ATI Technologies M1000 Operating And Maintenance Manual

Category
Musical Equipment
Type
Operating And Maintenance Manual

ATI Technologies M1000 is a professional-grade dual microphone amplifier designed for high-quality audio applications. With a gain of 71dB and a maximum output of +22dBm into 600 ohms, it can amplify even the weakest signals without distortion. The M1000 features a transformerless design with a slew rate of 13 volts per microsecond, eliminating transient intermodulation distortion. It also has a low-noise input stage and a high output swing capability, making it ideal for driving long cable runs without signal degradation.

ATI Technologies M1000 is a professional-grade dual microphone amplifier designed for high-quality audio applications. With a gain of 71dB and a maximum output of +22dBm into 600 ohms, it can amplify even the weakest signals without distortion. The M1000 features a transformerless design with a slew rate of 13 volts per microsecond, eliminating transient intermodulation distortion. It also has a low-noise input stage and a high output swing capability, making it ideal for driving long cable runs without signal degradation.

Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
© Copyright 1997-2005, Audio Technologies Incorporated - Printed in USA
M1000
DUAL MICROPHONE AMPLIFIER
OPERATING AND MAINTENANCE MANUAL
Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
DESCRIPTION
This section is strictly written to boost the designer’s ego by letting him tell you of
some of the clever things we have done inside the MicroAmp. It may be skipped
by anyone having anything better to do.
For many years engineers (ourselves included) have been using operational
amplifier ICs in audio circuitry. These ICs, developed primarily for the
instrumentation market, had many shortcomings when used in high quality audio
applications. The lack of audio related specifications, crossover distortion, high
noise for low source impedances, limited output capability and limited gain
bandwidth product forced many compromises when used in high gain audio
systems. High ratio input transformers, output boost stages and multiple stage
designs were all used to compensate for op amp deficiencies and in turn added
additional response and distortion problems of their own.
Walter Jung in a definitive series of articles' analyzed and defined slew rate
induced distortion mechanisms, tested many commonly available ICs and
correlated various distortion tests with subjective (listening) criteria. A very
significant result of his efforts was the identification of an IC originally developed
for the European professional audio market which has almost ideal
characteristics for audio use and in particular provides a high rate capability of 13
volts /microsecond, virtually eliminating slew induced Transient Intermodulation
Distortion. By contrast the old standard 741-op amp has a slew rate of only
.6V/microsecond.
This op amp is now available from several U.S. Manufacturers in single and dual
versions and forms the basis for our MicroAmp designs. This chip incorporates a
low noise input stage designed for excellent noise performance even with low
source impedances thus eliminating the necessity for touchy 1:20 input step up
transformers in the M1000. High output capable of driving 600 ohm loads directly
to +22dBm with total freedom from crossover distortion, high inherent linearity,
100 dB open loop gain and 50Mhz gain bandwidth product make this an ideal
device for highest quality audio. The absence of Transient Intermodulation
Distortion may be detected in the smooth effortless high frequency output
capability, the absence of the harsh, raspy sound typical of IC amplifiers driven to
full output at high frequencies and the freedom from increasing harmonic
distortion vs. frequency. As used in the MicroAmp a minimum of 40 dB of loop
gain is available for 100:1 distortion reduction even at 20 kHz.
The high output swing capability allows the amplifier to use a simple, low
distortion, flat response 1:1 output transformer. ATI provides three models of
each MicroAmp; Transformer outputs (with faraday interwinding shields) for high
RF field environments, a balanced differential output stage version (bridge circuit)
for low RF environments where balanced output lines are required for hum
rejection in long runs and the minor performance degradations of an output
Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
transformer are not desirable and a simpler, lower cost single ended
(unbalanced) output stage version with full +22dBm, 600 ohm drive capability for
use in low RF environments for short line runs.
Inaudible crosstalk characteristics allow use of the M1000 for either Stereo or
Dual Monaural applications. A dual concentric gain control is provided to facilitate
either mode of operation. Only minimal coordination is requited to grasp both
concentric knobs simultaneously for stereo use.
Our power supply incorporates a couple of unique regulating devices called
zener diodes. In contrast to most fancy three terminal IC regulators, these
devices will live through line transients and simultaneously protect your
expensive circuitry.
INSTALLATION
Your MicroAmp may be desk mounted on its non-slip suction cup feet and left out
for everyone to see since it's so pretty. You can stack the amplifiers on top of
each other. We don't recommend stacking more than 30 high on a desk since it
is difficult to reach the top.
Rack mounting kits are available for your amplifier. P/N 20021-501 mounts a
single MicroAmp in 1-3/4" of vertical rack space. P/N 20024-501 mounts two
amps side-by-side in 1-3/4 inches.
MicroAmp mounting kit P/N 20090-501 allows a MicroAmp to be mounted under
a desktop or behind a cut out.
WIRING
Our insurance company insists on three wire grounded plugs. The third wire
ground can cause a ground loop with your station ground. If you are sure your
station ground will provide adequate protection to personnel in case of an AC line
short to the chassis, a 3 to 2 AC line adapter can be used to isolate the power
line ground. We recommend that the adapter be removed and the power line
ground reconnected prior to any service work requiring removal of the station
