Ashly TRA-4150 User manual

Multi-Channel Power Amplifiers
Operating Manual
Powerflex


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ASHLY AUDIO INC.
847 Holt Road Webster, NY 14580-9103 Phone: [phone]
Toll-Free: [phone] Fax: [phone]
www.ashly.com
Cha nnel 1 Cha nnel 2 Channel 3 Cha nnel 4
Protect
Thermal
Clip
Signal
Power
Powerflex
4400
Cha nnel 1 Cha nnel 2 Channel 3 Cha nnel 4 Channel 5 Cha nnel 6
Protect
Thermal
Clip
Signal
Power
Powerflex
6250

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Operating Manual - Powerflex Multi-Channel 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 & Earth Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 INDICATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7 REAR PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1 Input Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.2 Input Ground Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.3 Multi-Channel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.4 Input Level Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.5 Stereo/Mono Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.6 Dual Channel Mode/Bridge Mode Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.7 50Hz Low Cut Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.8 Loudspeaker Output Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.9 AC Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
8 SELF-PROTECTION FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1 Power Supply Undervoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.2 Power Supply Overvoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.3 Output Overcurrent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.4 Heat Sink Overtemperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.5 Unacceptable DC or High Frequency Output Content . . . . . . . . . . . . . . . . . . . . 10
8.6 AC Power Interruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9 TYPICAL APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1 Individual Channel Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.2 Dual Mono Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.3 Bridged Mono Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.4 Typical PA Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

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Operating Manual - Powerflex Multi-Channel Power Amplifier
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
The lightning flash with arrowhead symbol,
within an equalateral triangle, is intended to alert the
user to the presence of uninsulated "dangerous volt-
age" within the product's enclosure that may be of suf-
ficient magnitude to constitute a risk of electric shock
to persons.
The exclamation point within an equalateral tri-
angle is intended to alert the user to the presence of
important operating and maintenance instructions in
the literature accompanying the device.
TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER. NO USER SER-
VICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
TO REDUCE THE RISK OF FIRE OR ELECTRICAL SHOCK, DO NOT EXPOSE THIS
APPLIANCE TO RAIN OR MOISTURE.
TO REDUCE THE RISK OF FIRE, REPLACE ONLY WITH SAME TYPE FUSE.
REFER REPLACEMENT TO QUALIFIED SERVICE PERSONNEL.
WARNING: THIS APPARATUS MUST BE EARTHED THROUGH THE SUPPLIED
POWER LINE CORD
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.
10 DESIGN THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
11 TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1 No Audio Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.2 Distorted Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.3 Hum or Buzz Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
12 DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
13 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
14 WARRANTY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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Operating Manual - Powerflex Multi-Channel Power Amplifier
1. INTRODUCTION
TheAshly Powerflex amplifiers combine the effi-
ciency of a MOSFET high-speed switching output stages
with the sophistication of modern microprocessors and DSP
technology to produce a multi-channel amplifier with un-
precedented versatility and power in a single 3RU pack-
age.
Although similar to other amplifiers with class D
output stages, Powerflex amplifiers employ internal mi-
croprocessor and DSP algorithms to optimize output
switching characteristics and eliminate the usual harshness
associated with high-frequency audio in standard class D
amplifiers. This optimization results in a spread-spectrum
switched output that varies with input amplitude and fre-
quency, and minimizes radiated emissions by eliminating
the single-frequency high-energy radiated interference
normally associated with switching outputs. The use of a
simple linear power supply removes another potential
source of radio-frequency interference, an important con-
sideration as racks become more and more heavily popu-
lated with digital signal processing equipment. A small
switching supply using flyback topology provides an effi-
cient power source for logic, protection, pre-amplifier and
indicator circuits.
To assure reliable operation, the usual protection
from excessive high-frequency, DC offset, and thermal
overload is supplemented by power supply undervoltage,
power supply overvoltage, and output overcurrent detec-
tion, all monitored and controlled by the latest in minia-
turized microprocessor technology.
In sum, Ashly Powerflex amplifiers combine the
best of the new digital technologies with the best of the
traditional analog technologies to provide a product that
will supply clean sound at full output from every channel
while generating minimal heat, thus increasing the reli-
ability of every other piece of equipment in a rack as well
as preserving its own.
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 ship-
ping carton and all packing materials, as they were care-
fully designed to reduce to minimum the possibility of
transportation damage should the unit again require pack-
ing 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 avail-
able for inspection by the carrier. Save all packing mate-
rials until the claim has been settled.
3. AC POWER REQUIREMENTS
3.1 Voltage Requirements
The Powerflex amplifiers can be operated from
nominal 120VAC or 240VAC, 50/60Hz mains. This is user-
configurable by changing the insert in the AC Inlet (See
section 7.9). The power connector on the amplifier accepts
a standard IEC-320 receptacle.
For nominal 120VAC operation, the power cord
should be three-conductor, rated for at least 13A (16AWG).
The line fuse should be type MDA, 12A.
For nominal 240VAC operation, the power cord
should be three-conductor, rated for at least 10A (18AWG).
The line fuse should be type MDA, 10A.
3.2 Current Requirements
1.) Idle (no audio):
Powerflex 6250 Powerflex 4400
120V: 0.81A 120V: 0.9A
240V: 0.42A 240V: 0.5A
2.) With typical audio inputs:
8Ωloads on all channels
120V: 4A 120V: 4.6A
240V: 2A 240V: 2.3A
4Ωloads on all channels
120V: 6.5A 120V: 7.0A
240V: 3.3A 240V: 3.5A
70 Volt systems - (Powerflex 6250 Only,
3 channels Bridged Mono)
120V: 6.5A
240V: 3.3A
Powerflex amplifiers consumes less than 12 amps
when all channels operate at 1/8 power into rated (4 ohm)
loads. This condition satisfies the UL, CSA and building
electrical code requirements for a piece of audio equip-
ment not to consume more than 80% of the current avail-
able when plugged into a grounded 15 amp outlet and
operated at 1/8 of maximum power.

