UAM4SYS • 1
Ramsey Electronics Model No. UAM4SYS
The UAM4SYS is a state of the art audio amplifier that utilizes a class
D power amplifier. Professional balanced input is provided along with
an unbalanced line output that can be configured as a buffered input
feed thru or as the “processed”, (tone, balance, level) signal to feed
remote locations. All controls use DC or digital levels, eliminating
control noise. Headphone level is provided by a 64 step digital
control with memory. Automatic over temperature protection and
power stage mute is provided. All this in a rugged compact
aluminum case.
UNIVERSAL
AUDIO AMPLIFIER
SYSTEM
FEATURES
• 42 watt class D amplifier (21W per channel stereo mode)
• 0.1% + N distortion
• Balanced or unbalanced inputs
• All DC or digital controls for noise free operation
• Selectable direct or processed (bass, treble, balance, level, loudness) line
outputs
• Pre-mute headphone output
• 64 step digital headphone level adjustment with level memory
• Operates on 12 to 18VDC @ 3.3A max power input (up 87% efficient)
• Quick connect spring terminal output terminals accept 28AWG to 14AWG
wire
• Selectable 22, 25, 29.5 or 36dB gain
• Rugged shielded aluminum case
• Compact profile (5.6in x 6.6in x 1.6in) weighs in at 1.24 lbs (excluding
power supply)
UAM4SYS • 2
PARTIAL LIST OF AVAILABLE KITS:
RAMSEY TRANSMITTER KITS
• FM10C, FM25B FM Stereo Transmitters
• AM1C, AM25 Transmitter
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• FR1C FM Broadcast Receiver
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RAMSEY HOBBY KITS
• SG7 Personal Speed Radar
• SS70C Speech Scrambler/Descrambler
• TT1CTelephon e Recorder
• MD3C Microwave Motion Detector
• PH14C/15C/16C Peak hold Meters
RAMSEY AUDIO KITS
• SHA1C and SHA2 Headphone Amplifier kits
• UAM4 40 Watt Stereo Amplifier kit
RAMSEY AMATEUR RADIO KITS
• HR Series HF All Mode Receivers
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• CW7C CW Keyer
• QRP Power Amplifiers
RAMSEY MINI-KITS
Many other kits are available for hobby, school, scouts and just plain FUN! New
kits are always under development. Write, call or visit www.ramseykits.com for
our free Ramsey catalog.
UAM4SYS
Ramsey Electronics publication No. UAM4SYS, Rev. 3.4a
First Printing, October, 2008
This Printing, June, 2010
COPYRIGHT 2008-2010 by Ramsey Electronics, LLC, 590 Fishers Station Drive, Victor, New
York 14564. All rights reserved. No portion of this publication may be copied or duplicated without
the written permission of Ramsey Electronics, LLC. Printed in the United States of America.
UAM4SYS • 3
Universal Audio
Amplifier System
Ramsey Publication No. UAM4
Manual Price Only $5.00
TABLE OF CONTENTS
Theory of Operation........................................... 4
“Learn-As-You-Build” Kit Assembly..................11
Parts List.......................................................... 13
Assembly Steps................................................14
Setup and Testing ............................................24
Specifications ...................................................36
Schematics..................................................38-41
Parts Layout Diagram.......................................42
Ramsey Kit Warranty........................................43
KIT ASSEMBLY
AND INSTRUCTION MANUAL FOR
RAMSEY ELECTRONICS, LLC
590 Fishers Station Drive
Victor, New York 14564
Phone (585) 924-4560
Fax (585) 924-4555
www.ramseykits.com
UAM4SYS • 4
UAM4SYS Theory of Operation
Note: There are four pages of schematics included in this manual. Please
refer to them as directed as you read the following.
