Archive for discrete transistor

CBS Volumax Limiter Mods

Posted in Modded with tags , , , , , , on December 29, 2012 by AnalogAudioRepair

This was a project for a client from Brazil – modding a CBS Stereo Volumax discrete transistor limiter.  The Volumax is a two band limiter with transformers in and out.  You can do fun stuff like turn off the high or low frequency limiting, vary the HF level, change the release times, and much more.  This was a pretty standard mod that also included XLR in and out.  Amazing units when you do a bit of work to them!


DuKane 2A81 Compressor Mods

Posted in Modded with tags , , , , , , , , on November 28, 2012 by AnalogAudioRepair

Here are a pair of vintage DuKane compressor/limiters.  They use an all discrete transistor circuit path with a FET for gain control.  They come stock with a (useless) noise gate, two inputs, and some controls on the rear panel.  These mods remove the noise gate, move the ratio and bypass to the front, and add release time settings.  Everything gets cleaned up and boards are re-capped if needed.  The results?  “A super smash box” according to one user!

Acoustic 126 Bass Amp

Posted in Repaired with tags , , , , , on October 15, 2012 by AnalogAudioRepair

This is a vintage Acoustic Control Corp. model 126 bass amplifier.  I received it non-functioning with no power cord or fuse cap.  Replaced two output transistors, re-soldered an inductor in the EQ section, and cleaned the heck out of the pots and sliders.  Added a new power cord and fuse cap and it fired right up.  These ’70s Acoustic heads really sound good!

Universal Audio 1108 & 508

Posted in Racked Modules, Restored with tags , , , , , , , , , , , , , on October 7, 2012 by AnalogAudioRepair

This is a set of vintage Universal Audio (UA / Urei) 1108 discrete transistor microphone preamplifiers with matching 508 passive equalizers.  The preamps are transformer in and out and sound amazing.  The EQs use passive capacitors and inductors for simple but smooth EQ.  Restored and racked with phantom power and gain pots.

Yamaha PM1000

Posted in Modded, Racked Modules with tags , , , , , , , , , , , on September 19, 2012 by AnalogAudioRepair

Yamaha PM1000 discrete transistor console strips cut down, recapped, modded, and racked as mic pres with EQ.

Telefunken W95C EQ

Posted in Racked Modules with tags , , , , , on August 5, 2012 by AnalogAudioRepair

Single Telefunken W95C discrete equalizer module.  Racked with power supply and XLR in/out.

RCA BA-31 Preamps

Posted in Racked Modules with tags , , , , , , on August 5, 2012 by AnalogAudioRepair

A pair of vintage RCA BA-31 discrete transistor microphone preamps with Daven output attenuators.