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Original Message
RE: New Tubes (6CA7)--now bias too high
Posted by daveap on February 11, 2016 at 13:19:56:
Thanks again, Peter. I cleaned and re-tensioned #5 to no avail. In doing a little research, it appears that a subset of the current production EH tubes that pass factory spec draw a high amount of plate current and cannot be biased in most EL34 amps. Tubestore.com apparently culls these and sells them at a discount. (see here: http://www.thetubestore.com/Tubes/EL34-6CA7-Tube-Types/Electro-Harmonix-EH6CA7-HPC ) The only thing I can think of is that I have a set that draws high current. If this is the case and, if I get stuck with the set, would it be possible to decrease the current by adding resistance on the B+ side?