (4Ω) outputs. In dual mono mode, it controls the zone 1 level. In mono mode, it controls the level of all inputs.

Channel 2 level adjust - In 2-Channel (stereo) mode, this pot controls the signal level at the channel 2 low impedance (4Ω) outputs. This pot is not active in dual mono or mono modes.

Zone 2 level adjust - This pot is only active when the input mode is dual mono. In this mode, this pot controls the signal level at the channel 2 low impedance outputs. This pot is a slave to the channel 1 pot; that is, the channel 1 pot controls the level of both zones in a 2-zone system. However, the zone 2 pot can be used to fine-tune the bass level when using the AmPlus 100 to drive a 70V load connected to the 70V output and a Model 1B Acoustimass Bass Module connected to the channel 2 output. This pot may also be used to fine-tune the bass level when using the AmPlus 100 to drive a 70V load connected to the 70V output and a Model 1B Acoustimass Module connected to the channel 2 output.

AMPLUS™ 100 AMPLIFIER CONTROLS

INPUTS A

Ch1 Ch2

+- +-

2Ch

INPUT MODE

dual mono mono

LEVEL

Zone 2Ch2Ch1

-6 -6 -6

-10-10 -10

0 0 0-40 dB -40 dB -40 dB

BASS

LEVEL

Ch2Ch1

+10

OFF

+10

REMOTE VOLUME

ZONE 1 ZONE 2

LINE OUTPUT

ZONE 1 ZONE 2

+-+-

POWER AMPLIFIER

70V ZONE1

4-16

ZONE 2 4-16

ΩΩ

+-+-+-

XFR

70/100V 2 Ch BRIDGED

Bass Level - Use the bass level pots to increase the output level between 50 Hz and 150 Hz. This is useful for compensating for poor bass cabinet loading or high levels of low-frequency ambient noise. The channel 1 and channel 2 pots are active in all modes of operation.

Remote Volume - When using the amplifier to power one listening zone, connect the remote control unit to the zone 1 (+) pin and the ground pin and set the internal remote volume switch (see figure below) to 1 REMOTE. When using the AmPlus 100 for 2 - zone applications, connect a second remote to the zone 2 (+) pin and the ground pin and set the internal remote volume switch to 2 REMOTES.

High Pass

Mix

EQ 1

Filter

MODE

EQ 2

1 Remote

2 Remote

Line Outputs - Both line output responses are flat (regardless of whether or not you have installed active equalizer cards). The remote volume control affects the line output levels. Both outputs are active in stereo mode. Only zone 1 is active in dual mono and mono modes.

Power Amplifier Outputs - The 70V output becomes active when the amp mode switch is in the 70V position. In this setup, both AmPlus 100 channels are bridged and provide up to 100 Watts to the 70V speakers.

- When the amp mode switch is in the 2-Channel position and a jumper is placed across the Xfr. ct. pins, 50 Watts is available at the 70V output and 65 Watts is available at the channel 2 output. (see illustration at top of page)

- With the amp mode switch in the 2-Channel position, both channel 1 and channel 2 supply 65 Watts into a minimum load of 4Ω.

Internal High Pass Switch - When this switch is in the HPF ON position, frequencies below 150Hz are attenuated at 18dB/Oct. This low frequency roll-off occurs on Channel 1 only. Use this switch for bandlimiting high frequency speakers connected to channel 1 in a bi-amplified system. For example, the 70V/Model 1B system in Figure 7.

Internal Remote Volume Switch - For one zone applications, this switch should be in the 1 REMOTE position. For two zone applications, this switch should be in the 2 REMOTES position.

AMPLUS™ 50 AMPLIFIER CONTROLS

INPUTS A

Ch1

Ch2

+- +-

LEVEL

-6 -6

-10-10

0 0-40 dB -40 dB

BASS

OFF

GAIN

+10

Ch2Ch1

REMOTE VOLUME

POWER AMPLIFIER

70V

4-16

Ω

+-+-

Inputs - The AmPlus 50 amplifier comes with two balanced inputs. They can be left or right. Two mono sources can also be mixed. Since the AmPlus 50 is a single channel amplifier, a stereo source is internally summed to mono.

Level - Channel 1 level adjust - This potentiometer controls the signal level of the channel 1 input source.

Channel 2 level adjust - This potentiometer controls the signal level of the channel 2 input source.

Bass Gain - Use the bass gain pot to increase the output level between 50 Hz and 150 Hz. This is useful for compensating for poor bass cabinet loading or high levels of low frequency ambient noise.

Remote Volume - Connect the remote volume control unit to the zone 1 (+) pin and the ground pin to control the overall level of the amplifier remotely.

MODE

70/100V 4-16

High Pass

Filter

EQ 1

Power Amplifier Outputs - The 70V output is active when the amplifier Mode Switch is in the 70V position. The 4Ω output is active when the amplifier Mode Switch is in the 4Ω position.

Internal High Pass Filter Switch - When this switch is in the HPF ON position, frequencies below 150 Hz are attenuated at 18dB/Oct. Use this switch for bandlimiting high frequency speakers in a bi-amplified system.

DISASSEMBLY/ASSEMBLY PROCEDURES

1. Top Cover Removal

Note: Refer to Figures 3 and 4, as

applicable, for the following procedures. Note: The numbers in the parentheses

correspond to the callouts in Figures 3 and 4.

1.1 Unplug the power cable from IEC connector on the rear of the amplifier.

1.2 Using a phillips-head screwdriver, remove the five screws (1) that secure the top cover (2) to the amplifier chassis (16).

1.3 Lift the top cover straight off.

2. Top Cover Replacement

2.1 Observing orientation, place the top

cover (2) straight down onto the amplifier chassis (16).

2.2 Using a phillips-head screwdriver, secure the top cover to the amplifier chassis using the five screws (1) that were removed in procedure 1.

3. Main PCB Removal

4. Main PCB Replacement

4.1 Orient the main PCB (8) so that the

connectors are aligned with the rear panel of the amplifier chassis (16), and slide the main PCB into place.

4.2 Secure the main PCB to the amplifier chassis using the six screws (9) removed in procedure 3.4.

4.3 Reconnect all connectors unplugged in procedures 3.2 and 3.3.

4.4 Replace the top cover (2) using procedure 2.

5. Amplifier Module Removal

5.1 Remove the top cover (2) using

procedure 1.

5.2 Unplug the appropriate cable connector, (J7B or J8B), for the amplifier module that you wish to remove.

5.3 Remove the two screws (12) that secure the amplifier module to the amplifier chassis (16) and lift the amplifier module straight out.

3.1 Remove the top cover (2) using procedure 1.

3.2 Unplug all of the cable connectors from the rear panel of the amplifier.

3.3 On the main PCB (8), unplug the connectors at J2, J7B, J3, J8B, J602, J601, J400, J401, and J600.

3.4 Using a phillips-head screwdriver, remove the six screws (9) that secure the main PCB to the amplifier chassis (16).

3.5 Lift the main PCB at the edge nearest the amplifier heatsinks, and slide the PCB forward, until the main PCB connectors clear the amplifier rear panel, then lift the PCB straight up.

6. Amplifier Module Replacement

6.1 Place the amplifier module into the

appropriate spot in the amplifier chassis (16) and secure it using the two screws (12) removed in procedure 5.3.

6.2 Plug the amplifier module cable into the appropriate connector (J7B or J8B) on the main PCB (8).

6.3 Replace the top cover (2) using procedure 2.

DISASSEMBLY/ASSEMBLY PROCEDURES

7. Power Transformer Removal

7.1 Remove the top cover (2) using

procedure 1.

7.2 Unplug the transformer cables at J601 and J602 on the main PCB (8).

7.3 Remove the four nuts (5) that secure the power transformer (7) to the amplifier chassis (16).

7.4 Lift the power transformer straight out of the amplifier chassis.

8. Power Transformer Replacement

8.1 Place the power transformer (7) into the

amplifier chassis (16), aligning it over the chassis studs.

8.2 Secure the power transformer to the amplifier chassis using the four nuts (5) removed in procedure 7.3.

10. Audio Transformer Replacement

10.1 Place the audio transformer (3) into

the amplifier chassis (16) with the wires facing toward the main PCB (8), aligning it over the amplifier chassis studs.

10.2 Secure the audio transformer to the amplifier chassis using the two nuts (5) removed in procedure 9.3.

10.3 Plug the audio transformer cables into the main PCB at J400 and J401.

10.4 Replace the top cover (2) using procedure 2.

8.3 Plug the power transformer cables into J601 and J602 on the main PCB (8).

8.4 Replace the top cover (2) using procedure 2.

9. Audio Transformer Removal

9.1 Remove the top cover (2) using

procedure 1.

