I'm repairing/restoring this same model. The main issue I've found is that many resistors are way out of spec. But of course I had to replace those "can" capacitors with modern electrolytics.
@@daystromaudio1903 There is no point because it could never be there, it is highly improbable. If the primary was shorted to the secondary you would have full 390 volts B+ on the secondary (speaker outputs) which would short since one side connects to chassis ground.
Hello! This model looks nearly identical to the AA-100 tube amplifier, but yours is a slightly newer model with transistors. The tubed amplifiers are in higher demand, but I've seen these for sale for between $150 - $450. The electronics in these old amps usually have gone bad with age and need restoration. The upper end prices are overinflated in my opinion, considering the condition of most of them. Thanks for writing!
Good to see another amp rescued
I recognize an Ollie's sticker when I see one! (on the new tablecloth)
I'm repairing/restoring this same model. The main issue I've found is that many resistors are way out of spec.
But of course I had to replace those "can" capacitors with modern electrolytics.
Thank you for sharing your expertise. A had a HK AA-151 included N/C in a recent purchase of a metal press. I am inspired!
Sounds like a great deal. The AA-151 is a sweet amp.
The original schematic is horrific but such a cool piece.
Especially the part where they drew the switch matrix! Man, that's enough to tie your brain in knots...
Your opinion about ceramic capacitors in the signal path please: changing to pp-foil or not, that is the question!
How expensive is such a good repair-upgrade for that amp? Good work Sir! :)
About $400'ish if there are no bad tubes.
@@daystromaudio1903 Thank you!
You can’t see DC voltage across an output transformers output. It can’t pass DC. That is a test for transistor sets.
That's the point of the test. It better not be there!
@@daystromaudio1903 There is no point because it could never be there, it is highly improbable. If the primary was shorted to the secondary you would have full 390 volts B+ on the secondary (speaker outputs) which would short since one side connects to chassis ground.
Can you tell me what a Heathkit AA-21D is worth? I have one that was my dads and not sure what to do with it or what it’s worth.
Hello! This model looks nearly identical to the AA-100 tube amplifier, but yours is a slightly newer model with transistors. The tubed amplifiers are in higher demand, but I've seen these for sale for between $150 - $450. The electronics in these old amps usually have gone bad with age and need restoration. The upper end prices are overinflated in my opinion, considering the condition of most of them. Thanks for writing!
@@daystromaudio1903 thank you! Are you interested in buying it?
@@jkmhlewis You can reach me at pcbgraphix@gmail.com