ground connection from the MicroAmp chassis.
The four inch copper strap which you are of course using for your station ground
is not going to fit around the #6 chassis ground screw on the MicroAmp rear
panel. Run strap to within a few inches of the chassis and jump to the chassis
ground with shield braid.
Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
Microphone inputs and outputs use XLR type connectors and require mating
plugs. The applicable input plugs are Switchcraft A3M or equivalent. The output
plugs are Switchcraft A3F or equivalent. Mike wiring is conventional, hi (in phase)
to pin 2, Lo (out of phase) to Pin 3, Shield to pin 1. Either 150 ohm or 50-ohm
microphones can be connected to the MicroAmp without modification.
The MicroAmp M1000 will accept microphone outputs up to 125 mVrms (-14dBm
available power/150 ohms) without distortion.
Output wiring is indicated on the rear panel label. HI outputs are in phase with
each other and with the input signal.
Transformer Output (M1000-1, L1000-1) may have either HI or LO outputs
grounded (but not both).
CAUTION: Balanced differential output (M1000-2, L1000-2) has active drivers for
both HI and LO outputs terminals. DO NOT GROUND either HI or LO terminals.
To drive an unbalanced (one side grounded) Load, connect it between HI and
GND terminals and let the LO terminal float. Two separate 600 ohm unbalanced
loads can be driven from each output without interaction by connecting one
between HI and GND and the other from LO to GND. The two loads thus driven
will be out of phase with each other. Individual grounds are provided for CH l/left
and CH 2/right outputs.
ADJUSTMENTS
The MicroAmp has sufficient gain and output capability to overdrive some
console inputs particularly those providing preamps for high-level input channels.
A -50dBm available power microphone output (2.5 mVrms) will provide +8dBm
output with the gain pot set to two o'clock position. 12 o'clock is approximately
OdBm and 10 o'clock is -10dBm output. Operation with the MicroAmp pot set
below 10 o'clock position degrades noise performance and a fixed attenuator pad
should be placed between the MicroAmp output and the Console input to allow
MicroAmp operation at around 2 o'clock.
MAINTENANCE NOTES
Power supply voltages are + and - 18 VDC nominal, dropping to +/16 VDC under
full output. Maximum allowable voltages are +/- 22 VDC (limited by IC). If zeners
are replaced, remove Al, A2, and A3 ICs and check output voltage before
plugging ICs back into the circuit. Remove power when inserting or removing
ICs.
Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
IC output DC voltages (no signal conditions) should measure 0 VDC +/- .5 VDC.
Significant deviation indicates IC or circuit problem. Measurable DC difference
between +/- amplifier inputs (other than due to meter loading) indicates IC failure.
Five to ten years hence, replace aluminum electrolytics in power supply.
Keep 250 W soldering guns out of the MicroAmp.
If hit by lightning, replace Al through A3.
MODIFICATIONS
230 VAC OPERATION
Your amp is wired for 115 VAC 50/60 Hz operations unless otherwise requested
at the time of ordering. It can be modified for 230 VAC use by removing the
Power transformer primary jumpers W1 and W3 and inserting a jumper in the W2
holes.
150-OHM OUTPUT IMPEDANCE
Transformer output M1000s are converted to drive 150 ohm audio lines by
removing jumpers W4 and W5 located adjacent to output transformers T3 and T2
respectively. Insert two new jumpers for each output transformer between the
original jumper terminals and the empty terminals immediately adjacent to and in
line with the original terminals in order to parallel the secondary windings.
Balanced differential output and single ended output will drive 150 ohm loads
without modification but will current limit before full supply swing is reached.
INPUT CENTER TAP
The center taps of the input transformer primary are available on the PC board
next to the transformers and are labeled CT. They may be grounded by adding
jumpers between each CT point and the adjacent empty holes.
INCREASED GAIN
Additional gain can be provided for low output boom mikes by raising feedback
resistors R21 and R40 (M1000-1, -3) from 220K to 680K ohms (10 dB increase).
The M1000-2 requires that R21 and R40 be increased to 330 K ohms and also
R45 and R49 be increased to 820 K ohms for a 10 dB gain increase.
Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
SPECIFICATION
GAIN 71dB minimum
MAXIMUM INPUT Microphone: -16dBm, 125mVrms
MAXIMUM OUTPUT +22dBm/600 ohms (M1000-1, -1P).
+24dBm/600 ohm (M1000-2, -2P)
NOISE OUTPUT 124dBm EIN with 150 ohm source and 20kHz
measurement bandwith. Yields 74dB S/N ratio
with -50dBm microphone input.
INPUT IMPEDANCE Microphone: 150 ohm source, 2500 ohm input
transformer isolated
DISTORTION .1% maximum THD at +20dBm output and
input levels from -52 to -18dBm, 30-20,000Hz.
SLEW RATE 13 Volts per microsecond for minimum TIM
CROSSTALK -70dB maximum at 10kHz.
HUM REJECTION 80dB for common mode hum.
PHANTOM POWER +48VDC at 4MA through 3,300 ohms and
center tapped input transformer. Switch
controlled.
POWER 115/230VAC +/- 10%, 47-63Hz, 10VA.
DIMENSIONS in. (mm) 8.5 (216) W x 1.75 (44.5) H x 7 (178)
D, 4lbs, ( .176Kg).
MOUNTING Suction feet for non-slip desk mounting. Rack
mount kits; 20021-501 mounts a single
centered unit, 20024-501 mounts two units
side by side.
CONNECTORS XLR type in and out
WARRANTY Limited, One Year Warranty
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ATI Technologies M1000 Operating And Maintenance Manual

Category
Musical Equipment
Type
Operating And Maintenance Manual

ATI Technologies M1000 is a professional-grade dual microphone amplifier designed for high-quality audio applications. With a gain of 71dB and a maximum output of +22dBm into 600 ohms, it can amplify even the weakest signals without distortion. The M1000 features a transformerless design with a slew rate of 13 volts per microsecond, eliminating transient intermodulation distortion. It also has a low-noise input stage and a high output swing capability, making it ideal for driving long cable runs without signal degradation.

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