Hi! Few days ago i purchased 1962 Scott 299C amp. I like it a lot, it realy shines after all modern amps I have had. I wasn't very lucky: my amp nees some restoration. First, There is a 50 Hz hum coming out of right speaker. Sometimes it disappears, but it comes back after a while. I swapped tubes L <-> R. Hum is there.. I don't know what to do with that, so I'm going to do full recap and try another 12ax7s. Second, I measured voltage on pin 6 of 9175. It was -16 V (schematic says it should be -18.5 V). Also there is only 300 V on pins 3 and 275 V on pins 8 (should be 420 and 410 V). I found that power transformer doesn't supply proper voltage to rectifier tube: 600 V before rectifier, and 300 V after. I use 220V-110V transformer to power my amp for my local voltage is 220 V. It/s 2 kWt Could the voltage SAG be the reason of low voltages in the amp? Third. Pity but my amp has no bias pots. It has fixed bias. That's what Scott's site says: "Only a handful of vintage H.H. Scott amplifiers employ Fixed Bias that is truly fixed. By that we mean there's not a Bias Control potentiometer to be found! Such models include: Types 208, 222-C, 299-C, 296, and 340 receiver. Assuming everything else is healthy, you're good to go." What if I change tubes? Shouldn't I do bias adjustment after that? Thanks for any help. I am new in this.