Q: Changing Trace Elliot Velocette power tubes

12/28/1999 2:45 AM

Barry

Q: Changing Trace Elliot Velocette power tubes I am about to start fiddling with different power tubes in my Trace Elliot Velocette 12R. It uses a pair of EL84s in "advertised" Class A mode. That was an attempt to avoid the unavoidable discussion about pure Class A. This is the model with the pentode/triode mode switch.     Anyway, I have no schematic and no sales literature that discusses tube changing precautions. Need I be concerned with bias? What should I check and how?     I regularly change tubes and set the bias in my other amps but not being an amp techie I would like to know first if I should check anything whilst in there. The amp came with Sovtek El84s. While it actually sounds quite good as is, I want to try some Ei and JJ tubes.     I never worry about it in my Champs, but that's because (within reason) I am under the impression it isn't an issue due to the cathode biasing scheme. If I have that wrong flame away =)     Thanks for any help.       Barry