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Operating Manual - Powerflex Multi-Channel Power Amplifier
3.3 AC Grounding Requirements
To reduce the risk of ground loop hum, all system
ground references should originate at the same point in
yourAC power distribution. Do not remove the amplifier’s
ground pin, as it creates a potential shock hazard.
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, and computer/display emis-
sions. As a general rule, unbalanced or single-ended (tip-
sleeve) lines of less than 10 feet are satisfactory, but greater
distances or noisy field environments 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
Powerflex amplifiers are capable of delivering
high levels of output current, therefore the wire gauge used
for speaker cables is particularly important. Inadequate
wire gauge can add significant resistance to the speaker’s
own impedance, especially over long distances, reducing
the power which is actually delivered to the speaker. It
could also result in a decreased damping factor and pos-
sible fire hazard. Since power at the speaker load is of
primary concern in system design, we have included a table
to best determine appropriate wire gauge for your appli-
cation. The following table lists the resistance per 100
feet of common copper wire gauges, and also gives the
percentage of the speaker load power which would be lost
in an arbitrary 100 ft run of different gauges of 2-conduc-
tor copper speaker wire.
Wire Gauge Ω/100ft 8Ωload 4Ωload
#8 .0605Ω0.8% 1.5%
#10 .1018Ω1.3% 2.5%
#12 .1619Ω2.0% 4.0%
#14 .2575Ω3.2% 6.4%
#16 .4094Ω5.1% 10.2%
#18 .6510Ω8.1% 16.3%
Table 4.1: Wire gauge resistance/power loss
This table expresses the power loss as a percent-
age of the load’s power rather than the total amplifier out-
put power in order to accurately determine power loss at
other cable lengths. For example, if you plan to deliver
150 watts to an 8Ωload through 50 ft of 14 ga. cable, the
power loss in the cable would be half that of a 100 ft run
of #14 wire as shown in the table, or 1.6% of 150W, which
is an insignificant 2.4 watts. However, if you were to run
200 ft of 18 ga. cable to a 4Ωload, the loss would be twice
that of the 100 ft run shown in the table, or 32.6% of 250W,
which is 81.5 watts lost as heat. Always be sure to use
adequate gauge speaker wire.
5. RACK-MOUNTING REQUIREMENTS
5.1 Mechanical
Powerflex amplifiers are designed to fit in stan-
dard 19-inch equipment racks. The front panel rack-mount
ears are sufficiently strong for most applications,however
if you desire further integrity for mobile racks, we recom-
mend using the four additional holes in the back of the
chassis for supplemental rear-mounting (see dimensional
drawing for details).
5.2 Cooling
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.
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 ad-
equately ground the chassis to the rack.

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Operating Manual - Powerflex Multi-Channel Power Amplifier
6. FRONT PANEL INDICATORS
6.1 Power Switch
When the unit is switched on there is a five sec-
ond delay, during which time the PROTECT circuit will
activate, disconnecting the speakers from the amplifier
output. 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 Signal Indicator
The signal present LEDs illuminate at an input
level of about 13mVrms (-35.5dBu).
6.3 Clipping Indicator
The clipping LEDs illuminate at an input level of
about 870mVrms (+1.0dBu), with all channels driven by
1KHz into 8Ω. This indicates that the signal processing
circuitry has determined output levels to be approaching
the available power supply rails and has begun to “soften”
signal peaks. Actual onset of “hard” clipping depends on
audio program and total load impedance and does not oc-
cur until the signal processing circuitry can no longer com-
pensate, which means that signal integrity can be
maintained even if the clipping indicators illuminate for
short periods of time.
6.4 Thermal Status Indicator
The thermal LEDs illuminate when the tempera-
ture of any one of the heat sink extrusions reaches 85 to
90°C. Both channels of the affected amplifier module will
shut off until the measured temperature drops below about
70°C. The amplifier should be able to maintain proper
operation at an ambient room temperature of 50°C (122°F)
or less with typical audio program and all channels driven
into 4Ω.
6.5 Protect Indicator
The protect LEDs illuminate when the fault moni-
toring microprocessor has determined that one of the fol-
lowing conditions exists:
- Power supply undervoltage
- Power supply overvoltage
- Output overcurrent
- Heat sink overtemperature
- Unacceptable DC output content
- Unacceptable high frequency output content
- AC power interruption
Because the signal processing module used in
Powerflex amplifiers processes two channels simulta-
neously, a fault in one channel will result in a protect con-
dition for both channels processed by the same module,
ex. channels 1-2, 3-4, and 5-6 (6250 only). Thus there
will never be a case where only one of the amplifier chan-
nels is shown in protect mode. When a pair of protect
LED's are illuminated, internal relays have removed the
channel pair's speaker loads from the amplifier output and
connected the speakers to ground. If the fault is isolated
to one module (channel pair), the other channels will re-
main unaffected.
Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel 6
Protect
Thermal
Clip
Signal
Power
Powerflex
6250
0

