Joe Sousa schrieb: 

Hi Terry, 

Thanks for writing back. 

The excellent closeup photos that were added recently were contributed by Philbrick enthusiast Achim Dassow from Switzerland. As a result of Achim's contributions, we have been having an intersesting exchange about early amplifier design for voltage regulators. I plan to edit the results of the conversation and post it.

I copied Bob Pease in case he would like to talk about the point-to-point wiring of the modular opamps. It is odd tha the lowest cost tube opamp of the Philbrick line, the K2-W, around $22, was never converted to a PCB.

Bob Pease:

***  I  was  never  involved  in the  production  design  of the  K2-W  or other  high-volume  op-amps.  I think the  components  were  wrapped  around  some  stainless-steel  pins,  soldered,  and  then slid off the pins,  and  tacked  to the  plug and  sockets. I was never  consulted.  We did use  PC  boards in my SK2-V and -P.   I don't  expect to comment  more  later -  I'm not very knowledgeable.

Joe Sousa:

I have seen (nearly) verbatim copies of the K2-W in the Heathkit HR-19 5-opamp manifold, and in an ultra rare Embree module I got on ebay.