In Reply to: I have no explanation for that. nt posted by Tre' on March 30, 2021 at 17:27:00:
I removed some carbon comp grid stoppers from the 6SN7 driver stage relay sockets on my breadboard.My ARTA test setup uses a 100K pot to trim voltage coming out of the sound card. It is housed in a plastic box with rca jacks for in/out.
For some reason, I am getting odd THD readings from on the left channel, so I think the grid might be going into oscillation as I turn the pot.
A test signal directly from the soundcard into the amp causes no problems.
I will have to investigate further and try to input cap mod again.
DT 667Edit : found an issue related to power supply returns.
Once corrected, ARTA measurements seemed to normalize.
I will need to re-test the input cap mod again.
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- RE: It might be ... - deathtube 667 04/1/2102:51:42 04/1/21 (0)