I just stumbled across this forum and would appreciate any help anyone is able to offer. I am the proud owner of a Spectral DMA-180 amp and a DMC-20 preamp. I have owned both pieces for about 5 years. I use the preamp on a regular basis and like it a great deal. The problem I am having is with the amp. My tech has it at his shop. The problem he is having is with the bias in one of the channels. I have contacted the manufacturer and am unable to get a schematic and I am not sure they would be willing to work on an older product like my amplifier. I would greatly appreciate a schematic, or in the alternative, if there is someone who knows these amps well that could provide counsel and instruction to my tech, I would be willing to compensate you for your time. My tech is top notch so it would not amount to a drawn out trouble shooting session. Please feel free to contact me through the forum of by PM. Thanks in advance.