9.2 Unplug the audio transformer (3) cables from the main PCB (8) at J400 and J401.

9.3 Remove the two nuts (5) that secure the audio transformer to the amplifier chassis (16).

9.4 Lift the audio transformer straight out of the amplifier chassis.

(5 PLACES)

(4 PLACES)

(7 PLACES)

(4 PLACES)

(6 PLACES)

(2 PLACES)

Figure 3. AmPlus™ 100 Amplifier Exploded View

(5 PLACES)

(7 PLACES)

(2 PLACES)

(6 PLACES)

(3 PLACES)

(2 PLACES)

Figure 4. AmPlus™ 50 Amplifier Exploded View

AMPLUS™ 100 TEST SETUP PARAMETERS

Table 2. AmPlus 100 Initial Switch Settings

Control Name Reference Designator Default Setting

Input Mode S1 switch Left (2-Channel/stereo) Source Trim - Channel 1 R1 potentiometer CW (no attenuation) Source Trim - Channel 2 R2 potentiometer CW (no attenuation) Zone 2 Trim R3 potentiometer CW (no attenuation) Bass Adjust - Channel 1 R4 potentiometer CW (full gain) Bass Adjust - Channel 2 R5 potentiometer CW (full gain) High Pass Filter S4 switch left (HPF off) Remote Volume Setup S5 switch left (1 remote) Source Mix S7 switch left (2 - channel) Amp Mode S6 switch left (70V/100V mode)

Table 3. AmPlus 100 Signal Inputs Table

Balanced Inputs

Function Location Type

Source Input (Channel 1)

Source Input (Channel 2)

Source Input (Channel 1)

Source Input (Channel 2)

(J1) Pins 1, 2, and 3 Connect source LO pin to the (-) terminal and

source HI pin to the (+) terminal. Tie the source shield to the ground terminal.

(J1) Pins 3, 4, and 5 Connect source LO pin to the (-) terminal and

source HI pin to the (+) terminal. Tie the source shield to the ground terminal.

Unbalanced (Single-ended) Inputs

(J1) Pins 1, 2, and 3 Connect source HI pin to the (+) terminal and

source ground to the (-) terminal.

(J1) Pins 3, 4, and 5 Connect source HI pin to the (+) terminal and

source ground to the (-) terminal.

Table 4. AmPlus 100 Signal Outputs Table

Function PCB Location Type

Line Output (Channel 1)

Line Output (Channel 2)

Power Amplifier 70V/100V (CV)

Power Amplifier 4Ω/Channel 1

Power Amplifier 4Ω/Channel 2

Power Amplifier XFR (center tap)

J5 (Pins 1, 2, and 3) Impedance-balanced: tie LO to the (-) pin and

the HI to the (+) pin. Tie the source shield pin to the ground terminal.

J5 (Pins 3, 4, and 5) Impedance-balanced: tie LO to the (-) pin and

the HI to the (+) pin. Tie the source shield pin to the ground terminal.

J6 (Pins 1 and 2) Balanced; connect LO to the (-) pin and HI to

the (+) pin.

J6 (Pins 3 and 4) Unbalanced: connect LO to the (-) pin and HI

to the (+) pin.

J6 (Pins 5 and 6) Unbalanced: connect LO to the (-) pin and HI

to the (+) pin.

J6 (Pins 7 and 8) Jumper; short J6-7 and J6-8

AMPLUS™ 100 TEST PROCEDURES

Test Setup Notes:

1. This amplifier is designed to be used

with balanced inputs at J1. If you have a signal generator capable of supplying a balanced input, refer to the balanced inputs info in Table 3. If you can only drive the amplifier using unbalanced (single-ended) inputs, refer to the the unbalanced inputs info in Table 3. Also refer to the appropriate information (balanced or unbalanced) for output levels in the various tables and text.

2. Before testing, make sure you have the connectors for the inputs and outputs at J1, J4, J5, and J6. The part number for the connector kit that includes J1, J4, and J5 is 188620-001. The part number for the J6 connector is 190694-008 for the AmPlus 100 amplifier.

3. Be sure to set the unit switch positions in accordance with Table 2. AmPlus 100 Initial Switch Settings, before testing.

5. Source Input 1 and 2 (summed internally) to 70/100V Output.

6. For the following tests, refer to Tables 3 and 4 for Signal Input and Signal Output connections.

7. For Gain, Response, and Distortion tests, the unit shall be driven from a 600Ω source, and measured across a 10kΩ, 1/4 W resistor terminated across the (+) and ground terminals at the Line Outputs, and across the Speaker Output with a 98Ω, 100W load across the 70/100V outputs.

8. Unless otherwise noted, the remote volume inputs (J4-1 to J4-2 and J4-3 to J4-2) are to be terminated with a 10kΩ resistor.

9. Input Voltage Reference shall be the actual input voltage present at the input, not the open circuit generator output.

4. All tests are to be performed with option cards and eq cards removed.

5. Definition of Signal Paths: The five signal paths that are used during testing are:

1. Source Input 1 to Line Output 1

2. Source Input 2 to Line Output 2

3. Source Input 1 to Speaker Output 1 (4Ω).

4. Source Input 2 to Speaker Output 2 (4Ω).

Table 5. Source Input to 70/100V Speaker Output Test Table

Test Freq. Input (J1) Output (J6)

Gain 1kHz 1 kHz 31.5 mVrms 7.5Vrms± 0.75V (187915-1) Response 1kHz 1 kHz (Ref) 31.5 mVrms 0dBr ± 0.1dB

Response 60 Hz 60 Hz 31.5 mVrms +9.3dBr ± 1.0dB Response 10 kHz 10 kHz 31.5 mVrms -0.25dBr ± 1.0dB THD 1 kHz 31.5 mVrms 0.2% + 0.8% Noise none none -50dBV + 10.0dBV

1. Gain Test; Source Input to Line Output

1.1 Apply a 100mVrms, 1kHz signal to the

Channel 1 and 2 Source Inputs.

1.2 Reference a dB meter to the input level.

1.3 Measure the output level at the Channel 1 and 2 Line Outputs.

11.0Vrms±0.75V (187915-2)

AMPLUS™ 100 TEST PROCEDURES

1.4 The output level at J5 should be

+3.5dBr ± 1dB (balanced inputs), or +13.5dBr ± 1dB (unbalanced inputs).

2. Gain Test; Source Input to 70V/ 100V Speaker Outputs

Note: Refer to Table 5. Source Input to 70/

100V Speaker Output test table for the following tests.

2.1 Set up the unit as listed in the Test Setup Notes section.

2.2 Apply a 31.5mVrms, 1kHz signal to the Signal Input jacks at J1.

2.3 Measure the RMS Output Level using a DMM. It should be as listed in Table 5.

3. Frequency Response Tests; Source Input to 70/ 100V Speaker Outputs

3.1 Set up the unit as listed in the test setup

notes section.

3.2 Reference a dB meter to the input level and perform the Response 1kHz test as listed in Table 5.

5. Noise Test; Source Input to 70/100V Speaker Outputs

5.1 Set up the unit under test as listed in

the Test Setup Notes section.

5.2 With no input signal applied, measure the noise level in the bandwidth of 20Hz to 16kHz.

5.3 Noise level should be

-50dBV + 10.0dBV.

6. 70/ 100V Speaker Output Full Power Test

6.1 Set up the unit under test as listed in

the Test Setup Notes section.

6.2 Apply a 280mVrms, 1kHz signal to both Channel 1 and 2 Source Inputs.

6.3 Using a DMM, measure the output level at the 70V/ 100V Speaker Outputs.

6.4 Output level should be 70Vrms ± 5.0V for 100/ 120V models.

6.5 Output level should be 100Vrms ± 7.0V for 220/ 240V models.

3.3 Reference a dB meter to the output level. This is the reference level.

3.4 Perform the Response 60Hz and Response 10kHz tests as listed in Table 5.

4. Total Harmonic Distortion (THD) Test; Source Input to 70/ 100V Speaker Output

4.1 Set up the unit under test as listed in

the Test Setup Notes section.

4.2 Apply a 31.5mVrms, 1kHz signal to both Channel 1 and 2 Source Inputs and measure the Total Harmonic Distortion at the 70V/100V Speaker Outputs. It should be 0.2% + 0.8%.

7. Power Amplifier Limiter Test

7.1 Set up the unit under test as listed in

the Test Setup Notes section.

7.2 Apply a 175mVrms (balanced inputs) or 95mVrms (unbalanced inputs),100Hz signal to both Channel 1 and 2 Source Inputs.

7.3 Using a DMM, measure the level at the 70/ 100V Speaker Output jack.

7.4 The level should be 80Vrms ± 5.0V with 1.0% + 2.0% THD for 100/ 120V models.

AMPLUS™ 100 TEST PROCEDURES

7.5 The level should be 115Vrms ± 10.0V

with 1.0% + 2.0% THD for 220/ 240V models.

Note: For the following tests, set up the unit under test as listed in the Test Setup Notes section.

Note: Place 4Ω, 100W load resistors across the 4Ω Speaker Outputs at J6 pins 3 & 4, and 5 & 6.

Note: Move the Amp Mode switch (S6) from the 70/100V Bridged position to the 2-Channel position. This will enable the 4Ω outputs at J6.

8. Gain Test; Source Inputs to 4

Ω Speaker Outputs

8.1 Set up the unit under test as listed in the Test Setup Notes section.

8.2 Apply a 31.5mVrms, 1kHz signal to the Signal Inputs at J1.

8.3 Reference a dB meter to the input level.

8.4 Perform the 1kHz Gain test as listed

in Table 6.

9. Response Test; Source Input to 4

Ω Speaker Outputs

9.1 Apply a 31.5mVrms, 1kHz signal to the Channel 1 and 2 Source Inputs at J1.

9.2 Reference a dB meter to this output level at the 4Ω Speaker Output at J6. This is the reference level.

9.3 Perform the 50Hz, 100Hz, 5kHz, and 10kHz Response tests for both channels as listed in Table 6.

10. Bass Performance Test

10.1 Set up the unit under test as listed in

the Test Setup Notes section.

