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Old 23rd Jun 2022, 10:16 am   #1
qualityten
Octode
 
Join Date: Feb 2009
Location: Wallasey, UK.
Posts: 1,308
Default Heathkit S-99 distortion after operation

Earlier this year, I restored a badly rusted S-99, replacing all the capacitors, nearly all the resistors and the sockets on the power board. After members here helped me to catch a mistage on the bass control, I thought I had it all buttoned up, and I stored it away in a mostly clean and dry garage.

On returning to listen to it, I find that it has very mild distortion that gets worse after operating for an hour or two. I would describe the distortion as a burr in the sound.

Square wave testing on all the audio frequencies shows a clear trace, but this gets blurry at the edges as distortion sets in.

Because it is so awkward to trace a signal on the preamp board, I would be grateful for any thoughts on what might be causing this. Thank you.

David
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