Archive for amplifier

Zim-Gar Vintage Transistor Amp

Posted in Modded, Repaired, Restored with tags , , , , , , , on May 4, 2013 by AnalogAudioRepair

This is a funny little solid state amp I bought from a fellow on Craig’s List.  I bought it “as-is” and it hummed and made noise but passed no signal.  At first I thought it was Japanese, but when I took off the back panel there was a tiny schematic marked “Paris Corp. Salina, Kansas”!  I replaced the first transistor which took care of the noise and lack of signal, but the tremolo wasn’t working.  I rebuilt that section with some new caps and a resistor and dug up a vintage footswitch to turn it on and off.  The power supply filter cap had already been replaced so I can only think that the amp has always had some hum (it was certainly not high-end when new).  Adding a second stage of filtering killed the hum and made this into something that could actually be used.  Honestly it was more work than the amp is probably worth, but a fun project nonetheless!

Zim Gar Front

Zim Gar Front

Zim Gar Panel

Zim Gar Panel

Zim Gar Panel

Zim Gar Panel

Zim Gar Schematic

Zim Gar Schematic

Zim-Gar Guts

Zim-Gar Guts

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Fender Re-Issue Amp Repairs

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

I recently serviced a pair of Fender Re-Issue tube amps from the 1990’s.  One was a Deluxe Reverb with a shorted output tube, the other a Vibrolux with a blown cap (literally).  These ’90s re-issues are much like their predecessors, but with printed circuit boards which make it a bit more of a pain to work on them.  At least the Deluxe has connectors for the front panel controls rather than soldered wires like the Vibroverb!  It had some 2 watt resistors that were so charred they almost burned through the PCB.  I had to scrape away as much carbon as possible and seal the board with epoxy before replacing the resistors and power tube.  The Vibrolux had a capacitor which actually burst and both amps had very weak Chinese made 12AT7s.  While I was in the Deluxe I added the de-clicking cap to the vibrato circuit.

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!

Sovtek Mig 100

Posted in Repaired with tags , , , , , on August 6, 2012 by AnalogAudioRepair

Sovtek Mig 100 vintage tube guitar amplifier.  Fixed hum issues, tweaked, and SOLD.