10.2 Apply a 31.5mVrms, 1kHz signal to the Signal Input jacks at J1.

Table 6. Source Input to 4Ω Speaker Outputs

Test Name Frequency Input (J1) Output (J6)

1kHz Gain 1kHz 1kHz Resp 1kHz

50Hz Resp 50Hz 100Hz Resp 100Hz 5kHz Resp 5kHz 10kHz

10kHz

Response THD

1kHz

31.5mV

+14.5dBV ± 1.0dB (balanced inputs) +35.0dB

0dBr ± 0.1dB (REFERENCE)

± 1.0dB (unbalanced inputs)

-2 .0dBr ± 1.0dB (balanced inputs) +7.0dB

± 1.0dB (unbalanced inputs)

+1.25dBr ± 1.0dB (balanced inputs) +9.5dB

0dBr ± 1.0dB (balanced inputs)

+7.5dB

-0.25dBr ± 1.0dB (balanced inputs)

+10.0dB

± 1.0dB (unbalanced inputs) ± 1.0dB (unbalanced inputs)

± 1.0dB (unbalanced inputs)

31.5mV 0.2% + 0.8%

Table 7. Bass Performance Tests

Test Name Frequency Input (J1) Output (J6)

Bass, 1kHz 1kHz 31.5mV 0dBr ± 0.1dB Bass, 20Hz 20Hz 31.5mV -4.5dBr ± 2dB

Bass, 100Hz 100Hz 31.5mV +11.0dBr ± 2dB

AMPLUS™ 100 TEST PROCEDURES

10.3 Reference a dB meter to the output

level. This is the reference level.

10.4 Perform the 20Hz and 100Hz tests as listed in Table 7.

Note: The following test is for channel 1 only, there is no high pass filter circuit for channel 2.

11. Channel 1 High Pass Filter Test

11.1 Set up the unit under test as listed in

the Test Setup Notes section.

11.2 On the main PCB, place the High Pass Filter switch (S4) to the HPF IN position.

11.3 Apply a 31.5mVrms, 1kHz signal to the Channel 1 Source Input.

11.4 Reference a dB meter to this output level.

11.5 Apply a 31.5mVrms, 50Hz signal to the Channel 1 Source Input.

11.6 Measure the output at Channel 1. It should be -22.0dBr ± 3dB (balanced inputs), or +12.5dBr ± 3dB (unbalanced inputs).

12.5 Measure the output at the Channel 1 4Ω Speaker Outputs. It should be

-45dBV +5.0dBV.

12.6 Measure the output at the Channel 2 4Ω Speaker Outputs. It should be

-45dBV +5.0dBV.

12.7 On the main PCB, place the Remote Zone Assign switch (S5) to the 2 Remotes position.

12.8 Measure the output at the Channel 2 4Ω Speaker Outputs. It should be

-45dBV +5.0dBV.

13. D.C. Offset Test

13.1 Set up the unit under test as listed in

the Test Setup Notes section.

13.2 With both inputs terminated, and with no signal applied, measure the D.C. voltage at the Channel 1 and 2, 4Ω Speaker Outputs.

13.3 It should be 0mVDC ± 10mVDC for both channels.

12. Remote Volume Attenuation Test

12.1 Set up the unit under test as listed in

the Test Setup Notes section.

12.2 Place a jumper from J4-1 to J4-2 and from J4-2 to J4-3. This will apply full attenuation to the VCA's for both channel 1 and 2.

12.3 On the main PCB, place the Remote Zone Assign switch (S5) in the 1 Remote position.

12.4 Apply a 280mVrms, 1kHz signal to the channel 1 and 2 Source Inputs.

AMPLUS™ 50 TEST SETUP PARAMETERS

Table 8. AmPlus 50 Initial Switch Settings

Control Name Reference Designator Default Setting

Source Trim - Channel 1 R1 potentiometer CW (no attenuation) Source Trim - Channel 2 R2 potentiometer CW (no attenuation) Bass Adjust R4 potentiometer CW (full gain) High Pass Filter S4 switch Left (HPF OFF) Amp Mode S6 switch Left (70V/100V mode)

Table 9. AmPlus 50 Signal Inputs Table

Balanced Inputs

Function Location Type

Source Input (Channel 1)

Source Input (Channel 2)

Source Input (Channel 1)

Source Input (Channel 2)

(J1) Pins 1, 2, and 3 Connect source LO pin to the (-) terminal and

source HI pin to the (+) terminal. Tie the source shield to the ground terminal.

(J1) Pins 3, 4, and 5 Connect source LO pin to the (-) terminal and

source HI pin to the (+) terminal. Tie the source shield to the ground terminal.

Unbalanced (Single-ended) Inputs

(J1) Pins 1, 2, and 3 Connect source HI pin to the (+) terminal and

source ground to the (-) terminal.

(J1) Pins 3, 4, and 5 Connect source HI pin to the (+) terminal and

source ground to the (-) terminal.

Table 10. AmPlus 50 Signal Outputs Table

Function PCB Location Type

Power Amplifier 70V/100V (CV)

Power Amplifier 4Ω/Channel 1

J6 (Pins 1 and 2) Balanced; connect LO to the (-) pin and HI to

the (+) pin.

J6 (Pins 3 and 4) Unbalanced: connect LO to the (-) pin and HI

to the (+) pin.

AMPLUS™ 50 TEST PROCEDURES

Test Setup Notes:

1. This amplifier is designed to be used

with balanced inputs at J1. If you have a signal generator capable of supplying a balanced input, refer to the balanced inputs info in Table 9. If you can only drive the amplifier using unbalanced (single-ended) inputs, refer to the the unbalanced inputs info in Table 9. Also refer to the appropriate information (balanced or unbalanced) for output levels in the various tables and text.

2. Before testing, make sure you have the connectors for the inputs and outputs at J1, J4, and J6. The part number for the connector kit that includes J1, and J4 is 188620-001. The part number for the J6 connector is 190694-004 for the AmPlus 50 amplifier.

3. Be sure to set the unit switch positions in accordance with Table 8. AmPlus 50 Initial Switch Positions, before testing.

4. All tests are to be performed with the eq card removed.

6. For the following tests, refer to Tables 9 and 10 for Signal Input and Signal Output connections.

7. For Gain, Response, and Distortion tests, the unit shall be driven from a 600Ω source. Measurement at the Speaker Outputs shall be performed with a 4Ω, 100W load across the 4Ω outputs, and with a 98Ω/100W load resistor across the 70/100V Speaker Output.

8. Unless otherwise noted, the remote volume input (J4-1 to J4-2) is to be terminated with a 10kΩ resistor.

9. Input Voltage Reference shall be the actual input voltage present at the input, not the open circuit generator output.

1. Gain Test; Source Input to 70V/100V Speaker Output

Note: Refer to Table 11. Source Input to

70/ 100V Speaker Output test table for the following tests.

5. Definition of Signal Paths: The three signal paths that are used during

1.1 Set up the unit as listed in the Test Setup Notes section.

testing are:

1. Source Input 1 to Speaker Output 1 (4Ω).

1.2 Perform the Speaker CV Gain Test as listed in Table 11.

2. Source Input 2 (summed with channel 1) to Speaker Output 1 (4Ω).

3. Source Input 1 and 2 (summed

1.3 Measure the Output Level using a DMM at J6.

internally) to 70/ 100V Output.

Table 11. Source Input to 70/100V Speaker Output test table

Test Freq. Input (J1) Output (J6)

Spkr CV Gain 1kHz 100mVrms 22.0V± 5.0Vrms (100/120V only)

32.0V±5.0Vrms (220/240V only)

Response 1kHz 1kHz 100mVrms 0dBr±0.5dB (REFERENCE) Response 60Hz 60Hz 100mVrms +9.3dBr ± 1.0dB (balanced inputs)

+7.5dB±1.0dB (unbalanced inputs)

Response 10kHz 10kHz 100mVrms -0.25dBr ± 1.0dB (balanced inputs)

+9.0±1.0dB (unbalanced inputs) THD 1kHz 100mVrms 0.2% + 0.8% Noise none none -50dBV+ 10.0dBV

AMPLUS™ 50 TEST PROCEDURES

2. Frequency Response Tests; Source Input to 70/100V Speaker Output

2.1 Set up the unit as listed in the Test

Setup Notes section.

2.2 Reference a dB meter to the input level and perform the 1kHz Response Test as listed in Table 11.

2.3 Reference a dB meter to the output level. This is the reference level.

2.4 Perform the 60Hz and 10kHz Response tests as listed in Table 11.

3. Total Harmonic Distortion (THD) Test; Source Input to 70/100V Speaker Output

3.1 Set up the unit under test as listed in

the Test Setup Notes section.

3.2 Apply a 100mVrms, 1kHz signal to both Channel 1 and 2 Source Inputs and measure the Total Harmonic Distortion at the 70V/100V Speaker Output. It should be 0.2% + 0.8%.

4. Noise Test; Source Input to 70/100V Speaker Outputs

4.1 Set up the unit under test as listed in

the Test Setup Notes section.

4.2 With no input signal applied, measure the noise level in the bandwidth of 20Hz to 16kHz.

5. 70/ 100V Speaker Output Full Power Test

5.1 Set up the unit under test as listed in

the Test Setup Notes section.

