Ashly FTX-1001, FTX-2001, FTX-1501, CFT-1800 User Manual

FTX-1001
FTX-1501
FTX-2001

CFT-1800

Power Amplifier

Series III

Operating Manual

ASHLY AUDIO INC.

847 Holt Road Webster, NY 14580-9103 Phone: [phone]

Toll-Free: [phone] Fax: [phone] Inter net: http://www.ashly.com/

Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

Table Of Contents

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 AC POWER REQUIREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1 AC Voltage Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.2 Current Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.3 AC Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4 CABLE REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.1 Input Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.2 Output Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5 RACK-MOUNTING REQUIREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.1 Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.2 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.3 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

6 FRONT PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.1 Power Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.2 Thermal Status Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.3 Output Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.4 Clipping Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6.5 Protect Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7 REAR PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7.2 Normal/Bridging Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7.3 Stereo/Parallel Mono Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7.4 Level Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7.5 Speaker Outputs - Binding Posts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8 INPUT OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.1 Input Isolation Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.2 Peak Limiter Compressor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.3 Two-Way Crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8.4 Mic-Line Mixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

9 TYPICAL APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9.1 Stereo Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9.2 Parallel Mono Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9.3 Bridged Mono Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

10 DESIGN THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1 1 TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.1 No Audio Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.2 Distorted Sound. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

11.3 Hum or Buzz Noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

12 DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

13 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

14 WARRANTY POLICY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

15 SCHEMATICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Caution:

This power amplifier can produce dangerous output
voltage levels, high power levels, and high sound pressure
levels in loudspeakers. In order to minimize the risk of
injury, damage, or hearing loss, please read the entire
owner's manual before connecting to a sound system.

WARNING:

THIS APPARATUS MUST BE EARTHED

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

1. INTRODUCTION

The Ashly FTX Series III MOSFET amplifiers
combine the sonic excellence of a high-end stereo amp
with the ruggedness and stamina necessary in pro audio.
The FTX Series III amps use lateral power MOSFETs
(metal-oxide-semiconductor, field-effect transistors) for
their superior audio fidelity and unmatched reliability as
proven in Ashly amps for over fifteen years. These
MOSFET output devices exhibit many superior perfor­mance characteristics over the conventional bipolar power
transistors used in most conventional power amp designs.
They are inherently self-regulating and do not exhibit
many of the failure modes of bipolar transistors.

MOSFETS have no thermal runaway tendency so
the need for temperature tracking bias circuitry is elimi­nated, making the design simpler and more reliable.

MOSFETS do not suffer from secondary break­down (the primary failure mechanism in in bipolar tran­sistors which requires complex dissipation limiting to
avoid.) The MOSFET will even withstand a shorted load
and self-limit the resulting high drain current without any
protection circuitry for a short time.

MOSFETS do not have a “minority carrier stor­age time” (a phenomenon found in bipolar transistors in
which a certain amount of time is required to turn the
transistor off). Therefore the MOSFET is said to be a
“fast” device which can function very accurately and ef­ficiently with high amplitude/high frequency signals and
transient waveforms.

The FTX series III amplifiers are the result of
years of refinement to the original Ashly MOSFET de­sign. The current circuit is cleaner, quieter, and more
stable than ever before. A number of improvements have
been made in the area of thermal management using new
insulating materials and increased heatsink area, allow­ing even more robust performance into difficult loads.
Protective systems have been refined to add even more
insurance against gross faults such as short circuits and
the application of speaker damaging signals to the ampli­fier. The module assembly is produced using assembly
techniques including individual testing of each compo­nent before it is placed on the PC board, and a state-of­the-art soldering system which insures excellent strength
and ruggedness.

improved power handling, and better matching. The all­metal case of these transistors results in a ruggedness not
possible with plastic designs.

The unmatched reliability of the power MOSFET
output devices, the clever mechanical design, and the
careful assembly techniques of the FTX Series III ampli­fiers ensure years of maintenance-free service.

2. UNPACKING

As a part of our system of quality control, every
Ashly product is carefully inspected before leaving the
factory to ensure flawless appearance. After unpacking,
please inspect for any physical damage. Save the ship­ping carton and all packing materials, as they were care­fully designed to reduce to minimum the possibility of
transportation damage should the unit again require pack­ing and shipping. In the event that damage has occurred,
immediately notify your dealer so that a written claim to
cover the damages can be initiated.

The right to any claim against a public carrier
can be forfeited if the carrier is not notified promptly and
if the shipping carton and packing materials are not avail­able for inspection by the carrier. Save all packing mate­rials until the claim has been settled.

3. AC POWER REQUIREMENTS

3.1 Voltage Requirements

Your FTX Series III amplifier is supplied with a
three conductor grounded AC power cord, and should be
plugged into a standard 3-wire grounded electrical outlet
which supplies 120VAC 50-60 Hz (some export models
are wired for 100 or 240 volts and are labeled as such).
In the event of line voltage sag, or “brown-out”, FTX
Series III amplifiers will continue to operate normally,
albeit with less power.

