I'm overhauling a Wards Airline head for a friend--this is the two 6L6GC version--and the tremolo seems a bit slow to me. This circuit doesn't use an LDR; it modulates the cathode voltage on a 12AX7 gain stage using another 12AX7 section as an LFO.
It has three capacitors in the oscillator circuit, two of which are the Z5U ceramic type, and I know that these can suffer aging effects: drift and/or increased ESR. It isn't hard simply to rebuild the entire circuit with new capacitors and resistors, but I was wondering how often this problem surfaces and whether it's usually the capacitors or the resistors. One nominally 150k resistor has drifted up to 170k.
Of course, the capacitors are marked 20% tolerance. The tremolo may always have been a bit off. The build quality was horrendous: four joints that were never soldered and several other joints I had to resolder to get rid of noise.
David
It has three capacitors in the oscillator circuit, two of which are the Z5U ceramic type, and I know that these can suffer aging effects: drift and/or increased ESR. It isn't hard simply to rebuild the entire circuit with new capacitors and resistors, but I was wondering how often this problem surfaces and whether it's usually the capacitors or the resistors. One nominally 150k resistor has drifted up to 170k.
Of course, the capacitors are marked 20% tolerance. The tremolo may always have been a bit off. The build quality was horrendous: four joints that were never soldered and several other joints I had to resolder to get rid of noise.
David
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