5.2 Apply a 280mVrms, 1kHz signal to both Channel 1 and 2 Source Inputs.

5.3 Using a DMM, measure the output level at the 70V/ 100V Speaker Output.

5.4 Output level should be 70Vrms ± 5.0V for 100/ 120V models.

5.5 Output level should be 100Vrms ± 7.0V for 220/ 240V models.

6. Power Amplifier Limiter Test

6.1 Set up the unit under test as listed in

the Test Setup Notes section.

6.2 Apply a 175mVrms (balanced inputs), or 95mVrms (unbalanced inputs), 95Hz signal to both Channel 1 and 2 Source Inputs.

6.3 Using a DMM, measure the level at the 70/ 100V Speaker Output jack.

6.4 The output level should be 70Vrms ± 5.0V with 1.0% + 2.0% THD for 100/ 120V models.

6.5 The output level should be 100Vrms ± 7.0V with 1.0% + 2.0% THD for 220/ 240V models.

4.3 Noise level should be

-50dBV + 10.0dBV.

AMPLUS™ 50 TEST PROCEDURES

Note: For the following tests, set up the

unit under test as listed in the Test Setup Notes section.

Note: Move the Amp Mode switch (S6) from the Constant Voltage (CV) position to the 4Ω position. This will enable the 4Ω output at J6.

Note: Place a 4Ω, 100W load resistor across the 4Ω Speaker Output at J6 pins 3 & 4.

Note: Refer to Table 12. Source Inputs to 4Ω Speaker Outputs for the following tests.

7. Gain Test; Source Inputs to 4

7.1 Apply a 100mV, 1kHz signal to the

Signal Inputs at J1.

Ω Speaker Outputs

7.3 Measure the output level at the Signal Outputs at J6. It should be +14.5dBV

± 1.0dB (balanced inputs) or +35.0dB ± 1.0dB (unbalanced inputs).

8. Response Test; Source Input to 4

8.1 Set up the unit under test as listed in

the Test Setup Notes section.

8.3 Apply a 100mVrms, 1kHz signal to the Channel 1 and 2 Source Inputs at J1.

8.4 Reference a dB meter to this output level at the 4Ω Speaker Output at J6. This is the reference level.

8.5 Perform the 50Hz, 100Hz, 5kHz, and 10kHz tests as listed in Table 12. Source Inputs to 4Ω Speaker Outputs.

Ω Speaker Outputs

7.2 Reference a dB meter to this input level.

Table 12. Source Inputs to 4Ω Speaker Output

Test Name Frequency Input (J1) Output (J6)

Gain 1kHz 100mV +14.5dBV ± 1.0dB (balanced inputs)

+35.0dBV ± 1.0dB (unbalanced inputs) Resp 1k 1kHz 100mV 0dBr ± 0.1dB (REFERENCE) Resp 50 50Hz 100mV -2.0dBr ± 1.0dB (balanced inputs)

+7.0dBr ± 1.0dB (unbalanced inputs) Resp 100 100Hz 100mV +1.25dBr ± 1.0dB (balanced inputs)

+9.5dBr ± 1.0dB (unbalanced inputs) Resp 5k 5kHz 100mV 0dBr ± 1.0dB (balanced inputs)

+7.5dBr ± 1.0dB (unbalanced inputs) Resp 10k 10kHz 100mV -0.25dBr ± 1.0dB (balanced inputs)

+10.0dBr ± 1.0dB (unbalanced inputs) THD 1kHz 100mV 0.2% + 0.8% Noise none none -50dBV + 10.0dBV

Table 13. Bass Performance Tests

Test Name Frequency Input (J1) Output (J6)

Bass, 1kHz 1kHz 31.5mV 0dBr ± 0.1dB Bass, 20Hz 20Hz 31.5mV -4.5dBr ± 2dB

Bass, 100Hz 100Hz 31.5mV +11.0dBr ± 2dB

AMPLUS™ 50 TEST PROCEDURES

9. Bass Performance Tests

Note: Refer to table 13 for the following

tests.

9.1 Set up the unit under test as listed in the Test Setup Notes section.

9.2 Apply a 31.5mVrms, 1kHz signal to the Signal Input jacks at J1.

9.3 Reference a dB meter to the output level. This is the reference level.

9.4 Perform the Bass 20Hz, and 100Hz tests as listed in Table 13.

10. High Pass Filter Test

Note: This test checks the response of the

150Hz high pass filter.

11. D.C. Offset Test

11.1 Set up the unit under test as listed in

the Test Setup Notes section.

11.2 With both inputs terminated, and with no signal applied, measure the D.C. voltage at the Channel 1, 4Ω Speaker Output.

11.3 It should be 0mVDC ± 10mVDC.

10.1 Set up the unit under test as listed in

the Test Setup Notes section.

10.2 On the main PCB, place the High Pass Filter switch (S4) to the HPF IN position.

10.3 Apply a 31.5mVrms, 1kHz signal to the Channel 1 Source Input (J1).

10.4 Reference a dB meter to this output level.

10.5 Apply a 31.5mV, 50Hz signal to the Channel 1 Source Input.

10.6 Measure the output at Channel 1 (J6). It should be -22.0dBr ± 3dB (balanced inputs), or +12.5dBr ± 3dB (unbalanced inputs).

INSTALLATION DIAGRAM NOTES

The installation diagrams on the following pages are provided to give you an idea as to how this product may be installed in the field, so that you can more easily troubleshoot a problem if the unit has been removed from its installation for you to repair.

The diagrams are divided into three sections:

1. The first section is labelled "Example Listening Zone", and in block diagram format, shows how the source is connected to the amplifier, and the amplifier is connected to the loudspeakers as well as the remote volume control(s) for that type of installation.

2. The next section is labelled "Rear Panel Hookup", and shows the hookup on the rear panel of the amplifier, as well as the various switch settings for that type of installation.

3. The bottom section is labelled "AmPlus™ 50 (or 100) Signal Flow", and in block diagram format, depicts the signal flow and switch settings for the particular amplifier used for that type of installation. The grayed out lines in the block diagram indicate signal paths and blocks not used in that particular application.

Using this information, you should be able to more closely approximate the installation of the unit in order to more easily troubleshoot it.

Example Listening Zone

Source

AmPlus™ 100

Rear Panel Hookup

Remote Volume Control

Ch1

INPUTS A

Ch2

INPUT MODE

dual mono

2Ch

mono

-10

-40 dB

LEVEL

Zone 2Ch2Ch1

-6

-10

-40 dB

BASS

LEVEL

-6

OFF

OFF +10

+10

Ch2Ch1

REMOTE VOLUME

ZONE 1 ZONE 2

+- +- +-+-+-

Internal Switch Settings

Source

Remote Volume: 1 Remote, Ch. 1 High Pass Filter: OFF, 2 Ch./Mixer Switch: 2 Ch. 

L R

Note: Both bass pots are active in this mode. Use both of these controls to make bass level adjustments.

Remote Volume Control

LINE OUTPUT

ZONE 1 ZONE 2

+-+-

70/100V ZONE 1

Tap settings less than or equal to 100W

AmPlus 100 Signal Flow

Ch. 1

Channel 1

Input

Channel 2

Input

Mono

Input Mode Switch section 1 of 2

High Pass Filter Switch

Bass Level Ch. 1

Level

Dual

Mono

Ch. 2 Level

High Pass

Filter

Dynamic

Bass Boost

2 Ch.

2 Ch/ Mixer

Switch

Option Card 1

Channel 1

Mix 2 Ch.

Option Card 1

Channel 2

Power Amp 1

Power Amp 2

Option Card 2

Channel 1

Option Card 2

Channel 2

70/100V Bridged

EQ Card 1

EQ Card 2

70/100V Bridged

2 Ch.

Amplifier Mode Switch

Zone 2

Level

Dual Mono

2 Ch.

VCA 1

Mono

VCA 2

Zone 1

Remote

Zone 2

Remote

Input Mode Switch section 2 of 2

POWER AMPLIFIER

ZONE 2

4-16

VCA

Control 1

Remote Switch

VCA

Control 2

XFR

70/100V 2 Ch. BRIDGED

1 Remote

2 Remotes

MODE

Line Outputs

ZONE 1

ZONE 2

Bass Level Ch. 2

Dynamic

Bass Boost

2 Ch.

Power Amplifier

+ -

70/100V

+ - ZONE 1

Outputs

+ -

ZONE 2

XFR

Figure 5. AmPlus 100 Simple Mono Installation

Example Listening Zone

Source 1

Source 2

AmPlus™ 100

Remote Volume Control

AmPlus™ 100

Rear Panel Hookup

BASS LEVEL

-6

OFF

OFF +10

+10

Ch1

INPUTS A

Ch2

2Ch

INPUT MODE

dual mono

LEVEL

Zone 2Ch2Ch1

-6

-10

mono

-40 dB

-10

-40 dB

+- +- +-+-+-

Source 1

Source 2

1. Adjust the source 1 level with the ch. 1 pot.

3. Internal Switch Settings Remote Volume: 1 Remote, Ch. 1 High Pass Filter: OFF, 2 Ch./Mixer Switch: Mixer position  Note: Both bass pots are active in this mode. Use both of these controls to adjust bass level.

