Man, what a haul! 🙂 You're going to have a lot of fun with these, for sure. Glad to see you're using the old light bulb hack on initial power-up; that bodes well for your future safety.
Hi dtener-
Don't know if you still have these, but thought this info might help. Recently posted on the tube collector's yahoo group-
"....Grommes later made a 100 Watt amp using PP-Paralel 6GT5's Had a flaw - over voltage on the first Filter Cap. We fixed this with 330VAC motor starting caps. Never lost one with that fix that also filtered out some line voltage spikes. Used several for Dolby Stereo conversions of Chicago area Mono Cinemas in the 70 -80's...."
Looking at the schematic, I believe he is referring to the 40µf 500v cap off the top of the main power supply diode bridge. 330VAC has a lower DC rating (330 x 1.4 = 462vdc) and I would not advise. However, a 600vdc oil cap there would be more reliable over time.
Don't know if you still have these, but thought this info might help. Recently posted on the tube collector's yahoo group-
"....Grommes later made a 100 Watt amp using PP-Paralel 6GT5's Had a flaw - over voltage on the first Filter Cap. We fixed this with 330VAC motor starting caps. Never lost one with that fix that also filtered out some line voltage spikes. Used several for Dolby Stereo conversions of Chicago area Mono Cinemas in the 70 -80's...."
Looking at the schematic, I believe he is referring to the 40µf 500v cap off the top of the main power supply diode bridge. 330VAC has a lower DC rating (330 x 1.4 = 462vdc) and I would not advise. However, a 600vdc oil cap there would be more reliable over time.
I just saw this. Thanks a lot. and yes I still have them. They are put on the back burner for right now but I am going to start working on them and I was rereading this thread. Thanks again.
Also I have found out from a person on Facebook that worked for Grommes when these where being made that what I have are not 101A amps. They are 102's that is why they are missing the small 3rd choke seen on the 101's. I can not find a schematic on these but they are very close to the 101's.
Good! Glad you found the info useful. Hope you get them running sometime. I know what you mean by back burner! Too many amps to fix..... 🙂
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