vintasonic
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- Sep 29, 2023
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Hi
Wrestling with a Solo 100 head on my bench that is very noisy with 120hz hum, I think (but am totally not sure at this point) that it may have something to do with the heater voltage for V1&V2. The +/-3 volt lines are a little low, +2.9, -2.5 and look a little wonky on the scope. I have already replace the filter caps, the 4.5v zener seems to be ok (the 1.5v center is 2.0v so 4.5v total) Pulling V1 & V2 makes the noise go away, turning down master volumes makes noise go away, noise is in all three channels
Also, the schematic shows a 39 ohm resistor from the center of the second set of 10000uf to ground, which I can't find and if I measure from the -3v to ground it doesn't show as 39ohms, it measures as open.
Does anyone have better schemos or info than what I have? Any other suggestions are very welcome, this one is a bit of a head scratcher.
Thanks
Wrestling with a Solo 100 head on my bench that is very noisy with 120hz hum, I think (but am totally not sure at this point) that it may have something to do with the heater voltage for V1&V2. The +/-3 volt lines are a little low, +2.9, -2.5 and look a little wonky on the scope. I have already replace the filter caps, the 4.5v zener seems to be ok (the 1.5v center is 2.0v so 4.5v total) Pulling V1 & V2 makes the noise go away, turning down master volumes makes noise go away, noise is in all three channels
Also, the schematic shows a 39 ohm resistor from the center of the second set of 10000uf to ground, which I can't find and if I measure from the -3v to ground it doesn't show as 39ohms, it measures as open.
Does anyone have better schemos or info than what I have? Any other suggestions are very welcome, this one is a bit of a head scratcher.
Thanks