2. Adjust the source 2 level with the ch. 2 pot.

Remote Volume Control

Ch2Ch1

REMOTE VOLUME

ZONE 1 ZONE 2

LINE OUTPUT

ZONE 1

Aux Amp 1

+-+-

ZONE 2

70/100V

POWER AMPLIFIER

ZONE 2

ZONE 1

4-16

Tap settings less than or equal to 100W

XFR

MODE

70/100V 2 Ch. BRIDGED

Tap settings less than or equal to 100W

AmPlus 100 Signal Flow

Source 1

Mono

High Pass Filter Switch

Level

Source 2

Level

High Pass

Filter

Dynamic

Bass Boost

Dynamic

Bass Boost

Dual

Mono

2 Ch.

2 Ch/ Mixer

Switch

Mono

Source 1

Input

Mono

Source 2

Input

Input Mode Switch

section 1 of 2

Bass Level Ch. 1

Bass Level Ch. 2

Figure 6. AmPlus 100 Large Mono Installation using Mixer Feature

Option Card 1

Channel 1

Mix 2 Ch.

Option Card 1

Channel 2

Power Amp 1

Power Amp 2

+ - 70/100V

Option Card 2

Channel 1

Option Card 2

Channel 2

+ -

ZONE 1

70/100V Bridged

Power Amplifier Outputs

2 Ch.

Amplifier Mode Switch

2 Ch.

+ -

ZONE 2

EQ Card 1

EQ Card 2

XFR

VCA 1

Dual

Mono

Zone 2

Level

2 Ch.

Input Mode Switch section 2 of 2

VCA 2

Zone 1 Remote

Zone 2 Remote

VCA

Control 1

Remote Switch

VCA

Control 2

Line Outputs

ZONE 1

ZONE 2

1 Remote

2 Remotes

Example Listening Zone

Source

AmPlus™ 100

Model 1B

Module

Remote Volume Control

Rear Panel Hookup

Ch1

INPUTS A

Ch2

INPUT MODE

dual mono

2Ch

mono

LEVEL

Zone 2Ch2Ch1

-6

-10

0-40 dB

-6

0-40 dB

BASS LEVEL

OFF +10 OFF +10

+- +- +-+-+-

2. Then use Zone 2 and Ch. 2 Bass pots to adjust Bass Module level.

Source

1. First, adjust high frequency speaker

L R

level here.

3. Internal Switch Settings Remote Volume: 1 Remote, Ch. 1 High Pass Filter: ON, 2 Ch./Mixer Switch: 2 Ch.

Ch2Ch1

REMOTE VOLUME

ZONE 1 ZONE 2

LINE OUTPUT

ZONE 1 ZONE 2

Remote Volume Control

POWER AMPLIFIER

70/100V ZONE 1

4-16

+-+-

ZONE 2 4-16

Use jumper

Tap settings, less than or equal to 50W

XFR

MODE

70/100V 2-CH BRIDGED

Model 1B

Module

AmPlus 100 Signal Flow

Ch. 1

Channel 1

Input

Channel 2

Input

Switch section

High Pass Filter Switch

Bass Level Ch. 1

Bass Level Ch. 2

Mono

Input Mode

1 of 2

Level

Dual

Mono

Ch. 2 Level

High Pass

Filter

Dynamic

Bass Boost

Dynamic

Bass Boost

2 Ch.

2 Ch/

Mixer

Switch

Option Card 1

Mix 2 Ch.

Option Card 1

Power Amp 1

Power Amp 2

+ - 70/100V

Channel 1

Channel 2

+ -

ZONE 1

Option Card 2

Channel 1

Option Card 2

Channel 2

70/100V Bridged

Power

Amplifier

Outputs

+ -

2 Ch.

Amplifier Mode Switch

2 Ch.

ZONE 2

EQ Card 1

EQ Card 2

XFR

Zone 2

Level

Dual

Mono

2 Ch.

VCA 1

Mono

Input Mode Switch Section 2 of 2

VCA 2

Zone 1

Remote

Zone 2

Remote

VCA

Control 1

Remote Switch

VCA

Control 2

Line Outputs

ZONE 1

ZONE 2

1 Remote

2 Remotes

Figure 7. AmPlus 100 70/ 100 Volt Mode/ Model 1B Acoustimass® Bass Module Installation

Example Listening Zone

Source

AmPlus™ 100

Accessory 70/100V

Transformer

Rear Panel Hookup

Zone 1 Remote Volume Control

Zone 2 Remote Volume Control

INPUTS A

Ch1 Ch2

+- +- +-+-+-

Source

AmPlus 100 Signal Flow

Ch. 1 Level

Channel 1

Input

Channel 2

Input

Mono

Input Mode Switch

section 1 of 2

High Pass Filter Switch

Bass Level Ch. 1

Dual

Mono

Ch. 2 Level

High Pass

Filter

Dynamic

Bass Boost

2 Ch.

2Ch

2 Ch/ Mixer Switch

INPUT MODE

dual mono mono

LEVEL

Zone 2Ch2Ch1

-6

-10

1. First, adjust the Zone 1 listening level.

2. Then use the Zone 2 pot to adjust the Zone 2 listening level.

3. Internal Switch Settings Remote Volume: 2 Remotes, Ch. 1 High Pass Filter: OFF, 2 Ch./Mixer Switch: 2 Ch.

Option Card 1

Channel 1

-6

-10

0 0 0-40 dB

-40 dB

Mix 2 Ch.

Option Card 1

Channel 2

Power Amp 1

Power Amp 2

BASS

LEVEL

Ch2Ch1

OFF

OFF +10

+10

Zone 1 Remote Volume Control

Option Card 2

Channel 1

Option Card 2

Channel 2

70/100V Bridged

2 Ch.

Amplifier Mode Switch

REMOTE VOLUME

ZONE 1 ZONE 2

EQ Card 1

EQ Card 2

LINE OUTPUT

ZONE 1 ZONE 2

+-+-

Zone 2 Remote Volume Control

Zone 2

Level

Dual Mono

2 Ch.

70/100V ZONE 1

4-16

VCA 1

Mono

VCA 2

Zone 1 Remote Volume Control

Zone 2 Remote Volume Control

POWER AMPLIFIER

ZONE 2 4-16

Use jumper

Accy.

70/100V

XFR

Tap settings: less than or equal to 50 Watts

Input Mode Switch section 2 of 2

VCA

Control 1

Remote Switch

VCA

Control 2

XFR

MODE

70/100V 2 Ch. BRIDGED

Line Outputs

ZONE 1

ZONE 2

1 Remote

2 Remotes

Bass Level Ch. 2

Dynamic

Bass Boost

+ -

70V

+ -

ZONE 1

Power Amplifier Outputs

2 Ch.

+ -

ZONE

XFR

70/100V Accessory

Transformer

TO ZONE 2

Figure 8. AmPlus 100 installation with Two 70/ 100V Listening Zones

Example Listening Zone

Source

AmPlus™ 50

Rear Panel Hookup

Remote Volume Control

INPUTS A

Ch1

Ch2

+- +-

Source

L R

AmPlus 50 Signal Flow

Ch. 1

Channel 1

Input

Channel 2

Input

Bass Gain

High Pass Filter Switch

Level

Ch. 2 Level

High Pass

Filter

Dynamic

Bass Boost

LEVEL

-6 -6

-10-10

0 0-40 dB -40 dB

Ch2Ch1

Internal Switch Settings: High Pass Filter: OFF

BASS GAIN

OFF +10

Remote Volume Control

Power Amp 1

REMOTE VOLUME

70/100V

Amplifier Mode Switch

4-16 70/100V

EQ Card

4-16

POWER AMPLIFIER

70/100V 4-16

+-+-

Tap settings: less than or equal to 50W

Remote

VCA

VCA

Control

MODE

70/100V 4-16

Power Amplifier Outputs

+ - 70/100V

+ - 4-16

Figure 9. AmPlus 50 Simple Mono Installation

PART LIST NOTES

Notes: 1. This part is not normally available from Customer Service. Approval from the Field

Service Manager is required before ordering.

2. The individual parts located on the PCB are listed in the part list.

3. This part is critical for safety purposes. Failure to use a substitute replacement with the same safety characteristics as the recommended replacement may create shock, fire, and/or other hazards.

