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Heathkit AA-100 gets new power amp board

V

volvogv

Member
IMG_20171226_141710.jpg

Guys,

Last year I made a new circuit board to replace my broken factory board. I had some extra boards left over and several people asked to buy them. I threw together a parts package and made them into kits and sent them all out the door. End of story right? Wrong. After turning away a lot of requests I realized that there's still a need for these and decided to get back to work. I revised the artwork to make a few improvements over the last version. I don't want to make a big deal about this but if anybody with an AA-100 or AA-50 needs to replace the PCB, it can be done.

Here's my restoration blog: https://aa100restoration.wordpress.com/

How-to videos:
Introduction:
Building the PCB:
Installing the PCB:
Startup and bias adjustment:
 
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awesome. I don't own one of these, but I do own another old piece of gear that could truly stand a new pair of boards so I appreciate those who put forth the effort to make such things.
 
I'm a happy owner of one of these boards. Now we just need volvogv to make a replacement preamp board too.;)
 
Dandy said:
I'm a happy owner of one of these boards. Now we just need volvogv to make a replacement preamp board too.;)
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Yep. I've had far more trouble with the preamp board (especially with broken traces near the controls) than with the power amp board...

Regards,
Gordon.
 
Just like the other guys, where were you when i had a 100??
But, i am glad that you plugged the gap or filled the need.
But, why address an amp that has other limiting factors which prevent it from reaching true top gun status. If i may suggest, an amp that absolutely needs a new circuit board designed is the Knight KB85 and its mono sister, the Basic 25. If you decide to do a new circuit board for that amp i would get 4 pieces. Happy New Year to all.
 
trainbuftony said:
I have scrapped 2 of these for the iron. This kinda makes me wish I'd've at least kept the chassis. Nice work!
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I have the AA50 and like its looks very much, but the chassis is a pita. I understand the reason for the level adjustment pots, but they are mostly just something to degrade the signal, the RCA sockets under the chassis are really inconvenient and the cover is very awkward to pull on and off.
 
My own AA-100 had been rebuilt entirely 5 years ago following the GordonW mod thread. All caps and resistors, added bias pots. Unfortunately, these new boards weren't available at the time so there's a lot of wire jumpers on mine. It wasn't enough however as the AA-100 suffers from random hum or crackling related to socket traces and flaky connections on the various pots and switches. It has sentimental value for me as it was my first tube amp and it was property of my father. If it wasn't for this sole reason, I would had kept the iron and completely stripped down an rebuilt the damn thing...
 
Patrice B said:
My own AA-100 had been rebuilt entirely 5 years ago following the GordonW mod thread. All caps and resistors, added bias pots. Unfortunately, these new boards weren't available at the time so there's a lot of wire jumpers on mine. It wasn't enough however as the AA-100 suffers from random hum or crackling related to socket traces and flaky connections on the various pots and switches. It has sentimental value for me as it was my first tube amp and it was property of my father. If it wasn't for this sole reason, I would had kept the iron and completely stripped down an rebuilt the damn thing...
Click to expand...
I feel for you as i also have a Dynaco ST70/PAS combo that was from my father in law. It was such a rust bucket that i had to paint the chrome with hammertone paint, with a brush! The horror! the horror!
But with some triode electronics boards and top notch coupling caps it sounds good. But it makes me nostalgic thinking about it and so it is safely stored.
 
Guys, I want to throw this out there......
It's been my pleasure to be able serve the hobby by creating affordable Power Amp replacement kits for the AA-100/AA-50 and I'm very thankful to many folks who have built and installed them.
We all know that the pre-amp section of the AA-100 is horrible with its open wafer switches and PCB traces that crack, break, peel off. Lately I've been thinking about designing a new pre-amp retrofit kit to complement the Power amp kit. This would also be a drop-in replacement and a vast improvement over what is there now.

Does anybody know where I can get a dead or junked out AA-100 chassis that I can get really cheap that I can use as a mechanical test bed for designing a new Pre-amp? All I really need is the bare chassis and faceplates. Alternatively if somebody is willing to loan me a chassis, I'd be glad to return it after the engineering work is done.
 
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