ATI DA208 Dual Distribution Amplifier, sn55950

A Balanced, stereo Audio DA, 1 RU package. Good Condition.
Beschikbaarheid:: Op voorraad

All ATI Products, from their Phono Preamps to the simplest DA, provide a combination of Professional features, Audiophile sound quality and superior construction.   We wholeheartedly recommend ANY of their products without reservation.

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


Here are some excerpts from the ATI manual.


OUTPUT LEVEL:  +24dBm into 600 ohm balanced loads.
THD: .001% typical, 20 – 20KHz.
IMD:  .05% maximum, SMPTE measurement.
SLEW RATE:   13 Volts per microsecond.
RESPONSE:    +/-. 25dB, 30 to 20,000Hz
NOISE:  -100dBm EIN 20Hz-20KHz
GAIN:   20dB maximum, each output has 40dB smooth adjustment range going to full off
CROSSTALK:   70dB minimum at 1KHz.
OUTPUT IMPEDANCE:   400 ohms balanced, 200 ohm single ended, split and RF bypassed, AC coupled.
INPUTS:     30K ohm active balanced, split and RIF bypassed.   +22dBm maximum input level.
HUM REJECTION:    70dB CMR at 60Hz
POWER:    115/230 VAC +10%, 47-63Hz, 12 VA.
SIZE:       19"W x 1-3/4"H x 7-1/2"D, 10 lbs.
TERMINALS:  Solder tabs on a removable terminal strip


Your DA208/416 provides two (DA208) or four (DA416) independent one in by four out circuit groups. A four way feed is sufficient for many applications, however, if you need more outputs, you can parallel channels by bridging several inputs across the same line for 1 x 8, 2 x 8 or 1 x 16 operation.   Since each input circuit has 30k ohm balanced input impedance, you can simply terminate your source line with a single 620-ohm resistor (if necessary) and then parallel as many inputs as necessary across it.

Each input can bridge line levels up to +24dBm without clipping. Common mode hum signals are attenuated by 70dB and the input resistor network is split and heavily bypassed for good protection from RF signals riding on the input lines. The input differential amplifier operates at slightly less than unity gain to optimize input headroom and to prevent any signal clipping from occurring prior to the gain controls.

Each output consists of an adjustable gain stage driving the HI output terminal along with a unity gain inverter stage. The inverter drives the LO output in opposite phase to provide an active balanced output. The adjustable gain stage utilizes a unique circuit arrangement that allows us to provide a smooth, full range logarithmic gain control for each output using a linear cermet potentiometer. This circuit provides 20dB gain at full clockwise rotation, unity gain in the 12 o'clock position and tapers smoothly to full off at the full CCW position.

Since we actually vary the gain of the output stage rather than taking the more conventional approach of adjusting the input level to a fixed gain stage, we can use the DA at low output levels with very little noise penalty. You can easily match the DA outputs to console medium level inputs (-20dBm) or to drive semi pro RCA inputs (single ended at. 10Vrms) without requiring outboard attenuator pads.
Each balanced output stage is isolated from the output terminals by DC blocking capacitors and 400 ohms of build out resistance. The build out resistors are split and bypassed to prevent any RF signals that might be picked up on a output line from feeding back into the DA.

Your DA has clipping indicators to warn you of overdriven and overloaded outputs. These indicators individually sense nonlinear operation of any output channel by measuring the error voltage at the feedback terminal of the HI side output amplifier. As long as the output stage operates linearly, the error voltage at it's negative input (for example WA pin 9) will remain very small. The onset of clipping, current limiting or even slew rate limiting immediately causes a large increase in this error signal, which is then fed through R25 to the error amplifier U5A at pin 13. U5A, in turn, drives the clipping LED through Q1. Feedback voltages also feed the error amplifier from three other output channels.
To allow maximum flexibility in grounding in high RF environments, the DA circuit grounds are isolated from case ground. For normal operation, add a ground jumper from the barrier strip ground terminal to the chassis ground screw.

We have taken measures to keep RF out of your DA. This includes split and bypassed input and output resistor networks, beaded, bypassed and isolated power inputs, non-concentric wound power transformers, and double ground plane PC boards. However, in a difficult broadcast application, any RF shielding and suppression system is going to be no better than the ground system into which it is trying to dump the unwanted RF. For optimal product performance, be sure to have a good grounding system.