restorer-john
Grand Contributor
HK receiver
Amplifier. It has no tuner.
HK receiver
ahh rightO... I see it now. That makes it even more worthy of a proper rebuild.Amplifier. It has no tuner.
Wow, four fuses. Is one fuse per speaker a common arrangement?
Looks like @almico is about to become intimately knowledgeable with his HK receiver.
Do not start poking around with capacitors- you are wasting your time and will likely cause problems you don't have right now. There are absolutely no capacitors in the signal line from input to output when main direct mode (-7dB) is engaged and the amplifier is ruler flat from 0.5Hz-well over 120KHz. Before you do anything. At all. Test the amplifier. What you are describing is either a) your imagination or b) the other amplifier is non-linear to the point it is audible.
What are the chances that power supply filter caps are dried and so lack of bass and loud passages and so not sounding good. ?So I hooked up the PM660 into my main system and poop, it's sounds like crap. Now I know what grainy means. Compared to the 3W/ch single-ended cathode follower tube amp I've been using, it sounded horrible. It gets loud, but the sound is unbearable. I ordered most of the caps for the driver and power stage and have some homework to do.
sorry just read this. My newbie suggestion would be to run it for some more time so other caps in the circuit reform and then replace filter capacitors. If still not sounding good replace again with original.I was thinking about testing the filter caps first. It sounds nice at low volumes but craps out when it gets pushed. It could be a power supply issue? I can't test them in the circuit, but I can easily pull one and test it.
sorry just read this. My newbie suggestion would be to run it for some more time so other caps in the circuit reform and then replace filter capacitors. If still not sounding good replace again with original.
Regards.
I would follow @restorer-john advice first. But since you asked, I'll explain this procedure anyway.... I just downloaded REW again. I even still have the MiniDSP mike that I bought years ago when this was an obsession. I used to to sweep speakers and my room, but never an amp. Not sure how that works. I have a little Lab-2 scope that I can blow the dust off of.