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Operating Manual - Powerflex Multi-Channel Power Amplifier
7. REAR PANEL FEATURES
7.1 Input Connectors
The Powerflex inputs use 1/4" tip-ring-sleeve (TRS) phone jacks, balanced XLR jacks, and balanced two piece
"Euroblock" style connectors. The three types of connectors are wired in parallel and may be used balanced or unbal-
anced. Use the euro-block connectors to daisy-chain multiple amps together . Input XLR jacks are pin 2 hot (+),
meaning that a positive voltage applied to pin 2 will result in a positive output voltage across the speaker terminals. Pin
2 of the XLR jack is equivalent to the tip of the 1/4"TRS jack.
Balanced Inputs
It is recommended that balanced input connections
be used whenever possible to take full advantage of the
amplifier's common mode rejection properties, and to reduce
ground-loop problems. The (+) signal is on pin 2 of the XLR,
and the tip of the phone jack. The (-) signal is on pin 3 of the
XLR, and the ring of the phone jack. If a hum problem per-
sists, try connecting a balanced signal to the Euroblock input
with the input cable's shield lifted at the amplifier end of the
cable (ie. no ground connection), but connected to ground at
the signal source. This eliminates potential ground currents
through the input cable yet preserves the benefits of shield-
ing.
Unbalanced Inputs
If an unbalanced XLR input connection is used, pin 3
should be connected to input ground (pin 1). If the 1/4" input
jack is used unbalanced, the use of a mono (tip-sleeve) plug
will automatically tie the (-) connection to input ground. Note:
Never float the (+) or (-) input connection when using an un-
balanced source. If connecting an unbalanced signal to the
Euroblock input, connect the signal to (+) and the cable shield
to both (-) and ground.
Mono Phone Plug
Unbalanced Connection
Tip (+)
Sleeve (Ground)
2=(+)
3=(gnd)
1=(gnd)
LR Male
Unbalanced
Connection
Euroblock
Input Connector
-+
Ground
+-
Signal (+)
(-) Input
Tied To
Ground
Unbalanced Audio Connections
Tip (+)
Ring (-)
Sleeve (Ground)
Stereo Phone Plug
Balanced Connection
LR Male
Balanced
Connection
2=(+)
3=(-)
1=(gnd)
Euroblock
Input Connector
-+
Ground
+-
Balanced Audio Connections
0
* Powerflex 6250 shown - Powerflex 4400
only has channels 1-4.

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Operating Manual - Powerflex Multi-Channel Power Amplifier
7.2 Input Ground Switch
This switch separates internal circuit ground from
the chassis ground on all inputs. Ground connections from
an incoming signal are always connected to internal cir-
cuit ground, but float from the chassis ground as long as
the switch is out. Unless there are special circumstances
which require the circuit ground and chassis ground to be
connected, it is best to leave this switch out.
7.3 Multi-Channel Operation
The Powerflex 6250 is essentially three stereo
amplifiers in one chassis, for a total of up to six separate
channels. Similarly, the Powerflex 4400 is essentially two
stereo amplifiers in one chassis, for a total of up to four
separate channels. Thus, the following references to Ste-
reo, Mono, or Bridged operation is with regard to each
pair of channels in the amplifier. For example, Channel 1
and Channel 2 together can provide stereo, mono, or
bridged operation, completely independent of Channels 3-
4 or Channels 5-6 settings (6250 only).
7.4 50Hz Low Cut Switch
Each pair of channels has a 50Hz second order
(12 dB per octave) low-cut filter option which is applied
to both channels within the pair. When the switch is
pressed, the audio signal is -3dB at 50Hz, -15dB at 25 Hz,
-27dB at 12.5Hz, etc.
7.5 Input Level Controls
Input Level Controls attenuate input signal from
0dB down to -∞. For best performance,Ashly recommends
that the level controls be operated at full level (0 dB at-
tenuation).
In STEREO mode, each level control corresponds
directly to the input signal on its respective channel.
In MONO Mode, the input signal connected to
channels 1, 3, or 5 are used to drive channels 2, 4, or 6
respectively, and the level controls for channels 1, 3, and
5 likewise control channels 2, 4, and 6. When switched to
Mono mode, channels 2, 4, or 6 level controls become in-
active. In BRIDGED mode, the level controls function
the same as in mono mode.
7.6 Stereo/Mono Switch
Powerflex amplifiers are comprised of two (4400)
or three (6250) stereo amplifiers, each operating indepen-
dently of the others, with Stereo/Mono switching avail-
able for each channel pair. If this switch is set to Stereo
mode, the channel pair operates as two discrete amplifi-
ers, each with its own input connection and level control.
Switching to Mono mode allows one input (chan-
nel 1, 3, or 5) to drive both channels of a stereo channel
pair. Pressing the Mono switch disables the channel pair's
other input connection, as well as its level control. The
first channel's input and level control now determines the
signal to both channels.
7.7 Dual Channel/Bridge Mode Switch
Bridging a power amplifier is the process whereby
two channels are supplied the same signal, with the sec-
ond channel's phase inverted 180°. The speaker is then
connected across the (+) output connections of each chan-
nel, resulting in twice the power to the speaker that either
channel could deliver by itself. Since in Bridge Mode both
connections have voltage present, never connect or touch
either speaker wire to ground. In the Powerflex 6250, use
Bridge mode for 70V applications as well.
115V
115V or 230V
50-60Hz
1400W
AC
Replace Only With
Same Type Fuse.
Refer To Owner's Manual
For Proper Fuse Rating.
Ch 1 In
(Mono)
Ch 2 In Ch 3 In
(Mono)
Ch 4 In Ch 5 In
(Mono)
Ch 6 In
Ch2Ch1 Ch4 Ch6
Input
1
2
3
56
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mono
Stereo
Bridge
Dual
LoCut
Norm
Ch.
1-2
(1-2 M ono)
Ch1
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Bridge
Dual
LoCut
Norm
50Hz
1
2
37
8
9
0
4
10
1
2
3
6
7
8
9
010
Bridge
Dual
LoCut
Norm
50Hz
Ch2 (3-4 Mono) Ch3 Ch4 (5-6 Mono) Ch5 Ch6
Chassis
Float
Ground
Ch.
3-4
Ch.
5-6
(-)(+)
2
3
1
555 6 5 5
Mono
Stereo
Mono
Stereo
-+
Ground +--+ Ground +--+ Ground +-
(Mono) Ch3(Mono) Ch5(Mono)
PUSH
PUSHPUSHPUSHPUSHPUSH
*
Powerflex
6250 shown -
Powerflex
4400 only has
inputs 1-4.

