Altec 1612A Limiter Amplifier (Modified & Recapped)


This 1591A has been refurbished in our workshops as follows:

  • Audio board recapped
  • Electrolytics in the audio path upgraded with higher-value bipolar caps
  • Power supply recapped
  • Pots & switches cleaned
  • Modified for shorter release times
  • Voltage switched to 220 Volts for use in UK & EU
  • New UK plug fitted (Euro plug available on request)
  • XLR output socket fitted on rear panel

This Altec 1612A preamp / limiter dates from the mid-1970s.  It’s a two-input device with separate gain controls for each input and a switchable FET-based limiter. Sensitivity is set by plug-in preamplifier or transformer modules. There’s plenty of gain available on each channel and it’s suitable as a mic or DI preamp

The limiter has an on / off switch and a limit / line control to match levels when the limiter is in circuit. When driven hard the limiter is capable of super-audible compression. With the limiter disabled the preamp can be overdriven to produce lots of harmonic niceness, so there is plenty of colour available from this big green box

Limiter attack / release times are fixed but switchable between 10µs / 0.8s (fast) and 33µs / 2.8s (slow).  10µs attack times are well into UREI 1176 territory – it’s a FET limiter party trick to be able to respond so quickly. FET compressors are the Muhammed Ali of compressors – turn the light out and they’ll be in bed before the room goes dark. I am experimenting with faster release times – enquire for details

I’ve modified this limiter with an upgraded power supply and a recapped audio board feeding a new XLR output socket on the back panel. The original output terminal strip is still in place and offers various impedance taps on the output transformer

The unit is supplied with two input modules: one a Peerless line  bridging transformer and the other an active preamplifier with 12 dB gain. There’s more than enough gain available to use the 1612A as a mic preamp for dynamic or ribbon mics. Condensor mics will require an external phantom power source

These Altec limiters offer a characterful alternative to clean modern recording gear. With transformer-coupled inputs, transistor circuitry and a fairly unsubtle FET limiter the 1612 A is capable of generating all kinds of overdriven sounds. Use it on a snare mic or room mic to add heft & character or try it on bass guitar – it won’t sound like anything else you own

“The 1612a is a lots of color thing”

“It’s a really awesome sounding unit that can be cleaned up with some better caps and power supply filtering”

“But its got tons of flavor and its one of my favorite units on bass, kick, drum, electric guitar and the occasional metal vocal”

“For serious baseball announcer squish, exploding bass and guitars and major cymbal/snare battle ..try an Altec 1612a.. they are still around for kinda cheep… very thick and meaty”

“I L O V E it on Bass, Guitars, and if I want the OH really pumping (which is not really very often) it is the one.. it is my go to for overdrive lead GTR and in your face bass…”

“+1 on the Altecs. I have a 1612B that I use on rock vocals all the time. Love it!”

FET compressor with two-input preamplifier. Inputs are on XLR connectors & output is via a terminal strips (XLR pigtail supplied). Switched to 220 Volt for UK / EU. Captive power cable with new UK power plug - EU plug supplied on request. Supplied with two input modules - one transformer and one preamp
Standard, shallow 2U rack device

Gearslutz discussion


In good used condition, particularly for a vintage piece. This 1612A has all original knobs & switches and is pretty much unmarked.  Tested & working 100%. Modified & recapped. Supplied with two input preamp / transformers (mic & line) and a short XLR output pigtails(the standard connection is on a terminal strip). Photos to follow

Vintage Gear All vintage gear will have case scratches and marks. It may also have, or develop, noisy pots and switches. I make my descriptions as accurate as possible and note any existing defects. I test each item before shipping, and and supply a test sheet for it, but please understand that vintage gear will not be perfect and adjust your expectations accordingly