ATI M-1000-1 Dual Mic Preamp

ATI M1000-1 is a high quality dual Mic Preamplifier in a half-rack package. VG condition.
Availability: In stock
Manufacturer: ATI

The ATI M-1000-1 is a precision, Dual mic preamplifier with the following features:

  • Balanced inputs and outputs
  • Transformer coupled outputs
  • High RF and Noise immunity
  • +4 db level line output reference
  • High Slew rate for low TID
  • +22 dbm output level

From the Folks at ATI (Please note that this information is offered as a general description for this Model, and includes information that does not apply to this version.) :

This (preamp) 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 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. 

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.  Transformer Output (M1000-1, L1000-1) may have either HI or LO outputs grounded (but not both).   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.

Never heard of ATI?  They've been building high quality, bulletproof gear for the Broadcast industry for more than 30 years.  bibbtek has been installing their products in places ranging from Edit suites and Audio Production Studios to Conference rooms and School Auditoriums, with a remarkably low failure rate.

We love this stuff.   This gear is very well constructed and designed by folks who know the business of delivering high quality audio dependably, in high RF environments without compromise.

We have DAs that remain in continuous service that were installed in 1981!

Want to know more?  Check them out at


GAIN  71dB minimum
Microphone: -16dBm, 125mVrms
124dBm EIN with 150 ohm source and 20kHz measurement bandwith. Yields 74dB S/N ratio with -50dBm microphone input.
Microphone: 150 ohm source, 2500 ohm input  transformer isolated
.1% maximum THD at +20dBm output and input levels from -52 to -18dBm, 30-20,000Hz.
13 Volts per microsecond for minimum TIM
-70dB maximum at 10kHz.
80dB for common mode hum.
+48VDC at 4MA through 3,300 ohms and center tapped**
115/230VAC +/- 10%, 47-63Hz, 10VA.
in. (mm) 8.5 (216) W x 1.75 (44.5) H x 7 (178)

**Please note: this is a very early model and does not have phantom power.