3.2 Current Requirements

A 15 amp circuit is sufficient for normal opera­tion down to 2Ω loads. The actual AC current consump­tion by the amplifier depends greatly on the audio signal
and the load impedance. For typical audio program ma­terial with the amplifier driving both channels just peak­ing at the clipping level, the following AC line current
capacities are recommended for system design purposes:

The FTX series III uses the latest generation of
lateral MOSFETS. These components also improve on a
time honored design. The result is higher bandwidth,

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

FTX-1001 FTX-1501 FTX-2001

Idle .5A .6A 1.5A
8Ω loads 2 Amps 2.5 Amps 3.5 Amps
4Ω loads 3 Amps 4 Amps 6 Amps
2Ω loads --- 7 Amps 10 Amps

Table 3.1: Recommended AC line current capacity

All FTX Series III amplifiers consume less than

12 amps when operating at 1/8 power into 2Ω loads. This

condition satisfies the UL, CSA and building electrical

code requirements for a piece of audio equipment not to

consume more than 80% of the current available when

plugged into a grounded 15 amp outlet and operated

at 1/

8 of maximum power.

3.3 AC Grounding Requirements

To reduce the risk of ground loop hum, all sys­tem ground references should originate at the same point
in your AC power distribution. Never remove the
amplifier’s ground pin as it is both unlawful and danger­ous, creating a potential shock hazard.

Since power at the speaker load is a primary con­cern in system design, we have included a table to best
determine appropriate wire gauge for your application.
Table 4.1 lists the percentage of the speaker load power
which would be lost in an arbitrary 100 ft run of 2-con­ductor cable. This table expresses the power loss as a
percentage of the load’s power rather than the total am­plifier output power, so that you can use this table to ac­curately determine power loss to the load at other cable
lengths. For example, if you plan to deliver 100 watts to
an 8Ω load through 50 ft of 14 ga. cable, the power loss
in the cable would be 3.2% ÷ 2 = 1.6% of 100 watts or

1.6 watts lost in the cable. Table 4.1 also gives the resis­tance per 100 feet of common copper wire gauges.

Wire Gauge Ω/100ft 8Ω load 4Ω load 2Ω load

#8 .0605Ω 0.8% 1.5% 3.0%

#10 .1018Ω 1.3% 2.5% 5.1%

#12 .1619Ω 2.0% 4.0% 8.1%

#14 .2575Ω 3.2% 6.4% 12.9%

#16 .4094Ω 5.1% 10.2% 20.5%

#18 .6510Ω 8.1% 16.3% 32.6%

Table 4.1: Percentage of speaker load power lost in 100
foot run of 2-conductor cable.

4. CABLE REQUIREMENTS

4.1 Input Cables

Be sure to use shielded cable whether balanced
or unbalanced. Shielding which is properly grounded will
protect the signal from outside electrical interference such
as RF, fluorescent lighting, even computer noise. As a
general rule, unbalanced or single-ended (tip-sleeve) lines
of less than 10 feet are satisfactory, but greater distances
may require a balanced signal. Avoid running input lines
in close proximity or parallel to long speaker lines, AC
power cables, or power transformers, as this may gener­ate hum or oscillation.

4.2 Output Cables

The FTX Series III amplifiers are capable of de­livering high levels of output current, therefore the wire
gauge used for speaker cables is particularly important.
Inadequate wire gauge adds significant resistance to the
speaker’s own impedance, reducing the power which is
actually delivered to the speaker. It will also result in a
decrease in the damping factor and possible fire hazard.

5. RACK-MOUNTING REQUIREMENTS

5.1 Mechanical

All Ashly amps are designed to fit in standard
19-inch racks. The front panel rack-mount ears are suffi­ciently strong for most applications. If you desire further
integrity for mobile racks, we recommend using the four
additional holes in the back of the chassis for supplemen­tal rear-mounting (see dimensional drawings).

5.2 Cooling

If using an FTX amplifier, be certain that both
the front and back of the rack have unhindered access to
free air flow. Fan direction is from front to back. It is
not necessary to leave empty space above or below the
FTX amplifiers, however the CFT-1800 will cool more
efficiently with space above and below the chassis.

The following chart indicates max BTU per hour
for each amp under varying load conditions, so that ac­curate assessment of room ventilation needs can be made.
Thermal output is approximated by subtracting audio
output power from the total power consumption of the
amplifier. All values assume the amplifier is driving both
channels and just peaking at the clipping level.

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Operating Manual - FTX-1001, FTX-1501, FTX-2001, CFT-1800 Power Amplifier

t

AC Power

Off On

FTX-1001 FTX-1501 FTX-2001

Channel One

Channel Two

6. FRONT PANEL FEATURES

-

-

-1-18-21-24-27

-1-18-21-24-27

Outpu

Idle 210 BTU 250 BTU 620 BTU
8Ω loads 550 BTU 580 BTU 760 BTU
4Ω loads 800 BTU 970 BTU 1340 BTU
2Ω loads --- 2030 BTU 2590 BTU

Table 5.2: Max BTU per hour (both channels driven)

5.3 Grounding

In some installations where the sound system is
sensitive to RF noise or system-induced oscillation, it may
be necessary to ground the amplifier's chassis to the rack
enclosure. This is accomplished using star type
lockwashers on the four rack mounting screws. These
star washers will penetrate through the amplifier's paint
to adequately ground the chassis to the rack.

6

6.1 Power Switch

When the unit is switched on there is a 2 second
delay, during which time the PROTECT circuit will acti­vate. The load is disconnected during this power-up se­quence . When turning off the amplifier, the load is re­moved instantly, and the protect LED will briefly turn on
as the power supply discharges.

6.2 Thermal Status Meters

This left-most green LED, when turned on, indi­cates normal thermal status. If either amplifier channel
overheats, these lights will both turn off, indicating that
power has been cut off from the audio portion of the am­plifier. The AC Power Switch will remain lit, and the
cooling fan continues to operate until the amplifier is
within safe operating temperatures again.