Hi all, After reading about the MC225 since I was a teenager, I finally bought one, in absolutely beautiful condition, with tube cage, and even original McIntosh branded output tubes. I received it today, replaced the 5751 that was in the first position with a tele smooth 12AX7. The 12AU7s were mismatched so I put in some RCA clear tops. I left in the pair of sylvania 12BH7s - they matched each other and had nice black plates. I opened up the amp and everything in there is original and clean. So on a whim I plugged in a source and a pair of test speakers and put it on a variac. I brought it up to voltage slowly until the filaments hit 6V and checked voltages. Everything was close, and NO hum or buzzing at the speakers - just the slightest tube rush hiss. I took it up all the way to 6.3 volts and the same. The only voltages more than a few percent off are at pin 5 of the output tubes. Instead of 0.8V, they were all between 0.35 and 0.4 volts. The sound was beautiful on my test speakers, no power supply noise even after an hour playing. Voltages after an hour were essentially the same as the first full voltage readings. How is it possible that this amp plays as is, without having to replace the Power Supply caps or the other electrolytics on the board? How are 50 year old electros NOT dried up and humming/buzzing? Are they just time bombs?