I saw the comments about biasing the heater circuit of a 6GH8A or 7199 with relation to the cathode bias. I have a stock ST-70 with 7199s that test with weak emission. I have a stock of (51) 6GH8A tubes to select from and would like to convert to those. Aside from making some cuts to traces under the board and reconnecting to the appropriate pins plus the heater biasing issue, are there any other component changes that are needed when doing the conversion?
Thanks in advance.