JM
Ex Member
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OK, here's the story. After months of on-off sputtering, the left channel of my SE84B died. It wasn't a tube, I checked that straight away, and I couldn't see any broken solder joints or damaged components when I opened the chassis. Sending back the amp across the Atlantic to Decware was a bit of a problem for me.
Eventually I took the amp to a competent audio electronics person, closer to where I live. Power stage is OK, he told me, let's check the input stage. Eureka! The left 47k plate resistor didn't work...yet it looked absolutely fine. He couldn't find a matched pair of 47k's in his box of resistors (surplus from the aeronautics industry) but 42k would do. Would I be able to hear the difference? Barely, he said, perhaps a small improvement in dynamics.
Which I do hear, along with an improvement in clarity. My reference in the comparison, though, is an amp that had been running for a while with a damaged half. Even when it wasn't sputtering, I think the bad resistor had been playing up with the overall sound in some subtle way.
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