C Audio RA1001 Service

Just done a service on one these old C Audio RA1001 amplifiers. UK made Mosfet outputs. Sounds very good! Plenty of potential to add more MOSFETS and filter caps. Needed the fan oiled, cleaned, a few dry joints, new caps and slight damage to a trace needed repair. Clearly this one has had been repaired in the past. New zobel resistors been installed (oscillation problem perhaps in his history)

It's a shame many of the PA amplifier manufacturers moved away from MOSFETS. HH Electronic, C Audio, BK Electronics, Citronic... All UK made.

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Exicon and SML

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Potential of a short on metal cable stay coming away from board.

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Trace repair

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LED very bad dry joint!
 
If the MOSFET manufacturers would continue to produce the MOSFETs I'll bet the amp manufacturers would make more MOSFET amps. Carvin here in the States produced a whole line of FET amps then the manufacturer stopped making the MOSFETs. The BJT manufacturers are still making the same or suitable subs from the 70s, don't know why the FET factories can't do the same. It's probably all about the $$$$$$$.

Craig