ok, bought some 12ax7(groove tubes, and oh, this is my first stab at preamp tube replacement, so i am clueless)for my crate turbo valve. heres what i did, i unplugged the amp and pulled the old tubes out, then put the new ones in, simple. then i let it sit with the power on for 25 min(basically the same way you would replace power tubes), when i kicked the standby off, it screamed like a maniac, even with the volume completely down. did i do something wrong and ruin my tubes, or could they just be shitty tubes?i noticed they dont glow as bright as my old tubes(also 12ax7)any suggestions?
preamp tube replacement help!
- Thread starter bloodsoakedchevy
- Start date
Strigoi
Member
Sounds like possibly you have a microphonic tube, try replacing the preamp tubes one at a time to see if it's a particular tube. Depending on how the tubes are made sometimes you can't see the filaments glow as well. The Sovtek 12AX7LPS for example don't look like they're glowing at all.
it came stock with sovtec 12ax7, and one chinese 12au7. i did crack an old one puting it back in before i bought the new ones, and tryed to run it anyway, but i got no sound from the amp whatso ever. maybe that dumb mistake messed my amp up. i put 4 of my old tubes back in and tryed all the new ones one at a time. it still screamed, maybe guitar center sold me all shitty tubes? i think ill go back there friday and take them out to dinner and make them pay the bill.hahahahah.
xenophobe
Active Member
I wouldn't put it past Guitar Center to do something like that.
Next time buy from:
www.tubestore.com
Next time buy from:
www.tubestore.com
Strigoi
Member
tubestore.com is definately a good place to get tubes, I hate paying the shipping from Canada though. You can also try eurotubes.com if you like JJ's. At least now you can tell your friends that your amp screams 
ggggrrrrrrrrrrrrrrrrr!!!!!!! i just got my new sovtec 12ax7lps that i bought from thetubestore.com, plugged them in and the same thing happened!!!!!!!!! im lost!