Power Supply
Since electronic equipment doesn’t work without power, lets start off by
describing the UAM4SYS power supply. For reference when reading this
section, check schematic sheets 1 and 2 (pages 38 & 39). The UAM4SYS
requires a 12 to 18 volt DC input at 3.3 amps applied to Power jack J5. From
there the power goes two directions. First, to VR1, a 7810 positive 10 volt 1
amp regulator. C28 filters the regulator’s output. 10 Volts is used to power
most of the circuitry you see in schematic 1, as well as the 5 volt power
supply on schematic sheet 2. Since the regulator is before the power switch,
all circuits powered by the 10 volt are powered as soon as the unit is plugged
in. On schematic sheet 2, regulator VR2, a 7805 positive 5 volt 1 amp
regulator that powers circuitry on schematic sheets 1, 2, and 4. C39 filters
VR2’s 5 volt output.
Turn back to schematic sheet 1. The second place the input power is routed
to the power switch, S1. When this switch is turned on, power is applied to
the power amp IC, U7 on schematic page 4. It is also applied to R29 through
J6 pin 10 to J40 pin 1 on the front panel (schematic sheet 3). This causes
D4, the power indicator LED, to light.
An interesting note is that because the 10 volt and 5 volt circuits are active
whenever the power supply is plugged in, you can listen to the input signal
on the headphones and the line outputs will be active even though the power
switch is off. The operation of these sections is discussed in detail in the
following sections. I’m sure you can think of some interesting applications for
this ‘feature!’
Input Buffer
IC U1 contains 4 operational amplifiers, (op amp). U1A and U1B are set up
as a buffer with unity gain. C5, C10, C11, and C12 are input coupling
capacitors. They provide DC isolation between the input audio device and
the UAM4SYS. R11 and R14 provide a 5 volt bias to the op amp buffers.
Because the input can be a balanced signal and there is neg ative feedback
applied to the ‘-‘ input of U1A and U1B, R1, R15, R23 and R24 are
necessary to isolate that feedback signal from the applied input signal. A
resistor is needed on both the ‘+’ and ‘-’ inputs because the signal is
balanced. C47 provides filtering of any signal that might try to sneak thru to
the power supply and therefore assures a stable reference bias on the op
amp input.
UAM4SYS • 5
The input buffer allows both unbalanced and balanced input sig nals to be
applied to the UAM4SYS. First we will take an unbalanced signal into the
unbalanced input at J4.
An unbalanced single is one that uses two conductors, one for the audio
signal and one for ground. This is the type of signal that comes out of an
MP3 player, CD player, tape deck, VCR, computer, or other similar device.
J4 takes a 3.5mm Stereo plug. A 3.5mm stereo plug consists of three
conductors called tip, ring, and sleeve. The tip at the very end of the plug is
normally the left audio channel. The next conductor down is called the ring
and is normally the right audio channel. The last and biggest cond uctor is
called the sleeve and is the ground connector that is common to both the left
and right channels.
Now that we know what a 3.5mm stereo plug is lets follow an unbalanced
signal from the connector through the Input Buffer. When a plug is inserted
into J4 the electrical connections between pins 2 & 4 and 1 & 3 are opened.
The left channel signal from the tip enters J4 pin 2 through C10 and R1 to
U1A’s non-inverting input at pin 3. The left channel signal is buffered and
exits at pin1. The right channel signal from the ring enters J4 pin 1 though
C11 and R23 to U1B’s non-inverting input at pin 5. The right channel signal
is buffered and exits at pin 7. Ground comes in on the sleeve and is
connected to the circuit board ground plane.
A little information about balanced signals is probably a good idea at this
time. Balanced audio signals use three conductors, positive, negative, and
ground for each channel. The actual signal is not referenced to ground but is
applied on the ‘+’ and ‘-’ lines. The signal on the ‘+’ line is exactly the
opposite of the ‘-’ line. The two signals are applied to the two amplifier inputs
and the amplifier uses both of these to produce an output. The ground is
simply there to provide some shielding of the cable and is not used in any
other way. Most noise that sneaks onto the lines will be the same level, both
in amplitude and polarity at any given time. Since it is applied to the opposite
polarity inputs the noise will be canceled and not appear at the output. This
is called common mode rejection, a big advantage of the differential inputs of
the op amps. Balanced lines are used in most professional equipment and
for long signal runs.
