Heathkit A-9C Amplifiers

[Thermion]

Does anybody have any experience with this amp? I recently bought three of these, but I'm having trouble finding good (i.e. free) information on these amps. Here is the URL to the Heathkit museum page.
http://www.heathkit-museum.com/hifi/hvma-9c.shtml

The potted transformers look very nice. One drawback is the lack of UL taps on the output. These amps used PP 6L6 tubes which is perfect because I am planning to use the iron and chassis to build a couple of PP 1625 monoblocks.

Does anyone have any information on the transformer specs? They are probably military surplus, and have date codes from the early fifties. I am also having trouble finding a clear high resolution schematic.

I gutted two of them over the weekend, so I can start doing some tests on the transformers.

Regards,
JT

[kheper]

A schematic and specs can be found here:

http://nekhbet.com/a-9a.zip

Hold on. It is for an a9a not an a9c.


A schematic for the a9c, but not the highest resolution.

http://nekhbet.com/a-9c.gif

[erichayes]

Jonathon, if you want to send me one, I can analyze it and ship it back to you, along with the data (that was a long sentence).

[EWBrown]

THe two most common 6L6 OPT primary impedances of that era were 6600 ohms CT and 9K CT, these values are given in the older tube manuals and the ARRL Amateur Radio Handbooks. Should be good for around 25-30 watts output.

/ed B