[Boatanchors] Vacuum tube op-amps

Mon, 07 Jul 2003 10:40:14 -0400

If anyone is interested I have a copy of a GAP\R model K2-W Operational
amplifier sheet.  It is a two page description with schematics,
applications, etc.  George A. Philbrick Researches, Inc., 285 Columbus
Avenue, Boston 16, MA.  I used to have two of the plug in units but that
was decades ago.  Don't know if they are still around or not.

73,

Bill, K3PGB

AI2Q wrote:
> 
> Hi Dave:
> 
> I have one of these 2-tube Philbrick op-amps, NIB in my collection. If
> anyone's interested, I'll post a JPEG or two of it and its box on my Web
> site in the near future.
> 
> Vy 73, AI2Q, Alex in Kennebunk, Maine
> http://users.adelphia.net/~alexmm/ai2q.htm
> 
>  .-.-.
> 
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of David Ross
> Sent: Sunday, July 06, 2003 2:09 PM
> To: [email protected]
> Subject: [Boatanchors] Vacuum tube op-amps
> 
> BAfolks -
> 
>   Some links to interesting articles on vacuum tube op-amps here:
> http://www.national.com/rap/vacuumtubes.html
> 
>   From the Philbrick K2-XA data sheet:
> 
>   "The open loop dc gain for normal operation with a +/- 60 volt swing
> and a 50K load is 30,000.  With a +/- 110 volt swing the gain may
> decrease to 10,000.  With these units, computing devices of nearly all
> speeds can be assembled with a minimum of external circuitry."
>   "The K2-XA needs a seasoning period of about 100 hours of operation.
> Then, under optimum conditions typically found in analog computer
> installations, and after temperatures have been equalized, the drift
> rate of the typical K2-XA will average about +/- 8 millivolts per day."
> 
> Dave Ross    N7EPI    [email protected]
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