Orban Optimod 2200. 

These are still nice sounding units and work just fine in many markets.  They don’t breathe fire, but it’s tough to make one sound truly bad.  When they do it’s often op amp.  failure.  This one had several. 


The Burr Brown amplifiers have been out of production for a while now.  I have a few left but the supply is dwindling.  

Valley Audio


Valley Audio 401 Mike processors.  Long out of production but they still get the job done. 


 Mountain Dew.  It’s always Mountain Dew. 


Most equipment has a weak spot and this is the 401’s.  The voltage regulator heat sinks are held on with nylon hardware.  Nylon hardware becomes brittle when subjected to heat over time.   The heat sink comes loose and the regulators overheat.  If we are lucky the failure stops there.  If not the op-amps are next. 


A hot air rework gun makes these fairly simple to repair.  And a magnifying glass to see that you’ve got things aligned. 





 Symetrix 528E Mike Processors.   These are good sounding units but switch failure is  common.  Depending on which switch, the unit can stop functioning entirely.  Often cleaning them with a good contact cleaner is enough to restore things, other times you have to replace them. There are at least three generations of circuitry represented in this stack,  with various changes and improvements over the years.