Made the biggest difference ever

Dynaco-Doctor Forum

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Posted by xaudiomanx (A) on February 9, 2018 at 08:11:40

Just got done with my two year project(mostly in waiting). I built a huge power supply for the ST-70 using my own formulas and doings with my vast but sometimes dumb logic, but things I learned over the years. The only thing I kept stock was the input board and the output tubes. Even the filament supply was over sized with its own filament transformer. I had the HV B+ power tranny custom wound.

The whole project was a huge success but costly. I totally eliminated all the power supply from the original amp and used a power cord from an outside power supply on its own chassis. The filtering on the power supply chassis is a standard R/C with no choke.

I guess, except for the input board, this is not a Dynaco anymore. I call it a "Schwartzaco". Not my main and reference amp as I am not a favorite of push/pull amps but it was an experiment I always wanted to try based on some suggestions from friends and techs I know.

Looking at the amp you can't tell it was modified except for the power cord going from the power supply chassis to the amp chassis. The input board was a new one but the original circuit using updated parts. The capacitance for each stage was increased a small amount. Nothing drastic?

As for the sound? Way more open and detailed than you could ever possibly get from a standard Dynaco. Most of these so-called modifications all deal with everything and anything(input board, caps, tube rolling, etc.) but no one ever addresses the power tranny which is the first and foremost component in anything. And probably the most important.

This all can be put back to stock very easily with about an hours time and a soldering iron. No extra holes were needed to be made.

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Topic - Made the biggest difference ever - xaudiomanx 08:11:40 02/09/18 (17)

RE: Made the biggest difference ever - Mushroom Soup 18:45:30 03/05/21 (0)

Nice! - 1973shovel 16:53:03 02/15/18 (12)

RE: Nice! - xaudiomanx 14:45:01 02/18/18 (11)

RE: "getting rid of that anemic choke" - 1973shovel 05:41:41 02/24/18 (10)

RE: "getting rid of that anemic choke" - xaudiomanx 19:24:02 03/02/18 (9)

RE: "Those guys are the best" - 1973shovel 09:48:51 03/03/18 (8)

RE: "Those guys are the best" - xaudiomanx 13:45:19 03/03/18 (7)

RE: "it is not a Dynaco any more" - 1973shovel 04:42:02 03/04/18 (6)

RE: "it is not a Dynaco any more" - xaudiomanx 16:59:39 03/05/18 (5)

If I ever run out of projects - 1973shovel 05:59:28 03/06/18 (4)

RE: If I ever run out of projects - xaudiomanx 07:28:50 03/06/18 (1)

If I recall correctly - 1973shovel 12:33:00 03/06/18 (0)

RE: If I ever run out of projects - xaudiomanx 07:24:29 03/06/18 (1)

Someone gave me a Lafayette - 1973shovel 13:15:04 03/06/18 (0)

Congrats! Pics please.... - viridian 19:41:32 02/11/18 (2)

RE: Congrats! Pics please.... - xaudiomanx 19:51:16 02/11/18 (1)

RE: Congrats! Pics please.... - DANIL 20:00:57 07/24/19 (0)

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