For separate unbalanced inputs we will again use a 3 . 5mm stereo plug but
now we need one for each channel. When a plug is inserted into J2 and J3
the electrical connections between pins 2 & 4 and 1 & 3 of these jacks are
opened. Let’s follow the right channel and leave the left channel to you. The
positive tip signal enters J2 pin 4 goes to J4 pin 3 which is connected to pin 1
(no plug in J4). From J4 pin 1 the signal goes through C11 an d R23 to U1B’s
non-inverting input at pin 5. The negative ring signal enters through J2 pin 1
UAM4SYS • 6
and goes through C12 and R15 to U1B’s inverting input at pin 6. The right
channel signal is buffered and exits at pin 7.
J2 and J3 can also be used as unbalanced inputs by simply connecting an
unbalanced input to the connector tip and the ground to the ring and sleeve.
The signal will now be applied to the ‘-’ input of the op amps and the op amp
‘+’ inputs will be tied to ground. This is handy if you have inputs that use
separate left and right cables and mono 3.5mm plugs. Also, when usin g the
UAM4SYS in mono mode only the right channel, J2, input is used for mono
operation. Again this can then be used either balanced or unbalanced.
From the output of the input buffer the left and right audio signals go to two
different places. First they go to the line output buffer input headers H1 and
H2. They also go to the tone, volume, balance control IC, U3.
Tone/Volume/Balance
U3, an LM1034, provides tone, volume, balance, and loudness control for both
channels of the UAM4SYS. The IC supplies a DC reference voltage for the
bass, treble, balance, and volume controls. These controls are adjusted by
the user and provide individual DC levels to the IC where they set appropriate
levels of each function. Because DC levels are used to control the various
functions the scratchy noise produced by the controls in many audio
components is not a problem in the UAM4SYS.
C15 and C21 set the treble operation points. C19 and C20 set the bass
operation points. C18 and C16 are bypass capacitors for the IC. C6, C7, C8,
and C26 act as filters for the DC control lines. R17, R18, R19, and R20 (sheet
3) are the control potentiometers. R5, R6, R8, and R13 provide isolation
between the control pots and the IC. If you wish to learn more about how the
LM1034 actually works and how component values were selected do an
internet search on National Semiconductor and download the data sheet.
The unprocessed audio enters U3 pins 2 and 19 from the input buffers
through C9 and C4 which are coupling capacito rs. The audio is then
processed according to the settings of the control potentiometers and fed to
the right channel output at pin 8 and left channel output at pin 13. From here
the processed audio goes three places the line output buffer headers H1 & H2
(sheet 1), headphone amp (sheet 2), and power amp (sh eet 4).
Loudness
The loudness function is turned on when U3 pin 7 is connected to U3 pin 12.
It is turned off when U3 pin 7 is connected to U3 pin 17. Loudness is
controlled by front panel switch S4 (sheet 3) which controls U5A and U6 as
described below.
UAM4SYS • 7
U5A is a flip flop set up in the toggle mode. Its outputs at pin 6, called ‘Q’, and
pin 7, called ‘Q not’ indicated by a line over the Q symbol, are opposite DC
levels of either +5 volts or 0 volts. R27 is a pull up resistor for the flip flop’s
set line. C32 delays the +5 volts to U5A’s set line ensuring it comes up in the
set condition, which is +5V on output ‘Q’ at pin 6 and 0V on pin 7, ‘Q not’,
when power is first turned on. When S4 is pressed it applies a ground to C31
(sheet 2) causing C31 to discharge. When the button is released the ground
is removed from C31 and it charges through R38 to +5 volts. This positive
transition causes U5A to change states, (flip flop). An interesting thing to
know is when a switch opens or closes it usually has proble ms and may
actually open and close many times before finally ending up in it’s final state.
This is called switch bounce and is actually ‘seen’ by logic circuits like U5 and
causes unpredictable results. C31 and R38 help prevent these ‘bounces’ from
getting to U5 and is called de-bouncing.
U6 is called an analog switch. It contains 4 electronic switches, we’ll only be
using 2 of them that are turned on and off by signals applied to pins 7 and 13.
