In 1988, I bought an amp, I'm not sure of the model. (1.5t,1.0t)... Unfortunately, I sold that amp a while ago. That amp had a "mono" switch on the back of it. You had to unscrew a little metal plate to switch it on "mono".
Recently, I bought an m1.5t and a m1.0t and they don't have that switch. Does anybody knows why?? What model was the amp I'm referring to? I was sure it was an m1.0t but the one I have don't have that switch... ???