Name: Ed
Email: goforthsound@yahoo.com
Subject: Music Man 65 Head Bright Switch
Thread: 45
Time: Thu, 7 Mar 2002 10:47:23 UTC
Hi Kenneth, first off how is the condition of the tubes? They may need a change or the power tubes might need rebiasing. Does it have the stock speakers? Is the guitar cord a low capacitance type? The 12ax7 is the driver to the powertubes (6CA7 power tubes usually in the older models), when these get old the sound usually gets dull. I used to have a HD130 212 with the 12ax7 driver tube and 6ca7's. As far as the bright switch, the schematic shows a .01 or .015 bright cap. If its mounted on the switch, you could try a different value so it won't be as bright when on. Try a .0047uf, .0022uf or .001uf. The lower the value, the less bright (.0047uf is about 1/2 half as bright as a .01uf). And when the switch is off and you would like a slight bit more brightness, try putting a 500pf or a .001uf across the volume pots middle lug and the lug closest the input jack side (left of the middle lug)of the pot that is not going to ground. this will give the amp a bit more sparkle when the bright switch is off. You may need to experiment getting the right combination, since guitar pickups are so different in tone. This is one way how you can taylor the amp to your guitar. :) I hope this helps, if not email me... THere is a slight difference in tone when using ceramic caps instead of the poly types might be in there. I like ceramic in some amps, they are a bit more organic in tone, where polypropylene or polyester might sound more articulate, and silver mica is very pure, quiet but sometimes harsh when used with distortion. Pick a cap that sounds best, so get a couple of each if your into fine tuning... :)
regards,
Ed Goforth