Im new hear and thought i would come to a smaller site to chat and just learn about tube audio. I have been into audio since about 16yrs old and now 62 and recently retired. I have built a couple pair of Klipsch like speakers that turned out quit well. Bought my first tube amp in 2002. I now have a 300B that has had a few needed mods. I have a question, i have 2 Cryotone 6sn7 that have gone microphonic after 150hrs. I have emailed Cryotone/Wathen several times to no avail. The tubes make crackling noises intermittently when amp at idle. I do not hear this with music playing, even in the quite passages. Using a 300B. Anyone else here have this issue? I have many of their tubes in phono pre, 12sn7 and line pre 12sn7, also rec tubes and no issues with those tubes. Very quite tubes. Would issue be something that might go away with time?
6sn7 going microphonic after 150+hrs
- Thread starter Bluefish
- Start date
Are they crackling, or microphonic?
They have a crackle intermittently. I just cleaned the tube pins again as someone suggested with a q tip and drill using chrome polish, then deoxit. Seems to have helped. Just gonna let the amp idle awhile and see if the issue continues.
Crackling is not microphonics. Microphonics is when you tap on the tube and you can hear your tapping coming out of the piece of equipment. Crackling can indeed just be dirty tube pins. Be careful not to let deoxit get into your tube sockets!
so far so good. I tiny bit of intermittent crackle, but hardly noticeable. I plan on rolling some 300b's today just for giggles. WE300, EH300 treated and sophia electric princess mesh plates. Will see how the 6sn7's are doing by end of day because they seem to get worse with heat.
The tube noise from the 6sn7 has subsided quite a bit. Hardy noticeable now. Tub rolling went well. The WE300B B stock are my 3rd favorite. They have a very strong mid. Growling electric guitars come across nicely with this tube. The EH300B does everything right top to bottom, well balanced. SE 300B mesh has the most magic of the 3 in my opinion. Very robust on the bottom.
Only one 6sn7 making intermittent noise at idle. Sounds like sizzling bacon.
