Hi
This post, I just saw as I am looking for a 121-C schematic.
I have two of these preamps to match up, one has a minor power supply problem.
If I can send a message to this member as I have worked on almost all of the vintage gear, and have done tube vintage for ages. I could help him out, and I could really use a schemo, although I can draw one out, just takes time.
I have years experience with the type of complex tube circuits Scott built.
POST
swing1951
Re: GREAT SCOTT!!! - It's NOT a Dynaco??? - H. H. Scott 121-C Preamplifier - DONE!
« Reply #63 on: 16 Apr 2013, 11:14 pm »Greetings from Reno.
Been working on one of these--complex bitch, especially for a newbie like me.
The pix no longer seem to be available on Google images, or anywhere else. Being able to view them would be a great visual aid for me. I did take digital photos myself of my 121c and tried to make some diagrams, mostly successfully. But I can't, for the life of me, seem to get the Range switch reconnected properly. Dynaural is involved, as is the rumble switch, and I've become hopelessly buggered up. 'Bout ready to heave it in a dumpster. No, not true. But I am severely frustrated. Wish Bill were still around. Does anyone have one of these HH Scott 121c preamps or is familiar with them?
I've studied and studied the schematic but it doesn't make a lot sense (to me--probably similar to a situation of one who doesn't know how to read music attempting to). In addition, in the few photos I've been able to find of the undersides of these devices, they seem to vary, in the wiring, the capacitors used, from unit to unit (same model--121c).
I did alright with a Scott 99D, recapping, installing new resistors where needed, and it sounds great, but it was a cakewalk by comparison. This preamp is infinitely more complex, even convoluted. Maybe I should take it to a pro, now that I've totally screwed it up.
Any comments or advice are welcome. Copies of the photos of Bill's work would be very welcome.
Thank you.