9
Operating Manual - Powerflex Multi-Channel Power Amplifier
The Powerflex 6250 is capable of three channels
of bridged output, while the Powerflex 440 is capable of
two channels of bridged output. To use bridged mode,
first press MONO from the Stereo/Mono switch on the
channel pair to be bridged. This sends the same audio
signal to both channels. Then press BRIDGE from the
Dual/Bridge switch on the channel pair to be bridged. This
inverts the phase of the input signal to the second channel.
These two channels are now operating together in Bridged
Mono mode, and the output must be taken from the two
red binding posts corresponding to the bridged channel
pair Observe polarity by noting which red binding post is
(+) and which is (-)
7.8 Speaker Outputs - Binding Posts
Dual binding posts provide connections for the
speaker outputs. In addition to using the banana-type plug,
the binding posts have a slotted entry-way for wire-crimped
spade terminals. In BRIDGE/70V mode, the channel 1, 3,
or 5 red binding post is the (+) in-phase speaker output
terminal and the channel 2, 4, or 6 red binding post be-
comes the (-) out-of-phase speaker terminal.
CAUTION! NEVER CONNECT THETWO RED
BINDING POSTS TOGETHER OR CONNECT EITHER
RED BINDING POST TO A BLACK BINDING POST!
7.9 AC Inlet
Powerflex amplifiers can be configured by the cus-
tomer for operation at either 115VAC or 230VAC mains.
Switching from one to the other simply requires the fol-
lowing steps:
1.) Unplug the amplifier from the wall and re-
move the power cord from the rear of the amplifier.
2.) Using a small screwdriver as a lever, unlatch
the fuse holder in the AC inlet and remove it.
3.) Remove the voltage selection insert and ro-
tate until the new nominal mains voltage level indication
(115 or 230) is on top and properly oriented for reading.
4.) Replace the voltage selection insert in theAC
inlet, making sure that it is plugged in all the way.
5.) Replace the fuse with the appropriate size (see
#6 below), and press the fuseholder back into the AC inlet
until it latches.
6.) Using a power cord of the appropriate size
and with the appropriate terminations, plug the cord into
the rear of the amplifier and then into the wall. The
Powerflex amplifier is now ready for use at the new mains
voltage. If the mains voltage is 110-125VAC, the required
fuse is MDA 12, 250V, and the required power cord is 3-
wire grounded, 13 Amp (16AWG) minimum.
If the mains voltage is 220-250VAC, the required
fuse is MDA 10, 250V, and the required power cord is 3-
wire grounded, 10 Amp (18AWG) minimum.
+-
Bridge/70V
Ch1
(+)
(-)
Ch2
(+)
(-)
+-
Bridge/70V
Ch3
(+)
(-)
Ch4
(+)
(-)
+-
Bridge/70V
Ch5
(+)
(-)
Ch6
(+)
(-)
OUTPUTS
Ashly Au io Inc.
Ma e In USA
Powerflex 6250
150W/Chan - 8
Ω
BRIDGE MODE: Take Output
From Two Re Posts.
Do Not Connect Either Output
Wire To Groun .
Dual Stereo/Dual Mono Mode:
Bridged Mono Mode:
250W/Chan - 4
Ω
500W Bri ge - 8
Ω
*
Powerflex
6250 shown -
Powerflex
4400 only has
channels 1-4
with no 70V
output.

