#1
ok so i got this crate gt-80 amp which is a hybrid amp, its old so id like to refresh the tubes as their probably pretty old. 2 of the 3 tubes are 12au7 and one is a 12ax7. is their any kinda upgrades as far as types of tubes or anything i could do to push a little more out of the amp?
#2
They Stock tubes? Then you can get more out of it if you get JJ or Sovteck tubes.
NT

BE QUICK OR BE DEAD SON
#4
Quote by LeviMan_2001
If you want more gain then replacing the 12au7 with a 12ax7 should do the trick there. But it doesn't sound like you have a ton of knowledge about tubes so you'd have to learn how to properly bias the 12ax7.

lol. preamp tubes are cathode-biased. they bias themselves. dont replace the 12AU7s with 12AX7s. there is probably a reason they are 12AU7 and not 12AX7.

TS, check out the ultimate tube thread in GG&A. lots of great info on makes.
#7
You'd have to adjust the resistors around the tube, A typical load line for a 12AU7 is 6800 ohms to 10k ohms. And an anode load for a 12AX7 is easily ten to twenty times this value. This also changes the cathode resistor needed for the same voltage offset at the cathode. 12AU7s typically use a good bit more current compared to the 12AX7.

The general consensus is that JJs are about as good as it gets for new production tubes, but check out the tube thread as Jim suggested.
#8
Quote by Invader Jim
lol. preamp tubes are cathode-biased. they bias themselves. dont replace the 12AU7s with 12AX7s. there is probably a reason they are 12AU7 and not 12AX7.

TS, check out the ultimate tube thread in GG&A. lots of great info on makes.


link? i looked but must have missed it