With +5 volts on these pins it’s associated switch is turned on and 0 volts
turns it off. With U5 Pin 6 at +5 volts U6 pin 13 is also at +5 volts. This
causes the switch between U6 pins 1 and 2 to close. At the same time U5 pin
7 is at 0V. This applies 0V to U6 pin 5 which causes the switch between U6
pin 3 and 4 to open. This turns off the Loudness function as mentioned
above. When S4 is pressed and released, U5A toggles causing pin 6 to
change to 0V and pin 7 to change to +5V. This places 0V on U6 pin 13
opening the switch between pins 1 and 2. It also places +5 V on U6 pin 5
closing the switch between pins 3 and 4 and turns off the loudness function.
Since pin 7 is +5V, power is applied to the loudness LED on the front panel
(sheet 3) through current limiting resistor R28 which lights the LED indicating
the UAM4SYS is muted.
Line Output Buffer
With headers H1 and H2 the user can select either processed (from U3) or
unprocessed (directly from input buffers U1A and U1B) audio to be sent to the
line outputs. R4 and R30 set the bias to ½ supply voltage (+5 volts) while
isolating the bias voltage from the power supply. R32 and R33 are pull-up
resistors which prevent oscillations that can be caused by external load
capacitance. C13, C14, C17, and C30 are coupling capacitors. The selected
right channel audio signal enters through the header pin 2 and i s applied to
the op amp buffer through C14. The output at U1 pin 8 is applied to the right
line output RCA connector through C17. The left channel is identical to the
right.
Notice that the signal to the line output buffer is before the mute function
which will be discussed in the ‘Power Amp’ description. This means that even
though the amplifier is muted the input signal will be present on the line output
UAM4SYS • 8
jacks. Therefore if you are using the line outputs to record a program you can
mute the speakers but continue to record the input. If you are feeding another
amplifier the mute function on the UAM4SYS will silence only the local
amplifier output.
Headphone Amplifier
U11 and U12 (sheet 2) are 750mW headphone ampli f iers. C45 is a power
supply filter capacitor. C33, C37, C34, and C38 are coupling capacitors. C35
and C36 are bypass capacitors. U10 is a digital potentiometer that provides a
DC level output at pin 6 that controls the gain of U11 and U12. S5 and S6
(sheet 3) are used to increase or decrease this DC level.
To increase the gain of the headphone amps S6 is pressed. This place s a
ground on pin 2 of U10. This high to low transition tells the IC to increase the
output voltage (pin 6) 1/64 of the +V to –V voltage (5 volts). If S6 is held down
for more that one second the output voltage will go another 1/64 step every
100 milliseconds until it is released or the full +5 volt level is reached. The
output voltage is applied to the volume control, pin 4, of U11 and U12. The
down button S5 functions just like S6 except the voltage is decreased. The
really neat thing about U10 is that it remembers where it is set even when the
power is removed. So if you turn off the UAM4SYS and then turn it back on
the headphone level will be where you left it. Also notice that the signal to the
headphones is before the mute function, just like the line output signals, which
will be discussed in the ‘Power Amp’ description. This means that even
though the amplifier is muted you can still hear the input signal. Therefore you
can make sure the correct program is ready to go before you apply it to the
speakers for everybody else to hear.
The right channel audio from the Tone/Volume/Balance IC, U3, is applied to
U12 through C38. The signal is amplified and fed to headphone jack J20
through C34.
Power Amp
The Power Amp U7 a MAX9708, is a class D amplifier. The letter D is simply
the next letter after C, and does not stand for digital. Class D and Class E
amplifiers are sometimes mistakenly described as "digital" because the output
waveform superficially resembles the pulse-train of a digital signal, but a Class
D amplifier merely converts an input waveform into a continuously pulse-width
modulated (square wave) signal. A digital waveform would be pulse-code
modulated.
Class D amplifiers are much more efficient than Class AB power amplifiers. As
such, Class D amplifiers do not need large transformers and heavy heat sinks,
which mean that they are smaller and lighter in weight than an equivalent
UAM4SYS • 9
SETUP AN
Class AB amplifier. All power devices in a Class D amplifier are operated in
on/off mode. The term usually applies to devices intended to reproduce
signals with a bandwidth well below the pulse switching frequency which in
our case is about 200kHz.