10
Operating Manual - Powerflex Multi-Channel Power Amplifier
8. SELF-PROTECTION FEATURES
Powerflex amplifiers contain circuitry to self-pro-
tect during extreme fault conditions. These fault condi-
tions are:
1.) Power supply undervoltage
2.) Power supply overvoltage
3.) Output overcurrent
4.) Heat sink overtemperature
5.) Unacceptable DC or high frequency output content
6.) AC power interruption
Except for AC power interruption, the detection
of any fault will result in the activation of protection cir-
cuitry on a particular module, which consists of two chan-
nels. That is, a short circuit on the output of channel 1
will result in both channel 1 and channel 2 entering pro-
tect mode. This is because the signal processing module,
which processes both channels simultaneously, does not
distinguish between the two channels within a channel pair
when processing a fault.
An AC power interruption will result in all chan-
nels entering protect mode simultaneously, just as if the
amplifier is being turned off.
In all cases, the amplifier will restart the signal
processing module after a short delay and will reconnect
the speakers after several seconds if no further fault con-
ditions exist. This allows the servo circuitry to bring any
residual DC offsets to zero before speakers are connected.
Specific conditions resulting in a fault are as follows:
8.1 Power supply undervoltage - less than about
55 volts on the either supply rail. Possible causes would
be total load on the outputs exceeding recommendations
(remove some speakers - 4Ωload min, 8Ωmin bridged),
low AC mains voltage (reduce extension cord length or
increase wire size, or switch to an AC mains circuit more
capable of supporting the amplifier's power requirements),
or improper AC inlet mains voltage setting (make sure
nominalAC mains voltage matches the number in the view-
ing window on the AC inlet).
8.2 Power supply overvoltage - more than about
92 volts on either supply rail. Possible causes would be
highAC mains voltage (change to anAC mains circuit with
voltage within the amplifier's stated requirements) or im-
properAC inlet mains voltage setting (make sure nominal
AC mains voltage matches the number in the viewing win-
dow on the AC inlet).
8.3 Output overcurrent - more than 15 to 20 amps
being drawn from any output. Possible causes would be
total load on the affected output exceeding recommenda-
tions (disconnect some speakers), or a short circuit on one
of the outputs driven by the affected module (inspect
speaker wiring for proper connection).
The above conditions are checked by the signal
processing module on a switching cycle by switching cycle
basis and are therefore monitored as often as a million or
more times a second, allowing protection well before de-
structive conditions have time to cause part failure.
8.4 Heat sink overtemperature - a measured heat
sink extrusion temperature of more than 85 to 90 degrees
C. The three-speed fan will switch to medium speed at an
extrusion temperature of 45 to 50 degrees C, and to high
speed at a temperature of 70 to 75 degrees C. The
overtemperature fault will clear itself when the measured
temperature is below about 70 degrees C. The fan will
operate at low speed below about 50 degrees C.
8.5 Unacceptable DC or high frequency output
content - a DC offset in the output signal of more than a
few hundred millivolts indicates module failure, and will
trigger a DC protect fault. High frequency (20kHz to
100kHz) in the output at high amplitudes can cause speaker
damage and causes a fault condition more or less rapidly
as frequency and amplitude vary.
These two conditions (DC and HF) are tested by
the same circuit so the exact cause cannot be isolated. If
the fault condition persists after disconnecting all inputs
and outputs from the amplifier, there is probably a module
failure requiring service. Note: the self-testing circuit may
take as long as 30 seconds to recover from this fault, so be
sure to give the amplifier enough time to reset itself. If
after 30 seconds the module has recovered, begin plug-
ging in one input and output at a time in an effort to iso-
late a system high-frequency or oscillation problem.
8.6 AC power interruption - a dropout (or brown-
out of sufficient magnitude) of more than one half mains
line cycle and less than one whole cycle in duration.

11
Operating Manual - Powerflex Multi-Channel Power Amplifier
9. TYPICALAPPLICATIONS
The Powerflex 6250 is essentially three stereo amplifiers in one chassis, each with dual stereo, dual mono, and
bridged mono capabilities, while the Powerflex 4400 is two stereo amplifiers (four channels), but with more power per
channel than the 6250. The ability to easily mix and match various configurations is what puts the "flexibility" in
Powerflex. Input connections can be 1/4" phone plug, XLR, or hard-wired with two-piece Euroblock connectors, while
speaker outputs can be either "banana" type plugs or wire crimped spade terminals. Note: The Powerflex 6250 is used
for the following application details, but the 4400 is used in a similar fashion, to a maximum of four channels.
9.1 Individual Channel Setup
+-
Bridge/70V
Ch1
(+)
(-)
Ch2
(+)
(-)
+-
Bridge/70V
Ch3
(+)
(-)
Ch4
(+)
(-)
+-
Bridge/70V
Ch5
(+)
(-)
Ch6
(+)
(-)
OUTPUTS
Ashly Au io Inc.
Ma e In USA
Power flex 62 50
-+
Gro u n +-
Ch 1 In Ch 2 In
-+
Gro u n +-
Ch 3 In Ch 4 In
-+
Gro u n +-
Ch 5 In Ch 6 In
Ch2Ch1 Ch3 Ch4 Ch5 Ch6
Input
1
2
3
56
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
Ch.
1-2
(1-2 Mono)
Ch1
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
50Hz
Ch2 (3-4 Mono) Ch3 Ch4 (5-6 Mono) Ch5 Ch6
Chassis
Float
Ground
Ch.
3-4
Ch.
5- 6
5 5 5 5 5
 " $
Input Section:
Up to Six Different Inputs
Stereo/Mono Switches - Out
Dual Bridge Switches - Out
Levels Controls - Used Per Input Channel
Speaker Outputs - Up To Six Different Outputs
Minimum Speaker Load Per Channel = 4
Ω
 ! " # $
Up To Six Different Amplifier Inputs
Six Channel Setup (dual stereo)
Multi-Media Systems
Surround Sound
Three Way Biamplification
Stereo Triamplification
Possible Applications:
Multiple Zone Systems
Three Pairs Of Studio Monitors
Multiple Stage Monitors
25V Distributed Systems (6250 Only)
(Mono)
(Mono) (Mono) (Mono)
(Mono) (Mono)
! #
9.2 Dual Mono Setup
+-
Bridge/70V
Ch1
(+)
(-)
Ch2
(+)
(-)
+-
Bridge/70V
Ch3
(+)
(-)
Ch4
(+)
(-)
+-
Bridge/70V
Ch5
(+)
(-)
Ch6
(+)
(-)
OUTPUTS
Ashly Au io Inc.
Ma e In USA
Powerflex 6250
-+
Gro u n +-
Ch 1 In Ch 2 In
-+
Gro u n +-
Ch 3 In Ch 4 In
-+
Gro u n +-
Ch 5 In Ch 6 In
Ch2Ch1 Ch3 Ch4 Ch5 Ch6
Input
1
2
3
56
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
Ch.
1-2
(1 -2 Mono)
Ch1
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
50Hz
Ch2 (3 -4 Mono) Ch3 Ch4 (5-6 Mono) Ch5 Ch6
C h assi s
Float
Ground
Ch.
3-4
Ch.
5- 6
5 5 5 5 5
 ! #
Input Section:
Up to Three Different Inputs
Stereo/Mono Switches - In
Dual Bridge Switches - Out
Levels Controls - Only Channels 1, 3, or 5 Used
Minimum Speaker Load Per Channel = 4
Ω
 ! " # $
Amplifier Inputs
(An Input Can Be Parallel Connected
To Other "Non-Partner" Channels by
H
ard-Wire Jumping the Euroblock Connectors)
Du al Mono Setup
Possible Applications:
Multiple Zone Systems
Three Different Stage Monitor Mixes
Dual-Mono FOH Tri-Amplification
Channels 1 & 2
From Channel 1 Input Channels 3 & 4 From Channel 3 Input Channels 5 & 6 From Channel 5 Input
(Mono)
(Mono) (Mono) (Mono)
(Mono) (Mono)