4. Not used on AmPlus™ 50 amplifier.

5. Used on 120V units only.

6. Used on 240V units only.

MAIN PART LIST

AmPlus™ 100 Amplifier (see Figure 10)

Item

Number

1 SCREW, 6-32 X .5, MACH, FLAT, XREC 190623-008 5 2 COVER TOP, AMP 187966 1 3 TRANSFORMER, AUDIO, 70/100V 188600-001 1 4 CLIP, HEATSINK, BRIDGE RECT. 188568 1 5 NUT, 8-32 HEX W/LKWSHR 100413-2 7 6 CLIP, HEATSINK 188599 2 7 TRANSFORMER, POWER 187985 1

8 PCB ASSY, AMPLUS 100,

120V 240V

9 SCR, MACH, 8-32X 1/4, XREC, DRILK 179096-04 6 10 CLIP, HEATSINK 188598 6 11 INSUL. THERMAL COND, TO-220 188642-001 4 12 SCREW, MACH, #10-32, PAN, XREC 177637-44 4 13 INSUL. THERMAL COND., MULTIWATT 188642-002 2 14 HEATSINK, AMPLUS 50/100 187969 2 15 CONN ASSY, IEC RECEPT, AMPLUS 190621-001 1

16 CHASSIS, BASE, AMPLUS 100

120V 240V

17 SWITCH ASSY, DPST, NEON,

120V 240V

18 HARNESS ASSY, OPTION, 8 COND 188570 2

- HARNESS ASSY, 12 CONDUCTOR, MAIN PCB TO AMP MODULE

Description Part Number Qty. Notes

187917-001 187917-002

187963-001 187963-002

190622-001 190622-002

188571-001 2

1 1

1 1 3

1, 2 1, 2

(5 PLACES)

(4 PLACES)

(7 PLACES)

(4 PLACES)

(6 PLACES)

(2 PLACES)

Figure 10. AmPlus™ 100 Amplifier Exploded View

MAIN PART LIST

AmPlus™ 50 Amplifier (see Figure 11)

Item

Number

1 SCREW, 6-32 X .5, MACH, FLAT, XREC 190623-008 5 2 COVER TOP, AMP 187966 1 3 TRANSFORMER, 70/100V, AUDIO 188600-001 1 4 CLIP, HEATSINK, BRIDGE RECT. 188568 1 5 NUT, 8-32 HEX W/LKWSHR 100413-2 7 6 CLIP, HEATSINK 188599 2 7 TRANSFORMER, POWER 187985 1

8 PCB ASSY, AMPLUS 50,

120V 240V

9 SCR, MACH, 8-32X 1/4, XREC, DRILK 179096-04 6 10 CLIP, HEATSINK 188598 3 11 INSUL. THERMAL COND, TO-220 188642-001 2 12 SCREW, MACH, #10-32, PAN, XREC 177637-44 2 13 HEATSINK, AMPLUS 50/100 187969 1 14 INSUL. THERMAL COND., MULTIWATT 188642-002 1 15 CONN ASSY, IEC RECEPT, AMPLUS 190621-001 1

16 BASE, CHASSIS, AMPLUS 50,

120V 240V

17 SWITCH ASSY, DPST, NEON,

120V 240V

- HARNESS ASSY, 12 CONDUCTOR, MAIN PCB TO AMP MODULE

Description Part Number Qty. Notes

187923-001 187923-002

183056-001 183056-002

190622-001 190622-002

188571-001 1

1 1

1 1 3

1, 2 1, 2

(5 PLACES)

(7 PLACES)

(2 PLACES)

(6 PLACES)

(3 PLACES)

(2 PLACES)

Figure 11. AmPlus™ 50 Amplifier Exploded View

ELECTRICAL PART LIST

Resistors

Reference Designator Description Part Number Notes

R1, 2, 3, 4, 5 POT, RTY, 20K, RIGHT

ANGLE, LOG TAPER

R100, 102, 110, 116, 193, 194, 312,

342, 412, 502, 503, 506, 507, 512, 514, 517, 520, 521, 524, 537, 538, 547, 549, 561, 563, 607, 711, 713

R101, 103, 111, 117, 606 9.09KΩ, 0805, 1/10W, 1% 133625-9091 R104, 105, 112, 118, 121, 171, 180,

181, 200, 201, 213, 214, 217, 219, 220, 221, 236, 237, 304, 311, 313,

330, 335, 341, 343, 370, 372, 505, 510, 519, 526, 560, 564, 567, 569, 600, 601, 705, 706, 708, 709

R106, 115, 182, 183, 184, 185, 186, 187, 188, 189, 202, 223, 235, 245, 246, 247, 401, 408

R113, 130, 133, 181, 190, 192, 213, 214, 219, 237, 244, 328, 369, 391, 604

R120, 170, 171, 210, 211, 212, 215, 216, 218, 300, 331, 357

R126, 131, 132, 141, 142, 152, 153,

164, 302, 303, 317, 318, 333, 334, 347, 348, 500, 501, 509, 515, 516, 525, 536, 546, 608, 700, 701

R150, 154 1.54KΩ, 0805, 1/10W, 1% 133625-1541 R151, 155, 325, 352, 367, 379 14.0KΩ, 0805, 1/10W, 1% 133625-1402 4

R160, 161 3.01KΩ, 0805, 1/10W, 1% 133625-3011 4 R162, 163, 204, 205, 230, 231, 241,

242, 243, 244, 364, 365, 376, 377, 380, 387, 545, 565, 710

R171 10.0KΩ, 0805, 1/10W, 1% 133625-1002 R181, 213, 219, 237 JUMPER, CHIP, 0805 133627 R203, 222 2.00KΩ, 0805, 1/10W, 1% 133625-2001 4 R206, 207, 232, 233 499Ω, 0805, 1/10W, 1% 133625-4990 R234, 326, 327, 358, 359, 382 6.19KΩ, 0805, 1/10W, 1% 133625-6191 4 R301, 332 2.43KΩ, 0805, 1/10W, 1% 133625-2431 4 R305, 339, 410, 704 1MEGΩ, 0805, 1/10W, 5% 133626-1055 4 R306, 307, 337, 338, 504, 518, 535,

543, 702, 703, 712, 714, 715, 717 R308, 340 5.62KΩ, 0805, 1/10W, 1% 133625-5621 4 R310, 316, 336, 345, 362, 371, 373 4.99KΩ, 0805, 1/10W, 1% 133625-4991 4 R314, 344 8.25KΩ, 0805, 1/10W, 1% 133625-8251 4 R315, 346 301KΩ, 0805, 1/10W, 1% 133625-3013 4 R319, 350 25.5KΩ, 0805, 1/10W, 1% 133625-2552 4 R320, 349, 356, 363, 374, 385 26.7KΩ, 0805, 1/10W, 1% 133625-2672 4 R321, 354 4.64KΩ, 0805, 1/10W, 1% 133625-4641 4 R322, 355, 511, 523, 539, 550 6.81KΩ, 0805, 1/10W, 1% 133625-6811 4 R323, 351 4.22KΩ, 0805, 1/10W, 1% 133625-4221 4 R324, 353 6.49KΩ, 0805, 1/10W, 1% 133625-6491 4 R328, 360, 369, 391, 407, 604 JUMPER, CHIP, 0805 133627 4,

1.00KΩ, 0805, 1/10W, 1% 133625-1001 4

10.0KΩ, 0805, 1/10W, 1% 133625-1002 4

100Ω, 0805, 1/10W, 1% 133625-1000 4

JUMPER, CHIP, 0805 133627 AmPlus

47.5KΩ, 0805, 1/10W, 1% 33625-4752 4 100KΩ, 0805, 1/10W, 1% 133625-1003 4

30.1KΩ, 0805, 1/10W, 1% 133625-3012 4

20.0KΩ, 0805, 1/10W, 1% 133625-2002 4

187484-001 4

AmPlus

100

ELECTRICAL PART LIST

Resistors (continued)

Reference Designator Description Part Number Notes

R366, 378 40.2KΩ, 0805, 1% 133625-4022 4 R381, 386 4.02KΩ, 0805, 1/10W, 1% 133625-4021 4 R400, 409 301Ω, 0805, 1/10W, 1% 133625-3010 4 R402, 403 402Ω, 0805, 1% 133625-4020 4 R411 3.32KΩ, 0805, 1/10W, 1% 133625-3321 4

R414, 415, 541, 571 10Ω, 2512, 1W, 5% 181895-10R0 4 R508, 522, 540, 548 220Ω, 2512, 1W, 5% 181895-2200 4

R527, 529, 532, 533 2.49KΩ, 0805, 1/10W, 1% 133625-2491 4 R528, 530, 531, 534 49.9KΩ, 0805, 1/10W, 1% 133625-4992 4 R568, 570 5.90KΩ, 0805, 1/10W, 1% 133625-5901 4 R602, 603 .75Ω, 1210, 1/4W, 5% 180956-R75E

Capacitors

Reference Designator Description Part Number Notes

C1, 2 1000pF, Y-Cap, Rifa P/N:

PME290MA4100M

C100, 103, 111, 116 680pF, 0805, COG, 50V, 5% 133622-681 C104, 105, 107, 112, 114, 117,

160, 163, 180, 255, 315, 332 C106, 108, 113, 118, 130, 131,

140, 141, 151, 153, 161, 162, 198, 199, 216, 217, 240, 241, 244, 245, 249, 251, 252, 253, 254, 301, 304, 305, 313, 314, 316, 317, 321, 322, 330, 331, 337, 341, 347, 408, 409, 521, 526, 532, 533, 534, 535, 602, 603, 604, 605, 608, 609, 614, 615, 616, 617, 618, 619, 620, 701, 702, 703, 705, 706

C120, 170, 333, 707 4.7uF, EL, 105, 35V, 20% 137126-4R7 4 C150, 152, 302, 303, 308, 319,

320, 325, 500, 501, 503, 505, 506, 510, 511, 513, 514, 516, 518, 522, 523, 527, 528, 529, 612, 613, 700

C201, 202, 230, 231, 400, 402, 403, 407

C210, 212, 214, 219, 242, 243, 246, 247, 530, 531, 704

C211, 213, 215, 218, 318, 360 1.0uF, EL, 105, 50V, 20% 137126-1R0 4 C197, 248, 250, 504, 508, 509,

512, 515, 517, 519, 525 C307, 324 1800PF, 0805, COG, 50V, 5% 133622-182 4 C309, 329 .068uF, BOX, 85, 63V, 5% 137127-683 4 C310, 312, 327, 328, 339, 342 .15uF, BOX, 85, 50V, 5% 137127-154 4 C311, 326 .1uF, BOX, 85, 50V, 5% 137127-104 4 C334, 335, 340 .22uF, BOX, 85, 50V, 5% 137127-224

