Van Alstine MOSFET Amp Info Wanted

[kve777]

I picked up this "Dynaco Mystery Amp" from a fellow AK'er recently and found the boards are VanAlsine PC-489, and the outputs are Hitachi 2SK134 and 2SJ49 MOSFET's, but can't seem to find out anything more about it, like a model # or specs. Apparently it's about 55 WPC or so, based on the output devices. I just wish I had a model # or something to verify. It's in a Dynaco ST-150 cabinet, I believe. Any info would be appreciated.

 

[Pio1980]

Maybe move this to the AVA forum.

 

[luvvinvinyl]

I can vouch for that.

I can move this thread for you, if you wish.

 

[kve777]

Bump for info.

 

[avahifi]

Well! That is certainly an interesting but unauthorized use of AVA circuits. We never built anything like that in a Dyna ST-150 chassis.

It appears that the AVA circuit boards, and Dyna SCA-80 heat sinks with our Hitachi mosfets installed have been removed from an older Dyna chassis and cobbled into this Dyna St-150 chassis. The toroid power transformer is not ours either and I have no idea of its current or voltage rating.

I also note that the audio circuits are missing output inductors and critical output circuit damping networds, so its stability is suspect. Here is a more representitive photo of what a real AVA circuit set in a Dyna ST-150 should look like.

Frank Van Alstine