12
Operating Manual - Powerflex Multi-Channel Power Amplifier
9.3 Bridged Mono Setup
9.4 Typical PA Setup
(Mono) (Mono)
+-
Bridge/70V
Ch1
(+ )
(-)
Ch2
(+ )
(-)
+-
Bridge/70V
Ch3
(+ )
(-)
Ch4
(+ )
(-)
+-
Bridge/70V
Ch5
(+ )
(-)
Ch6
(+ )
(-)
OUTPUTS
Ashly Au io Inc.
Ma e In USA
Power flex 6250
-+
Gro u n +-
Ch 1 In Ch 2 In
-+
Gro u n +-
Ch 3 In Ch 4 In
-+
Gro u n +-
Ch 5 In Ch 6 In
Ch2Ch1 Ch3 Ch4 Ch5 Ch6
Input
1
2
3
56
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mono
Stereo
Bridge
Dual
Lo C u t
No r m
Ch.
1-2
(1 -2 Mono)
Ch1
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mono
Stereo
Bridge
Dual
Lo C u t
No r m
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mono
Stereo
Bridge
Dual
Lo C u t
No r m
50Hz
Ch2 (3 -4 Mono) Ch3 Ch4 (5-6 Mono) Ch5 Ch6
Chassis
Float
Ground
Ch.
3-4
Ch.
5- 6
5 5 5 5 5

Input Section:
Up to Three Different Inputs
Stereo/Mono Switches - In
Dual/Bridge Switches - In
Levels Controls - Only Channels 1, 3, or 5 Used
Minimum Speaker Load Per Bridged Channel Pair = 8
Ω
Amplifier Inputs
Bridged Mono Setup
Possible Applications:
70 Volt Constant Voltage Systems (6250 Only)
Subwoofers
High Powered Monitors
High Powered Full Range PA Speakers
Bridged Channels 1 & 2
From Channel 1 Input Bridged Channels 3 & 4 From Channel 3 Input Bridged Channels 5 & 6 From Channel 5 Input
(+ ) (- ) (+ ) (- ) (+ ) (- )
(Mono)
(Mono) (Mono) (Mono)
(Mono) (Mono)
! #
+-
Bridge/70V
Ch1
(+)
(-)
Ch2
(+)
(-)
+-
Bridge/70V
Ch3
(+)
(-)
Ch4
(+)
(-)
+-
Bridge/70V
Ch5
(+)
(-)
Ch6
(+)
(-)
OUTPUTS
Ashly Au io Inc.
Ma e In USA
Power flex 62 50
-+
Gro u n +-
Ch 1 In Ch 2 In
-+
Gro u n +-
Ch 3 In Ch 4 In
-+
Gro u n +-
Ch 5 In Ch 6 In
Ch2Ch1 Ch3 Ch4 Ch5 Ch6
Input
1
2
3
56
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
Ch.
1-2
(1-2 Mono)
Ch1
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
50Hz
1
2
3
6
7
8
9
0
4
10
1
2
3
6
7
8
9
010
Mo n o
Stereo
Bridge
Dual
Lo C ut
No r m
50Hz
Ch2 (3-4 Mono) Ch3 Ch4 (5-6 Mono) Ch5 Ch6
Chassis
Float
Ground
Ch.
3-4
Ch.
5- 6
5 5 5 5 5
 ! # $
Subwoofer
Input
(Bridged Mono)
Full Range
Input
(Dual Mono)
Monitor
Inputs
(Dual Stereo) Subwoofer
Bridged Output
8
Ω
Minimum
Dual Full Range
Outputs
4
Ω
Min/Channel
Separate Monitor
Outputs
4
Ω
Min/Channel
(Mono)
(Mono) (Mono) (Mono)
(Mono) (Mono)

