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RE: EFB

Posted by 1973shovel on June 24, 2021 at 16:09:03:
I'm going to have to do some reading about the how and why of elevating filaments.

Below is a link to a more extensive discussion of DAK's LM337 failure in the EFB circuit. You suggested a protection diode per the LM337s data sheet, but I have yet to heed it. My SCA doesn't see much use, perhaps only a dozen hours since this discussion in 2018, but I've never had a bit of trouble with the LM337 in all the years its been in there.

I'm currently rebuilding the power supply of the SCA-35, as well as populating and installing Dave Gillespie's replacement amp boards, which optimize the circuit to use 6GH8A on the input instead of the previous 7199.

Since I'm in there anyway, now would be the time for me to add the diode to the EFB.