It was a pleasure to do some restoration work on such a nice top of the line Pioneer power amp. This SPEC 4 amp was sent to HV HiFi from Virginia and on early visual inspection we found venting filter capacitors. This has been becoming the norm for many of these big amps from the 70’s and 80’s. Due to the leakage we did not want to push the amp to its limits for fear of catastrophic failure. We instead disassembled the amp and restored the meter board along with the amp boards, before installing four new Chemi-con 0.22F filter caps which fit into the existing clamps. Our usual mix of Panasonic and Elna caps were used. Elna Silmic II were used for electrolytics in the signal path.
When complete this amp really rocks. Bass response is tight and precise. It was broken in on several pairs of speakers and none of them caused the amp to break a sweat. Amplifier alignment as always was adjusted after the work performed and then checked before the unit is packed to go home. This was a treat to have in the shop and was compared to a few other amps we have for demo that are in the same league and were in competition almost 40 years ago. That’s a review for another day but the SPEC 4 was really impressive in it’s ability to play almost all genres of music without deficiency. Here’s a few shots.
Meter Board before and after :
Amp board before and after :
New filters installed and amp alignment performed :