[QuadList] Transistors for Ampex AVR-2?

[Don Norwood]

Hi Steve:

I have long believed that the VR-1200 is the more serviceable machine.  Yes, 
there are germanium transistors, and silicon transistors, and even early 
IC's in the 1200, depending on what vintage you have.  Remember that the 
1200 was made for over 10 years, and through that time, there were a number 
of changes.  For instance, later versions of Intersync have major 
differences from their earlier cousins.  Bottom line though, is that you 
probably have zero chance of replacing a custom IC in the AVR with anything 
other than the original part, while you can make circuit changes to 
accommodate silicon instead of germanium transistors.  All of that being 
said, whichever model you choose, it's a good idea to have at least one 
spare machine which can be a parts donor.  Remember that most of the 
mechanical parts are also unobtanium.

Another consideration is what your application for the machine will be.  The 
"standard" AVR-2 is a high-band only machine.  There were versions that 
could accommodate super-high-band, and versions that could play 
low-band-color.  I don't believe there were ever any for low-band-mono.  So, 
if you need to deal with a variety of standards, the 1200 is much more 
versatile as they were all LBM/LBC/HBC machines.  The only thing the 1200 
will not do is SHB.

But back to the heart of your question about parts availability, in addition 
to spare machines, I also have a stock of spare parts for all the Ampex 
machines.  While I'm not in the business of selling parts, I'm always 
willing to help out other users in need.  There are also general replacement 
transistors which work just fine in most situations where the original Ampex 
part is not available.  There are a few critical areas where care must be 
exercised when substituting parts, but most modern components far exceed the 
specs of the original parts.

One last point, there can be considerable differences in the reliability of 
either model, depending on how they have been maintained in the past.  I've 
seen machines that were pristine, and machines that have been butchered.  If 
at all possible, inspect a machine before you buy it to see how it has been 
treated.

Don

----- Original Message ----- 
From: "Steve Davis" <sdavis at crawford.com>
To: <quadlist at quadvideotapegroup.com>
Sent: Tuesday, February 10, 2009 7:01 PM
Subject: [QuadList] Transistors for Ampex AVR-2?


We are weighing the purchase of an Ampex AVR-2 vs. an Ampex VR-1200.  The 
AVR-2 is loaded with proprietary IC chips which are an obvious concern for 
replacement if (when) they fail.  The AVR-2 is more versatile and uses 
discrete components on the boards so it is ostensibly more straightforward 
to repair.  However, the transistors are germanium, which are hard to come 
by in 2009.  Does anyone have an opinion on this and, better yet, does 
anyone have a good source for replacement components for the AVR-2?

Many thanks,
Steve Davis







--------------------------------------------------------------------------------


> _______________________________________________
> Please trim posts to relevant info when replying!
> Send QuadList list posts to QuadList at quadvideotapegroup.com
> Your subscribe, unsubscribe and digest options are here:
> http://mail.quadvideotapegroup.com/mailman/listinfo/quadlist_quadvideotapegroup.com