47pF, 0805, COG, 50V, 5% 133622-470 4 .10uF, 0805, Y5V, 25V, 80% 133624 4

10UF, EL, 105, 35v, 20% 149948-100V 4

560pF, 0805, COG, 50V, 5% 133622-561 4 100pF, 0805, COG, 50V, 5% 133622-101 4

1000pF, 0805, COG, 50V, 5% 133622-102 4

170183

ELECTRICAL PART LIST

Capacitors (continued)

Reference Designator Description Part Number Notes

C336, 344, 345, 346 .033uF, BOX, 85, 63V, 5% 137127-333 4 C338, 343 .12uF, BOX, 85, 50V, 5% 137127-124 4 C401, 405, 502, 507, 520, 524 .01uF, 0805, X7R, 50V, 5% 133623-1035 4

C406 .033uF, 0805, X7R, 50V, 10% 133623-333 C606, 607 4700UF, EL, BP, 105, 50V,

20%

C610, 611 4700UF, EL, 105, 50V, 20% 144000-472E

Diodes

Reference Designator Description Part Number Note

B600, B601 RECT, BRIDGE, 100V, 6A 170214 3

187394

D200, 201, 202, 203, 300, 306, 511, 515, 603, 700, 701, 702

D301, 305 SOT-23, BAV70 147249 4 D302, 304, 506, 514, 703 BAV99, SOT23 147239 4 D401, 402, 500, 504, 508, 512 ZENER, 5%, 9.1V, SOT-23 148333 4 D501, 503, 507, 510 1N4531, 5MM 136603 4 D502, 505, 509, 513, 600, 601 RECT, 1.5A, S2A 187479-001 4

Reference Designator Description Part Number Note

Q201, 221, 300, 304, 400, 402, 600, 601, 701

Q301, 302, 305, 306, 700 PNP, SOT, MMBT3906 148596 4 Q401, 403 JFET, TO-92 188634-001 4 Q500, 504, 506, 510 BPLR, N, 60V, 200MA, TO-92 117921 4 Q501, 503, 507, 509 BPLR, P, 60V, 200MA, TO-92 119168 4 Q502, 508 DARL, P, TIP146T 172285 4 Q505, 511 DARL, N, TIP141T 172284 4

SOT, MMBD914LT1 148582 4

Transistors

NPN, SOT, MMBT3904 146819 4

ELECTRICAL PART LIST

Integrated Circuits

Reference Designator Description Part Number Note

U100, 106, 201, 202, 203, 306, 700

U101, 200, 300, 301 0P AMP QUAD, SOIC-14, U102, 103, 104, 105, 304, 305 OP AMP SWTCH, SOIC-8, U204 Q-TRANSCOND, SO-16, U302, 303 OP AMP, SNGL, SO-8, U500, 501 POWER AMP, AUDIO, U502, 503, 701 COMPARATOR, SOIC-8, U600 VOLT REG, 12V, 1A, POS, U601 VOLT REG, 12V, 1A, NEG,

OP AMP DUAL, SOIC-8, NJM4559

NJM2059 NJM2120 SSM2164S CA3080 TDA7294 NJM311M T0-220, LM 7812 T0-220, LM 7912

187473 4 187472 4 187474 4 187476

187617-001 4

170156 4 187477 4 116736

149009-12

Miscellaneous

Reference Designator Description Part Number Note

F600, 601, 602 FUSE, 4.0A, SLO BLO 177311-04000

3, 5

F600, 601, 602 FUSE, 3.15A, SLO BLO 177311-03150

3, 6

FC600A, 600B, 601A,601B, 602A, 602B

J1, 5 CONN, RT ANGLE, BEAU 177291-05 4 J12 CONN, HEADER, 5 POS 148591-05

J2, 3 CONN, HEADER, 8 POS 148591-08 4 J4 CONN, RT ANGLE, BEAU 177291-03 4

J400 CONN, HEADER, 3 POS 143965 J401 CONN, HEADER, 5.0MM,

J405, 407, 410, 501, 502, 605, 606 RES, JUMPER, 0Ω 139942 4, 5 J405, 407, 409, 410, 501, 502, 603 RES, JUMPER, 0Ω 139942 4, 6 J403, 404, 406, 410, 501, 605, 606 RES, JUMPER, 0Ω 139942 5 J403, 404, 406, 409, 501, 603 RES, JUMPER, 0Ω 139942 6

J6 CONN, SHIELDED, J6 (mate to female connector above) CONN, SHIELDED,

J6 CONN, SHIELDED, J6 (mate to female connector above) CONN, SHIELDED, (used with male connector above) LEVER, OPERATING, J6

FUSECLIP, 5MM 178548

191946-004

190693-008 4

FEMALE, 8 PIN

190694-008 4

MALE, 8 PIN

190693-004

FEMALE, 8 PIN

190694-004

MALE, 8 PIN

193501

CONNECTOR

ELECTRICAL PART LIST

Miscellaneous (continued)

Reference Designator Description Part Number Note

J600 CONN, HEADER, 2 POS 143963

J601 HEADER, HIGH

CURRENT, 8MM PITCH

J602 CONN, HEADER, INLINE,

PCB MNT, 5P

J7, 7B, 8, 8B CONN, HEADER, 12

POS, MALE

J9, 10 CONN, HEADER,

SHIELDED, 12 POS

K600 RELAY, 12V, DPST, 8A 191928

S1 SWITCH, SP, 3 POS,

VERT, SLIDE

S4, 5, 7 SWITCH, SPDT,

VERTICAL, SLIDE

S6 SWITCH, DPDT, 5A,

RIGHT ANGLE, SLIDE

VR600 VARISTOR, METAL

OXIDE, 275V, 75 JOULE

178742-5

133220-05

137489-12 4

170250 4

187482 4 187481 4 187480 170189

AMPLUS™ 50 AND 100 ACCESSORY NOTES

1. The AmPlus 50 and 100 Business Music Amplifiers MUST be used with the Power Amplifier Accessory Kits referred to in Figure 12. These kits supply the necessary parts to allow the amplifiers to be used in different countries. They include the literature kit, power cord, and remote volume control required for that voltage and configuration. The amplifiers themselves are also configured internally for use at 120 or 240 Volts.

2. The AmPlus 50 and 100 Amplifiers can be rack mounted using the optional rack-mount kit. Refer to Figure 16 for more information.

3. The AmPlus 100 Amplifier can use the optional Opti-Source™ and Opti-Voice

Page Option Cards to extend the abilities of the amplifier in different installations. These Option Cards will be covered more extensively in the supplement to this service manual (part number 194101-S1).

4. The AmPlus 100 Amplifier can be used with the optional CVT-100 Transformer Accessory Kit to allow 70/100V operation in both channels. Refer to Figure 15 for more information.

5. The AmPlus 50 and 100 Amplifiers can be used with optional Equalizer Cards to allow the

use of the Free Space

Model 1B Acoustimass® Module, and the Model 8, Model 25, and

Model 32 Loudspeakers.

Table 14. AmPlus 50 and 100 Amplifiers and Accessories

Item Description Product Code Part Number

Power Amplifiers AmPlus 100 120Vac 240Vac

017803 017804

187915-001

187915-002 Amplus 50 120Vac 240Vac

017805 017806

187921-001

187921-002 Power Amplifier Accessory Kits

US/Canada Europe Japan U.K. Australia

017989 017990 017991 017992 017993

187492-001

187492-002

187492-003

187492-004

187492-005 Rack Mount kit 019596 191909-001 Opti-Voice page option card 019073 187515-001 Opti-Source option card 019074 187505-001 CVT-100 Transformer accy kit 020743 193541-001 Model 1B EQ card 019509 190670-001 Model 8 EQ card 015134 184824-001 Model 32 (and Model 25) EQ card 011687 183744-001

PACKING LIST

Power Amplifier Accessory Kit (see Figure 12)

Item

Number

1 Carton, D/C, Accessory 177798 1 2 Feet, Chassis, kit, (4 feet) 187478 1

3 Sheet, Instruction, AmPlus™ 4 Line Cord, Detachable

US/Canada, 120V Europe, 220V Japan, 100V UK, 240V Australia, 240V

5 System Assy, Remote, BMS, Volume,

US/Canada Europe Japan UK Australia

6 Connector Kit, AmPlus 50,

AmPlus 100 188620-001 1

Description Part Number Qty. per

187957 1

173350 173352 181690 173351 173354

187491-1 187491-2 187491-3 187491-4 187491-5

Assy

1 1 1 1 1

Figure 12. Accessory Kit Packing Diagram

PART LIST

Remote Volume Control (see Figure 13)

Item

Number

Description Part

Number

1 PCB Assy, Rem, BMS, Volume 187983 2 Wallplate, RVC, (US, CA, AUS) 188611 2 Wallplate, No Switch, RVC, (EURO, UK) 188610 2

Cover, Remote, FreeSpace® 6 (Japan) 3 Knob, Remote, FreeSpace 6 (All Models) 178104 4 Screw, Mach, 6-32x1, .00, ovalhd (US/CA) 178115-16 4 Screw, Mach, M3, 5x25mm, Flat, XREC (EURO,

