Re: Quad 405-2 help
The dumping principle is a good one. Unfortunately the dreaded underrated 3.3k and dried out electrolytics (above a power resistor) are its nemesis.
And of course the output clamp. What a daft idea - all it does is kill a perfectly working amp before the fuses do their work.
The protection circuit was designed by an old friend of mine during a few years he worked for QUAD in the early 80's. At least you have the schematic - which was from the earliest versions that used discrete parts. It was later put into a hybrid-like potted part.
Teaching my grandmother and all that - but have you thought about laying out a little PCB rather than hard wiring?
Craig
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