Best Tubes for a Peavey Classic 30 Guitar Amplifier December 7th, 2008 When these tubes started to die, I decided to upgrade. I read all the articles on tube substitution, familiarized myself with the characteristics of each, and bought up one or more of all the ones that sounded interesting. The tubes I tried were (all Groove Tubes Brand): - Groove tubes EL84 silver and gold series. White and red classes. - 12AX7C (x1) - New Chinese tube...known for low noise, and rounded high frequency. - 12AX7-R (Silver) (x3) - Russian 12AX7 - Edgy and harsh. - 5751-M (x1) - Alternate 12AX7 design with about 80% gain, creamier tone, and early break-up. (Stevie Ray Vaughn uses these.) - 12AT7 (x1) - Low gain 12AX7...often thought to produce a smoother less distorted tone. I found they sounded muffled. - 12AY7 (x2) - Precursor to the 12AX7. Lower gain tube, with some other interesting characteristics such as clearer treble and stronger bass. And here's what worked: First I start with a solid set of power tubes: Groove Tubes Gold Series EL84s, 5 rating (red) are sufficient for me. All my pre-amp tubes are Gold Series as well. Entry tube (tube closest to the input jack): 12AY7 gives by far the lowest noise, clearest and most harmonically pleasing tone here. This tube is the most essential to get right. A 5751-M sounds OK here but I found it sounded slightly muddy and distorted...but it would be my second choice. If this tube isn't right, nothing will sound very good. Driver tube (tube closest to the power tubes): This tube is important as well, because it is a hard working tube, not as sensitive to noise, but needs to hold up under higher power signals. Again, I found a 12AY7 was the best sounding here. But Playing live with high volume you're going to be pushing your normal volume dial past half-way to get enough volume to compete with a rhythm section. Still, if you have a reasonably hot set of pickups, you'll be fine. (Tele pickups, humbuckers, and strat pickups give plenty of level.) I don't recommend 12AX7C for this position because they sound muddy here, but if you do happen to run out of volume control sweep, it's probably going to be the best substitute with higher gain. I don't recommend a 12AX7-R here because they have too much treble, and are too noisy. And while my second choice would be a 12AT7 for tone, I find they are slightly less clear than the 12AY7, enough that it's pretty noticeable when you turn things up. Distortion driver tube (middle tube in the pre-amp): It took a lot of tries to get a tube that sounded good in this position. It depends on the other two tubes a lot. You need something with plenty of gain, but that also resonates reasonably well with the other driver tube, and the pre-amp tube, and it needs to be low in noise. I settled on a 12AX7C which gives by far the smoothest distortion, without being too harsh or dissonant, and doesn't drive the noise level too high. My second choice if all you use is the distortion channel would be 3 12AX7-R tubes. This combo is insanely edgy, but very noisy, and potentially very harsh. Plus you'll lose most of the good qualities of your clean tone. |