I've just acquired an El Toro and it is quite a beast. However, one thing I have noticed is that the bass pot is acting more like a switch than a pot. Full on and you get lashings of bass, but there's this definite point about 20% of the way round where the bass just "disappears" and the travel after that seems to have little or no effect. I've tried squirting some Servisol in the pots and giving them a good wind back and forth, but while that did chase out the crackles it has not helped with this behaviour. Do you think there's something wrong with the pot? Time to source a new 1 Meg reverse log?
The other thing I've noticed is that the active preamp is pretty noisy when the treble is up full - and curiously the hiss comes through the amp even when the volume is turned down to zero. It's fine if you have the treble at around 80%. I did read somewhere that someone replaced their opamp chip, might this help?
Don't worry, I'll get some pics up soon