The MAX9708 converts the input signal to a sequence of pulses whose
averaged value is directly proportional to the instantaneous amplitude of the
signal. The frequency of the pulses is typically ten or more times the highest
frequency of interest in the input signal. The pulse frequency in the Power
Amp is around 200kHz or 10 times 20kHz. The output of such an amplifier
contains unwanted spectral components (that is, the pulse frequency and its
harmonics) which must be removed by a passive filter. The resulting filtered
signal is then an amplified replica of the input. This filtering is handled by the
patented technology of the Maxim MAX9807 amplifier chip and the speaker.
The design uses a unique filterless modulation and spread-spectrum switching
mode. This eliminates the need for large inductors and capacitors on the
output.
Typical class D amplifiers use a simple modulation method called ‘FixedFrequency Modulation’ (FFM). This simply means that a switching frequency
is selected and that is the frequency at which the output is switched. The
MAX9708 can use this method but it also has a special method called
‘Spread-Spectrum Modulation’ (SSM). With this method the switching
frequency is actually changed around a center frequency, in this case +- 4%
around 200kHz. Using this method the MAX9708 is able to reduce the noise
generated with typical class D amplifiers and the need for large filters
described above is minimized. How this is accomplished is beyond this
manual. If you are interested you can find information on the web by
searching for ‘spread spectrum’ and also check out the Maxim web site at
“www.maxim-ic.com” and go to the data sheet for the MAX9708.
The main advantage of a class D amplifier is power efficiency. Because the
output pulses have a fixed amplitude the output devices, which are MOSFETS
in the case of the MAX9708, are switched either on or off rather than operated
in linear mode. This means that very little power is dissipated by the
transistors except during the very short interval between the on and off states.
The MAX9708 is capable of achieving up to 87% efficiency. The wasted
power, the remaining 13%, is low because the instantaneous powe r dissipated
in the transistor is the product of voltage and current, and one or the other is
almost always close to zero. The lower losses permit the use of a smaller heat
sink while the power supply requirements are lessened too.
The input signal(s) are applied to U7 though C57 and C59. Once the signal
reaches the MAX9708 there isn’t a lot more to say other than it amplifies the
signal and applies it to the output terminals at T1.
UAM4SYS • 10
The ‘GAIN’ jumpers, H4 and H5, are used to adjust the gain of the MAX9708.
See the tables on the schematic for specific settings. The gain settings are
also printed on the UAM4SYS circuit board next to the jumpers.
The ‘MUTE’ input terminal located below the left and right channel inputs is
used to place the UAM4SYSinto the mute mode. The mute mode causes the
output transistors to stop switching. This may be used to silence the
UAM4SYS with the advantage of a built in click/pop suppression feature of the
MAX9708. Shutdown mode reduces the power consumption of the
UAM4SYS to a very low level, about 0.1uA. This is handy for battery operated
applications to increase battery life. The mute function is controlled by the
second half of flip flop IC U5. This circuit operates in exactly like the flip flop
used for the loudness function with the exception that the ‘Q’ output on pin 10
is connected to the power amplifier, U7 pin 31, instead of controlling an analog
switch. U7 is muted when the ‘Q’ output is low, 0 volts. Note that the mute
function only controls the output of the speaker output. It will not have any
effect on the headphone or line outputs of the UAM4.
The UAM4SYS may be operated as either a 2 channel, 21 watt per channel,
or a single 42 watt amplifier. The mode of operation is determined by header
jumper H3 and the placement of jumpers at L+, L-, R+ & R- located near the
output terminals. With no jumper installed on H3 the MAX9708 is in 2 channel
or stereo mode. This means that it is operating like two separate amplifiers.
In this mode there should be no jumpers installed at the L+, L-, R+, & Rpoints.
DO NOT INSTALL ANY JUMPERS AT L+, L-, R+, & R- WHEN NO JUMPER
IS INSTALLED AT H3
If a jumper is installed at H3 the MAX9708 will operate in mono mode. In this
mode only the signal applied to the right channel input is used. You may use
the UAM4SYS as either a single 42 watt amplifier if are installed between L+
& R+ and between L+ & R-. If jumpers are not installed between L+ & R+,
and between L+ & R-, the UAM4SYS will operate as two 21 amplifiers with the
same input signal.
