[Boatanchors] Vacuum tube op-amps

[David Ross]

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    ross@hypertools.com