I've kinda come to a crossroads amp-wise. I've been using my SM900 for quite some time now and while it isn't plagued by thermal shutdown, it has other issues like a noisey eq section (don't even think about dialing up any highs on the parametric eq or the hissing will be louder than ur bass), a fairly loud 60 cycle hum and underlying distorted overtones that creep in during sustained notes especially when playing harmonics (I've had it serviced for this twice and both times it was blamed on a bad cap, but the fix was only temporary at best and it would eventually return). All this happens even with a new preamp tube. So the question is, do I stay the course or is it time to move on to another brand/setup? The SM900 is a great sounding head, but the reliability issues are getting annoying and from what I've heard these amps are like graphite necks...if u get a bad one, good luck fixing it. I've been looking @ the Carvin bx1500 and even some Hartke HA stuff since they both have tone shaping capabilities similar to the SM900 (I don't like having just a bass, mid and treble knob...not enough flexibility), but I have no way to try either one b4 making a purchase decision. Thoughts?