Replace your power tubes when:
- amp loses volume
- amp becomes noisy
- certain functions become inop(example, no reverb, clean channel works, or no lead channel)
- amp powers up, all tubes are lit, but no sound
- amp is blowing fuses
Replace Preamp tubes when:
- The tone is microphonic
- The sound is cutting in and out
- No sound is coming out at all
- Sound is static
Which Preamp tubes are recomended
- Any 12AX7, 7025, 12AT7, 12AU7, or 12AY7 can be used in any position except the reverb driver tube.
- For reverb driver, use 12AT7 or 5751
Which Poweramp tubes can I use in my ampThis depends on the type of amp and the wattage range! It is recommended to only use exact replacement tubes similar to what is installed at the factory. Be careful when deciding to install other types of 6L6, 6V6, or EL-34 based tubes. Not all have the same specs and some can’t handle the plate voltage of the amp. Below is a list of comparable tube types: 6L6: 6L6GC, 7581, 5881 6V6: 6V6S, 6V6GT EL-34: 6CA7
I get no sound out of my amp: Check your cable connections and then check the pre and power tubes. The fuse keeps blowing: Most likely one of the power tubes has gone bad. If you have installed a new set and reset the bias and the fuse is still blowing please contact the service dept. There is a crackling or “ocean” type static coming from the amp: Sound is being generated by one of the tubes. Easiest way to trouble shoot is to use a new tube for the preamp section. Swap one tube at a time. If noise goes away the tube you pulled is bad and can be discarded. If you go through all the preamp tubes and still have noise you will need to purchase a new set of output tubes and install them. Rebias and check. If noise is gone then you have found the bad tube.