Note that even though it appears you could connect the left and right speaker
outputs together at a point away from the UAM4SYS
DO NOT ATTEMPT THIS!!!
Connections away from the board may cause signal phasing differences and cause
damage to your UAM4SYS.
UAM4SYS • 11
That’s about it. The rest of the components are simply support components
required by the MAX9708 and are used to provide stable voltages and signals
generated within the MAX9708. Again if you want more in depth information
about the MAX9708 go to “www.maxim-ic.com” and locate the data sheet for
it.
RAMSEY Learn-As-You-Build KIT ASSEMBLY
Successful kit assembly requires close attention to the assembly the assembly
instructions, good soldering techniques and proper tools. Here are some
helpful suggestions.
• Use a 25-watt soldering pencil with a clean, sharp tip.
• Use only rosin-core solder intended for electronics use .
• Use bright lighting; a magnifying lamp or bench-style magnifier may
be helpful.
• Do your work in stages, taking breaks to check your work. Carefull y
• brush away wire cuttings so they don't lodge between solder
connections.
We have a two-fold "strategy" for the order of the following kit assembly steps.
First, we install parts in physical relationship to each other, so there's minimal
chance of inserting wires into wrong holes. Second, whenever p ossible, we
install in an order that fits our "Learn-As-You Build" Kit building philosophy.
This entails describing the circuit that you are building instead of just blindly
installing components. We hope that this will not only make assembly of our
kits easier, but help you to understand the circuit you’re constructing. For
each part, our word "Install" always means these steps:
1. Pick the correct part value to start with.
2. Place it in the correct PC board location.
3. Orient it correctly, follow the PC board drawing and the written
directions for all parts - especially when there's a right way
and a wrong way to place it on the board. (Diode bands, electrolytic
capacitor polarity, transistor shapes, dotted or notched ends
of IC's, and so forth.)
4. Solder all connections unless directed otherwise. Use enough heat
and solder flow for clean, shiny, completed connections.
UAM4SYS • 12
SURFACE MOUNT COMPONENT SOLDERING INSTRUCTIONS:
You’ll notice that the circuit board contains only a few holes for component
leads to pass through. This is because the SMT components will be affixed to
the TOP side of the PC board, the side with the white printing. Be aware that
the component view for assembly is looking at the TOP side of the PC board.
Patience is the key when installing surface mount components. Typically, the
first step (after identifying the component) is to “tin” one of the PC traces that
will connect to the part. Once this is accomplished, the part can be installed by
holding it with tweezers in contact with the “tinned” trace and re-heating the
solder (see the following diagrams). Another commonly used technique is to
glue the surface mount components to the printed circuit board before
soldering. The procedure is to take a small amount of glue (usually with a pin
or toothpick) and “dab” the circuit board in the place where the component will
be affixed. Be careful not to apply too much glue as when the part is placed it
may “squash” the glue underneath the soldering tabs of the component.
Carefully place the part into position, and when the glue dries, solder the
connection.
UAM4SYS • 13
UAM4SYS PARTS LIST
Sort and “check off” the components in the boxes provided. We do our best to
pack all our kits correctly but it is possible that a mistake has o ccurred and we
missed a part. Please note that physical descriptions of parts are for those
currently being shipped. Sometimes the parts in your kit may have a different
appearance but still have the same values. Do not separate Surface Mount
parts from their packaging until installation.