13
Operating Manual - Powerflex Multi-Channel Power Amplifier
10. DESIGN THEORY
Powerflex amplifiers are based on stereo driver
modules that use digital processing to generate a spread-
spectrum switching pattern between about 200KHz and
1.5MHz, depending on input signal amplitude and fre-
quency. This overcomes the self-limiting and inherent
weakness in traditional class D fixed-frequency PWM
amplifiers, and produces an output with THD+N numbers
comparable to classA and classAB linear amplifiers. (see
Specification Notes at end of this section)
In Powerflex amplifiers, the input signal is re-
ceived by a single operational amplifier configured as a
difference amplifier to reduce common-mode effects from
sources located at a distance. This difference amplifier has
a gain of 2.74 which allows the use of less gain later in the
system, improving overall system noise performance.
The amplified signal, based on the position of
various selector switches, either bypasses or is processed
by a two-pole high-pass filter with rolloff at 50Hz, and
then passes through the attenuating potentiometer. The
attenuated signal is buffered and passed to the amplifier
module along with a zero-volt reference.
The amplifier module receives the attenuated sig-
nal with a unity gain differential amplifier to eliminate
common-mode interference picked up within the ampli-
fier chassis. The signal is then added to a small DC offset
signal opposite in polarity to any DC offset on the
Powerflex output bridge and adjusted by the digital pro-
cessing module as described above. The digital process-
ing module, which also generates FET drive signals, has a
voltage gain of 11.7 for a total system voltage gain of 32.
The drive signals generated by the processing module are
fed to a pair of high-current MOSFET transistors, and the
switched output of these transistors is filtered and applied
to the speaker outputs. Fault conditions such as overvolt-
age, undervoltage, and output overcurrent are measured
by the module and therefore affect a stereo pair of chan-
nels regardless of whether the fault actually exists on both
channels processed in the module. Since every action ap-
plied to protect the digital processing module affects both
channels being processed, other fault conditions are not
separated by channel, but rather by amplifier module.
Specification Notes:Due to its spread spectrum out-
put switching pattern, the output signal of a Powerflex ampli-
fier contains significant dynamic frequency content* far outside
the audio band, which makes no difference to audible perfor-
mance, but which makes heavily bandwidth-limited** measure-
ment of amplifier noise and distortion characteristics mandatory.
*variable 200KHz to 1.5MHz
**greater than 48dB/octave above 22kHz
11. TROUBLESHOOTINGTIPS
11.1 No Audio Output
1.) Power LED not lit:
Line fuse is blown or power outlet is dead.
IF LINE FUSE IS BLOWN, REPLACE ONLY
WITH SAME TYPE AND RATING FUSE.
2.) Power LED is lit but Protect LEDs stay on:
Amp module is in protect mode. Speakers have
been disconnected from amplifier output and connected to
ground until the protect fault is corrected. See section 8
for a complete explanation of protect fault conditions. Out-
put overcurrent, overvoltage and undervoltage faults will
reset in about eight seconds once the fault condition is re-
moved, while excessive DC offset or high frequency faults
take about 30 seconds to reset.
Speaker Impedance: The Powerflex amplifier
may go into self-protect at high output levels if the actual
speaker load impedance is much less than 4 ohms. To cal-
culate speaker impedance for a given combination of di-
rect-coupled speakers, use Ohm's law as applied to series
and/or parallel resistor networks, where each speaker (for
this purpose) can be thought of as a single resistor, using
DC resistance measurements.
Simply stated, speakers connected in series will add
together their impedance. Conversely, two speakers con-
nected in parallel will result in half the impedance, three
parallel speakers a third the impedance, four speakers a
fourth, and so on, assuming the speaker impedances are all
the same. Don't use mismatched impedances in parallel.
When using paralleled speakers, the available amplifier
power for that channel is evenly divided among speakers,
so 100 watts driving two parallel speakers of equal imped-
ance provides 50 watts to each speaker, etc. Combining
series/parallel speaker connections is common practice, but
if not sure, contact your dealer or Ashly tech support.
3.) Thermal LED and Protect LEDs stay on:
Amp module is in thermal protect mode and needs
to cool. The fan will continue to run while in thermal pro-
tect, and other modules will continue to function. See sec-
tion 8.4 for details.
4.) Power LED lit but no Signal LED activity
There is no input signal applied or input level con-
trols are turned down.

