Trying to listen

Thanks to all for your information and help. I went in to the amp another time after I let it run for about an hour. Bias was steady at about 23.4 mv on one side and 22.8 on the other. So I adjusted again and got each channel back down to 22 mv. This time I left the multimeter on each test point for 15 minutes and made sure the reading was stable. It seems that kind of patience was something I should have employed from the outset. I will try and get my hands on a temp gun. Since then it has run warm but not hot over about 5 hours a day of listening (this is the unit I use in my office). The sound still astounds me. I have a number of units around the house and the only one that sounds better is a Scott 299b. And even then the sound is totally different. The Scott sounds like I am in the middle of live performance most of the time where the Sony sounds like there is someone inside the amp with a slide rule making sure every sound is 100% accurate. Again, appreciate all of the help. Coupled with the little klipsches and the st j60 tuner I am a pretty happy listener.

Thanks for your reply. Well, I would need help to understand how to measure that. I have pretty rudimentary skills in this area. I know how to set the Bias to spec and check the offset/balance readings tp ensure they are as close zero as I can get them. But, as I mentioned, not sure how to measure current. Thanks in advance for any information you can provide.

Hi folks, New member here. I just "reacquired " a 1980 sony ta f55 amp. I had one through the 80's but by 95 I had showed it enough disrespect that it gave up the ghost. It sounds really good, and it is gratifying to know I can still remember what I heard all those years ago. Back then I ran it through a pair of large advents but this time I am running it through a pair of rp150ms. It sounds even better. But it runs hot. I have reset the DC bias to factory spec (22 mv) and have the DC balance/offset fluttering around 1 mv off of zero and it seems like it is running somewhat cooler, but certainly not room temperature even at low volumes. This is a "heat pipe" amp, with an oil filled copper pipe strapped over the power transistors which are right on the main board running to what look like aluminium fins. Does anyone know if these amps tend to run hotter than the more traditionally cooled amps of that era? The thing sounds so good I would hate to have blow on me... Any help or opinions would be appreciated.