Re: SF Pro Reverb to Blackface. Recommended?
One of the most overlooked parts of Bf'ing is the lead dress. Especially the tube heaters. A lot of people prefer the SF's over the BF's for cleaner tones though.
But for me the BF's sounded better and it's worth it to BF an amp. But do it right. My late 70's Torres hacked SFDR was done by someone a few years ago and I never really liked it that much, it was better with a Mercury magnetic PT though. I have been learning more and more about amps since I have been building my own.
I went back to the DR and found it was not totally BF'd. He had not changed the B+ resistors. It still had the 2200 and 10K, that's 230 volts on the preamp plates!!!!!!!.....I put 2-10K resistors as per the schematic and now I have 190 volts....it not only sounds a million times better but so does the reverb and tremolo....it's like a new amp.
I also swapped some resistors that had drifted and used a mix of old caps, silver mica, Mallory 150's and orange drops depending on the part of the amp.
I also cleaned up the lead dress and re-twisted the heater wires tight. Made sure it was grounded correctly too. It sounds great with an old Jensen C12N and it's much less noisy.
So just get a BF schematic and make sure it was done correctly, also check the voltages and for drifted resistors. And always change really old electrolytics.
