In building some dual, choke input, power supplies I ran into some more hum. I have pulled it down with various cap positions and size. Someone suggested raising the cathode heater of the 12au7 (6sn7) above the 165 volts it is sitting at.
I know the Coronet riaa is tied to more than meets the eye (according to Jim). Any Problems with say injecting 200volts to raise it 35 over the 165v cathode. And while I am at it some people say raise them all 30 volts. Any problems with doing it to the first two tubes.
In defense of the orginal design it was the most stable, silent, phono pre I have ever built. This was in point to point and not the perfect layout. I have built many phono stages that just did not work period and others that where as stable as the middle east. This saids alot about this design.
Thanks Tom