178116-25

UK, AUS, JAPAN) 5 Screw, Tapp, 6-13x.5, PAN, XREC 173555-08 6 Bag, Poly, 9.38x6x2 mil 100278 7 Carton, D/C, Interlock Kit, Cann 131843

178102

Figure 13. Remote Volume Control Exploded View

PACKING LIST

AmPlus™ 50 and 100 Amplifier (see Figure 14)

Item

Description Part Number Quantity

Number

1 LIT KIT, AMPLUS 50/100, contains:

BROCHURE, ALL PRODUCTS OWNER’S MANUAL DECLARATION OF CONFORMITY REGISTRATION CARD

191954 188898 190652 188657

180089 2 BAG, POLY, 15X28X4 MIL 187487-028 1 3 PACKING, CORNER BLOCK, EPP 187486 2 4 CARTON, AMPLUS, RSC 187489 1

1 1 1 1

ASSEMBLED AMPLIFIER

Figure 14. AmPlus Series Amplifier Packing Diagram

PART LIST

AmPlus™ 100 Amplifier Accessory Transformer (see Figure 15)

Item

Description Part Number Qty. per

Number

1 Autotransformer, Accy, 70/100V 193502 1 2 Enclosure, Top, Trans. 190662 1 3 Enclosure, Bottom, Trans 190661 1 4 Screw, Tapp, 4-24, Pan Head 190118-06 2 5 Screw, #8-32, Pan Head 190623-008 8 6 Nut, Hex, 8-32, Keps 100413-2 2 7 Carton Vendor Supplied 1 8 Manual, Owner's 193542 1

9 Poly Bag Vendor Supplied 1 10 Lever, Operating 193501 1 11 Connector, Male, sheilded 190694 1

Assy.

Figure 15. AmPlus 100 Accessory Transformer Exploded and Packing View

PART LIST

AmPlus™ 50 and 100 Amplifier Rack Mount Accessory Kit (see Figure 16)

Item Number Description Part Number Qty.

1 Bracket, Rack Mount 187962 2 2 Tube, Packing, with end caps 184177 1 3 Poly Bag vendor supplied 2 4 Instruction Sheet 191958 1

END CAP

Figure 16. AmPlus 50 and 100 Amplifier Rack Mount Accessory Kit

DEVICE PIN-OUT DIAGRAMS

IC, Volt Reg, 12V, Pos, TO-220  Pin 1. Input Pin 2. Ground Pin 3. Output

BCE

BOTTOM VIEW

123

Bose® P/N: 116736, LM 7812

BCE

BOTTOM VIEW

BCE

FRONT VIEW

Bose P/N: 117921, 2SC536

1 2

BCE

PIN FUNCTION 

1. BASE

2. EMITTER

3. COLLECTOR

Bose P/N: 119168, 2SA608 Bose P/N: 146819, MMBT3904

1 2

PIN FUNCTION 

1. ANODE

2. ANODE

3. CATHODE

1 2

PIN FUNCTION 

1. ANODE

2. ANODE

3. CATHODE

Bose P/N: 147239, BAV99 Bose P/N: 147249, BAV70

DEVICE PIN-OUT DIAGRAMS

PIN FUNCTION 

1. ANODE

2. NO CONNECTION

1 2

3. CATHODE

Bose® P/N: 148333, ZENER, 9.1V, SOT-23

PIN FUNCTION 

1. BASE

2. EMITTER

1 2

3. COLLECTOR

PIN FUNCTION 

1. ANODE

2. NO CONNECTION

1 2

3. CATHODE

Bose P/N: 148582, MMBD914LT1

IC, Volt Reg, 12V, Neg, TO-220  Pin 1. Ground Pin 2. Input Pin 3. Output

Bose P/N: 148596, MMBT3906

Bose P/N: 170214, GBU6 Rectifier

123

Bose P/N: 149009-12, LM 7912

PIN 1. BASE PIN 2. COLLECTOR PIN 3. EMITTER

123

Bose P/N: 172284, TIP141T

DEVICE PIN-OUT DIAGRAMS

PIN 1. BASE PIN 2. COLLECTOR PIN 3. EMITTER

3 4 5

6 7 8

123

Bose® P/N: 172285, TIP146T Bose P/N: 187472, NJM2059M

PIN FUNCTION 

1. A OUTPUT

2. A -INPUT

3. A +INPUT

4. V-

5. B +INPUT

6. B -INPUT

7. B OUTPUT

8. V+

-+ +-

4 5

14 13 12 11 10

PIN FUNCTION 

1. A OUTPUT

2. A -INPUT

3. A +INPUT

4. V+

5. B +INPUT

6. B -INPUT

7. B OUTPUT

8. C OUTPUT

9. C -INPUT

10. C +INPUT

11. V-

12. D +INPUT

13. D -INPUT

14. D OUTPUT

PIN FUNCTION 

1. SWITCH CONTROL

2. A +INPUT

3. A -INPUT

4. V-

5. OUTPUT

6. B -INPUT

7. B +INPUT

8. V+

Bose P/N: 187473, JRC NJM4559M

I-IN

VCA1

VCA2

VCA3

VCA4

POWER SUPPLY AND

BIASING CIRCUITRY

V+ GND

V- MODE

I-OUT

Bose P/N: 187476, SSM2162S

Bose P/N: 187474, NJM2120M

PIN CONFIGURATION 

1. MODE

2. I IN1

3. VC1

4. I OUT1

5. I OUT2

6. VC2

7. I IN2

8. GND

9. V-

10. I IN3

11. VC3

12. I OUT3

13. I OUT4

14. VC4

15. I IN4

16. V+

DEVICE PIN-OUT DIAGRAMS

Pin function

4 5

Bose® P/N: 187477, NJM311M Bose P/N: 187479-001 S2A SMD Diode



1. Gnd

2. + Input

3. - Input

4. V-

5. Bal

6. Bal/Strobe

7. Output

8. V+

CATHODE

ANODE

BCE

INV. INPUT

NON-INV.

INPUT

V-

V+

OUTPUT AMPLIFIER

BIAS INPUT

BOTTOM VIEW

BCE

FRONT VIEW

Bose P/N: 188634-001, J107Bose P/N: 187617, CA3080

DEVICE PIN-OUT DIAGRAMS

Pin Function

15 14 13 12 11 10

9 8 7 6 5 4 3 2 1

TOP-VIEW

15. -Vs (Power)

14. OUT

13. +Vs (Power)

12. N.C.

11. N.C.

10. MUTE

9. STAND-BY

8. -VS (Signal)

7. +VS (Signal)

6. Bootstrap

5. N.C.

4. SVR

3. Non-Inverting Input

2. Inverting Input

1. Stand-by Gnd.

IN-

IN+

IN+MUTE

MUTE

STANDBY

2 3

TDA7294

MUTE

STANDBY

STANDY GROUND

+Vs (signal)

-Vs (signal)

THERMAL

SHUTDOWN

+Vs (power)

SHORT-

CIRCUIT

PROTECTION

-Vs (power)

OUT

BOOT- STRAP

Bose® P/N: 170156, TDA7294

TROUBLESHOOTING TIPS

1. General Troubleshooting Procedures

1.1 These units are very flexible in regard to setup and operation, which means that it will be

much easier for the customer to install and/or setup the unit incorrectly. Be sure to check that the product was installed properly, and that all switches are in the correct positions for that particular usage. Refer to the AmPlus™ 50 and 100 Installation diagrams and the Amplifier Controls pages for more information.

1.2 The main circuit board is built with the surface-mounted IC's mounted on the underside of the board. There are several test-points located on the top of the PCB which are easier to access than the devices themselves, which can be used to troubleshoot down to a smaller area before probing on the bottom of the board is necessary. Refer to the appropriate schematic diagram, and look for the diamond shape near the signal paths. These points are silk-screened on the top of the PCB and labelled as TS2, TS3, etc. Refer to the PCB layout diagrams for more information.

1.3 If you need to operate the unit with the PCB in the upright position, you must connect a ground wire from the unit chassis to one of the ground points on the PCB for proper operation.

2. Hum and noise problems

2.1 If the customer is experiencing hum and/or noise problems, check to make sure the

following installation guidelines were met.

• Connect high impedance units, such as tape players and CD players, to the amplifier

with shielded, single conductor cable. Keep cable lengths less than

10 feet (3 meters).

• Use twisted shielded pairs on microphone inputs.

• Keep input cables away from:

-Loudspeaker cables to prevent inductive feedback.

-Power lines or transformers.

• For output loudspeaker connections, Class II wiring is suggested. Use standard

#16 AWG wire. Keep loudspeaker cables away from power cables.

AmPlus™ 50 and AmPlus 100

Business Music Amplifiers

® ®

1997 Bose Corporation

Service Manual

Part Number 194101 Rev. 00

SPECIFICATIONS AND FEATURES SUBJECT TO CHANGE WITHOUT NOTICE

® ®

Bose Corporation The Mountain Framingham, Massachusetts USA 01701

P/N: 194101 Rev.00 11/97 FOR TECHNICAL ASSISTANCE OR PARTS ORDERS, CALL 1-800-367-4008

BOSE AMPLUS 50, AMPLUS 100 Schematic

Specifications and Main Features

Frequently Asked Questions

User Manual