RE: Starting a Heathkit AA-32 after 40 Years. - Eli Duttman - Tubes Asylum

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RE: Starting a Heathkit AA-32 after 40 Years.

Eli Duttman

In Reply to: Starting a Heathkit AA-32 after 40 Years. posted by Andybot on August 12, 2012 at 14:31:42:

While not of good quality, a schematic can be found via the link provided below.

Jim McShane gave you the big hints. Switch to 6BQ5/EL84 O/P tubes and eliminate the tone controls. Build a proper DC heater supply for the phono section heaters that's energized by an additional filament trafo. The 600 mA. saved by doing that provide, and then some, for the heater current demands of 6BQ5s vis a vis 6GW8s If you use MOSFETs in the "concertina" phase splitter role, no additional socket(s) need be added to the chassis. ;>) Use 12AX7s where 6EU7s were OEM.

Rebuild the B+ PSU along the lines shown in the uploaded "El Cheapo" schematic. That's the right way to build a voltage doubler setup. While the Heath power trafo probably can't tolerate 820 μF. 'lytics in the doubler stack, it almost certainly can tolerate 150 μF. parts there. Reduce ripple and improve regulation.

The OEM SS diodes are NOISY. Replace them with UF4007s.

Eli D.
Heath AA-32 Schematic (Open in New Window)

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Follow Ups Full Thread

Topic - Starting a Heathkit AA-32 after 40 Years. - Andybot 14:31:42 08/12/12 (10)

RE: Starting a Heathkit AA-32 after 40 Years. - Eli Duttman 17:17:56 08/14/12 (0)

Heathkit AA-32 after 40 Years. In a box in my closet, unpoened - Chris O 17:18:13 08/13/12 (1)

Nice find! (nt) - 1973shovel 16:52:52 08/14/12 (0)

RE: Starting a Heathkit AA-32 after 40 Years. - Jim McShane 15:48:07 08/13/12 (4)

Jim, I'm kinda with BC here - FenderLover 17:55:24 08/14/12 (0)

The tubes are probably good - bcguitar 08:10:21 08/14/12 (0)

RE: Starting a Heathkit AA-32 after 40 Years. - Andybot 21:53:28 08/13/12 (0)

RE: Starting a Heathkit AA-32 after 40 Years. - Eli Duttman 17:44:00 08/13/12 (0)

RE: Starting a Heathkit AA-32 after 40 Years. - Neff 04:58:25 08/13/12 (0)

RE: Starting a Heathkit AA-32 after 40 Years. - Eli Duttman 19:36:54 08/12/12 (0)

Follow Ups

RE: Starting a Heathkit AA-32 after 40 Years. - Eli Duttman 17:17:56 08/14/12 (0)

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