I own this 04 BDR.....right off the bat, the treble affects the volume a LOT, much more than any of my other amps. The mid and bass control seem to do little as well. Is this common with this amp? Also, the volume taper is not like many describe, its seems more gradual than many folks say & it is a 250k pot. This amp was biased at around 50% with the stock Sovtek 5881 (which I don't particularly care for)..... I set the bias around 70% and it seems punchier..... Still....that pesky treble control seems to really affect volume on both channels....unless the treble is at least on 5 to 7, the amp lacks volume. Since the amp has low plate volts (420 to 430 range) I may go ahead and try some real Tung Sol 5881 out of my horde to get sweeter breakup at lower volume. This amp is LOUD........but it does not sound as good as my 71 SFSR at low volumes. I will definitely try some different speakers (I have a bunch). The stock speaker appears to be the one used widely by Fender with the multi ribbed cone.....kind of a Jensen C12N type possibly.