[lens]

I just got a Van Alstine Model 1 preamp on Ebay. I wanted a simple preamp to go with my MC225 and this seems to be it, except that the power switch wiring has been buggered up. The "switched" outlet on the back and the preamp are on all the time and the ON/OFF switch only turns on the indicator light (why do people do this?). I want to put this thing back the way it's supposed to be. Even though it was hacked pretty badly, I think I can figure most of the intended wiring out, but the part that has me confused is that my guess about the original wiring would still have the preamp remaining powered all the time and the on/off switch only switching the switched outlet. I should say that my guess about what *should* be connected to what is only from staring at whats left and trying to create a schematic from cut wire ends, etc. It's seems weird that a commercial preamp would always be powered so I'd like to look at a real schematic if anyone has one, or info on how to get one. Also if anyone owns one of these I'd like to know what your power switch does.

[avahifi]

As I recall (its been over 25 years since I have seen one), the Model One actually was wired so that the internal circuits were on all the time, to prevent a large turn-on and/or turn/off thump from getting to the amplifier and speakers.  Dynaco also did this with their Dyna Pat-5 preamp.

The power switch should have controlled the switched AC outlets, but in some versions of the preamp the power switch controlled a solid state triac that supplied current to the AC outlets.  This protected the fragile AC contacts in the power switch.  If the triac blew, then it could have blown in the shorted mode, leaving the AC outlets on all the time.

I have no service info on this unit.  I was only with VA Systems for a short time.  After realizing that I had been included for the use of my name only and was outvoted on all policy issues, I sold my stock back and left the company.  I was supposed to get all current production models and service info on all models.  This never happened.

Regards,

Frank Van Alstine

[dB Cooper]

Just out of curiosity, I stumbled upon this link with a post from one of FVA's former business associates from that venture. Maybe he has some product info. Not surprisingly, he seems to remember the parting differently, and in any case both seem to have gone on to bigger and better things.