14
Operating Manual - Powerflex Multi-Channel Power Amplifier
11.2 Distorted Sound
1.) Clip LED is flashing regularly
Amplifier is being overdriven. Turn down the in-
put level control, or reduce the output level from the sig-
nal source.
2.) Clip LED is not flashing at all
Amplifier input signal may be exceeding input
headroom, which is greater than +12dBu, or 3.4V rms
(measured using continuous 1kHz sine wave). Incoming
signal level higher than +12.8 dBu will cause distortion in
the amplifier. Turning down the input level controls will
not eliminate distortion if the input headroom is exceeded.
Turn down the output level of the device driving the am-
plifier instead.
Additionally, an input signal may already be dis-
torted before it gets to the amp. Check to see if a piece of
equipment in the signal chain before the amp is clipping.
For best performance, the amplifier should be operated with
input levels fully CW. Also check for damaged speaker
drivers that could cause distorted sound.
12. POWERFLEX DIMENSIONS
Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel 6
Pr ot ect
Thermal
Cl i p
Signal
Po wer
Powerflex
6250
16.94"
13.54"
5.19"
4.75"
2.25"
18.5"
19"
2.25"
13.18"
1.25"
11.3 Hum or Buzz Noise
Be sure that the power cord’s 3-prong plug is con-
nected to a properly earth-grounded outlet. Lifting the
grounding third prong may not improve hum or buzz and
can create a potential shock hazard.
Hum is usually caused by ground currents flow-
ing between different pieces of equipment. Ground cur-
rents can be minimized by using a single point AC ground
for the sound system, and by using balanced connections
with quality cable throughout the audio path.
Buzz, as well as certain audible high frequency
tones, can be caused by environmental emissions such as
lighting dimmers, neon lights, or computer equipment. Use
balanced connections, and try moving the amplifier, wir-
ing, lighting, or other equipment to different locations to
isolate the source of the noise.
Sections 3.3, 5.3, 7.1, and 7.2 further discuss is-
sues related to grounding and noise problems.

15
Operating Manual - Powerflex Multi-Channel Power Amplifier
Typical Idle CurrentPowerflex 6250 Powerflex 4400
120V: 0.81A 120V: 0.9A
240V: 0.42A 240V: 0.5A
Current with TypicalAudio Program Material (4 ohm load
- all Channels) Powerflex 6250 Powerflex 4400
120V: 6.5A 120V: 7.0A
240V: 3.3A 240V: 3.5A
Connections
Input: XLR - 1/4” (Pin 2: Hot, Tip: Hot), Euroblock
Output: 5-Way Binding Post
Cooling: ForcedAir,Thermal Sensitive 3-Speed Fan, Front
Inlet/Rear Outlet
Dimensions: 19”L x 5.25”H x 16.5”D
Construction:All-Steel Chassis,ExtrudedAluminum Front
Panel
Weight: 45lbs
Specification conditions: 120VAC mains at 60Hz, 25° C
* Continuous power limited by power line capacity
**Non-conventional amplifiers require bandwidth limiting
for all distortion and noise measurements.
†Signal peaks in audio programming may trigger protec-
tion circuitry at low line voltages. Specifications are subject to
change or improvement without notice.
14. WARRANTY INFORMATION
We thank you for your expression of confidence
in Ashly products. The unit you have just purchased is
protected by a limited five year warranty. To establish the
warranty, you must first complete and mail the warranty
card attached to your product.
Fill out the information below for your records.
Serial Number _________________________________
Dealer ______________________________________
Date of Purchase _______________________________
Dealer’s Address _______________________________
______________________________________
Dealer’s Phone ________________________________
Salesperson ___________________________________
13. SPECIFICATIONS
*Power Output
(Maximum Average Power, 0.1% THD, 1KHz)
Rated Per Channel, Two Channels Driven
Powerflex 6250 Powerflex 4400
4 ohm: 250 Watts RMS 400 Watts RMS
8 ohm: 150 Watts RMS 275 Watts RMS
25V (6250 only) 150 Watts RMS *
Mono Bridged (1 Channel)
8 ohm: 500 Watts RMS 800Watts RMS
70V (6250 only) 500 Watts RMS *
Rated Per Channel, All Channels Driven
Powerflex 6250 Powerflex 4400
4 ohm: 250 Watts RMS† 400 Watts RMS†
8 ohm: 150 Watts RMS 275 Watts RMS
25V (6250 only) 150 Watts RMS *
Mono Bridged (3 channels)
8 ohm: 500 Watts RMS 800Watts RMS
70V (6250 only) 500 Watts RMS *
Input Impedance: 10K ohm balanced, 37K ohm unbal-
anced
High Pass Filter: 50Hz, 12dB/octave
**Total Harmonic Distortion (20Hz - 20KHz @ 8 ohms):
<0.2%
**IMD
(SMPTE 60Hz/7KHz 4:1)
@ 8 ohms: <0.2% (throughout power range)
(IHF) @ 8 ohms: <0.1% (throughout power range)
**Hum and Noise: -100dB from full output (A-weighted)
Full Power Input Sensitivity:
Powerflex 6250 Powerflex 4400
1.05V RMS (2.6dBu) 1.25V RMS (4.15dBu)
Frequency Response:
8 ohm: ±0.5dB 20Hz-20kHz
4 ohm: ±1.5dB 20Hz-20kHz
Voltage Gain: 32X (30.1dB)
Crosstalk: < -80dB (20Hz - 1KHz)
Signal Present Signal Sensitivity: 13mV RMS (-35.5dBu)
Power Requirement: 110-125VAC, 220 - 250VAC
50/60Hz

Operating Manual - Powerflex Multi-Channel Power Amplifier
Printed in USA 10/01 6250-3
ASHLY AUDIO INC. 847 Holt Road Webster, NY 14580-9103
Phone: [phone] Fax: [phone]
Toll Free [phone]
www.ashly.com
 2001 by Ashly Audio Corporation. All rights reserved worldwide.