Heads Up! Van Alstine Model One preamp and Model 2 poweramp

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Toni Rambold

Re: Heads Up! Van Alstine Model One preamp and Model 2 poweramp
« Reply #20 on: 14 Sep 2018, 12:05 pm »
… These are the Biasing Instructions:






the bias adjust potis on the boards are the outer ones. the inner ones
are called offset trim - you have to ask my old master of electrical engineering
what that means.


hope i could help - Regards Toni

avahifi

Re: Heads Up! Van Alstine Model One preamp and Model 2 poweramp
« Reply #21 on: 14 Sep 2018, 03:52 pm »
When you replace those old power supply electrolytic capacitors, you are going to have to be creative.

The problem is that new electrolyics have gained vastly in volumetric efficiency over the years.  A capacitor of the same capacitance and voltage rating is now MUCH smaller physically than the ones made 30+ years ago.  This is a good thing, except in your case.

The Model 2 was designed for specific physical size capacitors to provide support for the audio circuit boards.  These capacitors are now long gone.  You will find the right value and voltage ratings at DigiKey or Mouser, but you will need to add connection wires to get their terminals to the audio boards as they will be much smaller.

Frank

dB Cooper

Re: Heads Up! Van Alstine Model One preamp and Model 2 poweramp
« Reply #22 on: 15 Sep 2018, 03:20 am »
Wow, this thread was started almost ten years ago....

Toni Rambold

Re: Heads Up! Van Alstine Model One preamp and Model 2 poweramp
« Reply #23 on: 15 Sep 2018, 11:45 am »
 :lol: ... no, it started almost 40 years ago, when a magazine in his January 1979 issue

introduced the three van alstine components:



... sorry for the cutout !

Remember the good old days:

A pair of Magnepan Tympani 1D for $1395, a Model Two for $800 and a Model One for $600 -

and you could live happily ever after !