Ashly MFA-8000, MFA-6000 User Manual
MFA-8000
MFA-6000
Power Amplifier
Operating Manual
Channel One Output Level
AC Power
Off On
Thrm
Protect
0(Clip)-3-6-9-12-15-18-21-24-27-3 0
Limit
Dual Monaural Amplifier
Channel Two Output Level
Thrm
Protect
MFA-6000
0(Clip)-3-6-9-12-15-18-21-2 4-2 7-30
Limit
Dual Monaural Amplifier
Channel One Output Level
AC Power
Off On
Thrm
Protect
0(Clip)-3-6-9-12-15-18-21-24-27-3 0
Limit
Channel Two Output Level
Thrm
Protect
MFA-8000
0(Clip)-3-6-9-12-15-18-21-2 4-2 7-30
Limit
ASHLY AUDIO INC.
847 Holt Road Webster, NY 14580-9103 Phone: (716) 872-0010
Toll-Free: (800) 828-6308 Fax: (716) 872-0739 Inter net: http://www.ashly.com/
Operating Manual - MFA-8000 and MFA-6000 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
6 FRONT PANEL FEATURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1 Power Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.2 Output Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.3 Clipping Indicator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.4 Limit Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.5 Thermal Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.6 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
7.6 Speaker Outputs - Speakon Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8 INPUT OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1 Input Isolation Transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.2 Peak Limiter Compressor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.3 Two-Way Crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.4 Mic-Line Mixer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
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Operating Manual - MFA-8000 and MFA-6000 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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.
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Operating Manual - MFA-8000 and MFA-6000 Power Amplifier
1. INTRODUCTION
The MFA Series amplifiers achieve the very high
energy levels used in today’s professional sound systems,
carefully maintaining control and accuracy while delivering high power to modern loudspeaker configurations.
The MFA 8000 (MFA 6000) will deliver 1200 Watts
(800W) per channel into 4Ω, and up to 3000 Watts
(1800W) bridged-mono into 4Ω. They are Ashly Audio’s
highest-powered amplifiers, employing an advanced
power supply circuit capable of delivering continuous high
current to the most demanding loads. The MFA amplifiers have a dual-monaural design with completely independent, yet physically identical channel modules, offering superior audio performance, better weight distribution, and greater reliability. In order to fully benefit from
the many features designed into this product, please take
time to read this entire manual before operating.
Caution: This product can deliver enough
energy to the output terminals to produce a lethal
shock. Do not attempt to wire the amplifier when
the power is turned on.
to hard clipping, overheating, excessive high frequency
energy, and output DC, thus preventing damage to the
amplifier or the load. Status LEDs indicate fault conditions, if any, and warn the operator of situations requiring
a change in operating environment.
The MF A amplifiers are compatible with all Ashly
Powercard input options, and are shipped standard with
balanced XLR, 1/4" TRS and screw terminal input connections, as well as 5-way binding post and Neutrik
Speakon speaker connections. Stereo, parallel mono, and
bridge mode switches along with a ground lift are all externally accessible on the back panel.
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.
Caution: The MFA amplifiers are capable
of delivering tremendous amounts of power to the
speaker load. Ashly Audio is not responsible for
speaker damage as a result of excessive power.
Caution: This unit is capable of producing high sound pressure levels. Continuous exposure to high sound pressure levels can cause permanent hearing impairment or loss. Use caution
when operating at high levels by wearing appropriate ear protection.
The MFA amplifiers employ complimentary bipolar output transistors to achieve maximum output current capability and power efficiency. All voltage gain
and current gain stages remain completely discrete and
fully complimentary for lowest distortion and superior
overload behavior.
In addition to the amplifier’s audio path, several
sophisticated monitoring and control circuits serve to keep
the amplifier running comfortably within its safe operating area, while protecting the speaker loads from abnormal conditions. This protection will intelligently respond
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 MFA amplifier is supplied with an AWG 12/
3 AC power cord, and should be plugged into a standard
3-wire grounded electrical outlet which supplies 120VAC
50-60 Hz , 15 Amps minimum (some export models are
wired for 240 volts and are labeled as such). Be certain
that there are no other high-current devices on your AC
line, as performance of both may be compromised. In the
event of line voltage sag, or “brown-out”, MFA amplifiers will continue to operate normally, albeit with less
power.
3.2 Current Requirements
A 15 amp circuit is usually sufficient for normal
operation into 8Ω or 4Ω 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
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Operating Manual - MFA-8000 and MFA-6000 Power Amplifier
peaking at the clipping level, the following AC line current capacities are recommended for system design purposes:
Load MFA-6000 MFA-8000
Idle 1 Amp 1.2 Amps
8Ω × 2 7.5 Amps 10 Amps
4Ω × 2 10 Amps 15 Amps
2Ω × 2 15 Amps 20 Amps
Table 3.1: Recommended AC line current capacity
Both MFA 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
T o 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 per centage of the load’s power rather than the total amplifier
output power, so that you can use this table to accurately
determine power loss 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.
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.
5. RACK-MOUNTING REQUIREMENTS
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 MFA 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.
5.1 Mechanical
All Ashly amps are designed to fit in standard 19inch 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
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 amplifier for cooling purposes. Thermal output of the amp is measured in max BTU/hour for
typical audio program material when both channels are
just peaking at the clipping level.
Load MFA-6000 MFA-8000
Idle 420 500
8Ω 1900 2420
4Ω 2300 3450
2Ω 4140 4830
Table 5.1: Maximum BTU/hour
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Operating Manual - MFA-8000 and MFA-6000 Power Amplifier
6. FRONT PANEL FEATURES
6.1 Power Switch
When the unit is switched on there is a 2 second
delay, during which time the PROTECT and LIMIT circuits will activate. The load is disconnected during this
power-up sequence, and the input signal is attenuated.
When turning off the amplifier, the load is removed instantly, and the protect and limit LEDs will briefly turn
on as the power supply discharges.
6.2 Output Meters
Output meters display peak output voltage in dB,
referenced to full output. For example, if full output in a
given configuration is 800 watts, then “0” on the LED display means the amp is delivering the full 800 watts to the
load, “-6” would mean the output is 6dB down, or 200
watts (-6dB is half the voltage, and power = voltage
squared divided by resistance ). If the line voltage sags,
the output meters will track the drop and accurately preserve the relationship between “dB below full output” and
actual clipping.
6.3 Clipping Indicator
The red CLIP LED is a true clip indicator, which
monitors the power supply as it is affected by the AC line
voltage and the speaker load. Clipping occurs when the
Channel One Output Level
-12-15-18-21-2 4-27-30
Limit
Thrm
Protect
-3-6-9
0(Clip )
AC Power
Off
signal peak levels extend beyond the available power supply rails, essentially “cutting off” the crest portion of the
waveform. This produces signal distortion, and can potentially damage drivers. The CLIP LED illuminates exactly at the onset of clipping.
6.4 Limit Indicator
This green LED indicates that the internal electronic limiter has activated, in the form of a signal attenuator. The intensity of the LED indicates the amount
of attenuation. The limiter circuit is activated by any of
the following conditions:
1. Turn-on delay for muting purposes
2. Severe output clipping
3. Excessive internal temperature (monitored at
two key points per channel)
4.
5. Excessive output current
6. Protect-mode muting
On
Abnormal high frequency/high amplitude signal
6
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