I have been using this amp for a little over a year now, it's super punchy, and usually makes even a cheap bass sound phat... But lately it has been giving me this buzzy hissy sound, like distortion from too hot of a signal. I have the crossover all the way down, and cut treble freqs to help alleviate the issue, but it is still there, and of course losing those trebs makes tapping sound less full. Think its time to replace the preamp tube? It sounds cleaner on the FET channel, but I loves me that tube channel. FWIW I use tube compression (EHX Black Finger) as the first effect in my signal chain, to a MXR Blow Torch, to a Qtron, then chorus, tuner into the amp. All responses appreciated!