CAPACITORS
3 0.01uF Ceramic Disk [marked 103] (C3, 15, 21)
8 0.1uF Ceramic Disk [marked 104] (C24, 31, 40, 41, 42, 44, 46, 47)
8 0.22uF Ceramic [marked 224] (C6, 7, 8, 23, 26, 32, 37, 38)
2 0.39uF Metal Film [marked 394] (C19, 20)
2 1uF Electrolytic [marked 1uF] (C35, 36)
18 10uF Electrolytic [marked 10uF] (C4, 5, 9, 10, 11, 12, 13, 14, 16, 17,
18, 22, 28, 29, 30, 39, 45) {extra included to make test jig}
2 100uF Electrolytic [marked 100uF] (C33, 34)
1 1000uF 25Volt Electrolytic [marked 1000uF 25V] (C1)
4 47uF Tantalum SMT [marked 476] (C48, 50, 60, 62)
Preinstalled
1 0.01uF Ceramic 0805 SMT [not marked] (C53) Preinstalled
4 0.1uF Ceramic 0805 SMT [not marked] (C49, 51, 55, 61) Preinstalled
4 0.001uF Ceramic 0805 SMT [not marked] (C25, 27, 43, 63)
Preinstalled
5 1uF Ceramic 0805 SMT [not marked] (C54, 56, 57, 58, 59)
Preinstalled
1 4.7uF tantalum 1210 SMT [not marked] (C52) Preinstalled
RESISTORS
2 150 ohms [marked Brown, Green, Brown] (R34, 35)
2 1 K ohms [marked Brown, Black, Red] (R32, 33)
7 2.2 K ohms [marked Red, Red, Red] (R21, 22, 27, 28, 29, 37, 38)
4 10 K ohms [marked Brown, Black, Orange] (R1, 15, 23, 24)
4 47 K ohms [marked Yellow, Violet, Orange] (R5, 6, 8, 13)
2 470 K ohms [marked Yellow, Violet, Yellow] (R11, 14)
2 1M ohm [marked Brown, Black, Green] (R4, R30)
4 10 K ohms Potentiometer [marked B10K] (R17, 18, 19, 20)
1 4.7 K ohms SMT 0805 [marked 472] (R2) Preinstalled
1 2.2 K ohms SMT 0805 [marked 222] (R7) Preinstalled
2 10 K ohms SMT 0805 [marked 103] (R3, 9) Preinstalled
SEMICONDUCTORS
4 LED [red] (D1, 3, 4, 5)
1 LMC660AIN [marked LMC660AIN] (U1)
1 LM1036N [marked LM1036N] (U3)
UAM4SYS • 14
1 74HC109 [marked 74HC109] (U5)
1 CD4066DCN [marked CD4066] (U6)
1 DS1669 [marked DS1669] (U10)
1 7810 [marked 7810] (VR1)
1 7805 [marked 7805] (VR2)
1 MMBT3906 [marked 2A] (Q3) Preinstalled
2 LM4875M [marked LM4875M] (U11, 12) Preinstalled
1 MAX9708 [marked MAX9708] (U7) Preinstalled
MISCELLANEOUS
4 3 Pin Header (H1, 2, 4, 5)
1 2 Pin Header (H3)
2 RCA Jack (J1, 8)
4 3.5 mm Phone Jack (J2, 3, 4, 20)
1 2.1 mm Power Jack (J5)
2 10 Pin Dual In-Line Connector (J4 0, J7)
1 DPDT Push Button Switch (S1)
4 SPST Momentary Push Button Switch (S2, 4, 5, 6)
1 4 Pin Wire Locking Connector (T1 )
5 Jumper Blocks
1 5” length of 18 gauge wire.
4 Ferrite bead filter SMT 805, 600 ohms@100MHz(L1, 2, 3, 4)
Preinstalled
HARDWARE
6 Beryllium Grounding Fingers
1 Push Button Cover
4 Knobs.
ASSEMBLY
We will begin with the main board oriented in the direction shown. Be sure not
to confuse the side of the board where the parts go. On the board you will see
the side that has white silk screen parts locations. This is the side where most
parts are mounted. We will begin with lower profile parts and wo rk up to the
higher ones in each functional section. Don’t use sockets for integrated
circuits (IC’s).
In this day of miniaturization not all parts are made in the familiar through-hole
style packages (a part with leads that go through the circuit bo ard and are
soldered on the board’s back side). Some of these parts come in surface
mount or SMT packages (parts that are soldered on the same side of the
circuit board they mount on). An example of this is the MAX9708 Class D 40
watt audio amplifier IC (U7) used in this kit. Since SMT parts are normally
small they can be difficult or impossible to install by hand, so we have installed
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