It's a 1977 2103. Anode voltage measures 475. I'm out of adjustment on the trim pot at around about a maximum 16ma of anode current. The amp is a UK spec model, running EL34s. The previous owner had these changed to a new set of JJs before selling the amp to me. The grid leak resistors are 220k (and measure 222k), the resistor running into the bias trim pot is 56k (and measures 55k). The trim pot has a clean sweep from 0k up to 23 and a bit k. My meter and bias probe work fine (I checked them on another amp to be sure).
The only slightly odd thing I've found is that the speaker impedance was set to 8k but the twin McKenzie speakers measure 4k. It could well have been set like this since it was built for all I know. I corrected it. I am now at the limit of my knowledge/diagnostic abilities. I don't really want to go piggybacking resistors as that would be addressing the symptoms rather than the cause. Can anybody advise me on what to do next?
The only slightly odd thing I've found is that the speaker impedance was set to 8k but the twin McKenzie speakers measure 4k. It could well have been set like this since it was built for all I know. I corrected it. I am now at the limit of my knowledge/diagnostic abilities. I don't really want to go piggybacking resistors as that would be addressing the symptoms rather than the cause. Can anybody advise me on what to do next?
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