I have had one microphonic tube that you could hear the effect thru the speakers and when tapping. Right now I have a matched set of 6SN7GTB’s that are microphonic when tapped only. They sound wonderful, and the problem is due to the luck of the draw from the vendor, but microphonic after only a few months is getting expensive.
@rfogel8
This is very interesting information. I’ve had a red base RCA 5692 go bad, plus a pair of VT-231 went bad. So far these are my favorite, and are expensive.
I think I will order a pair of new production tubes so that I have a spare set. Any recommendations for non-Chinese tubes with good imaging and smooth highs?
FYI, classical music.
@rfogel8
For example, a couple positions in the MP-1 require a 6SN7 GTB because it can handle higher plate voltages. Using a 6SN7GT, VT-231 or 5692 which can’t handle the higher voltage will most likely cause an early death.
This is very interesting information. I’ve had a red base RCA 5692 go bad, plus a pair of VT-231 went bad. So far these are my favorite, and are expensive.
I think I will order a pair of new production tubes so that I have a spare set. Any recommendations for non-Chinese tubes with good imaging and smooth highs?
FYI, classical music.