tubes in a Copland 504???

I know there are 4 6550,s ( btw can I use KT-88,s) But not sure on the rest. Looks like 4 12au7,s and 1 12ax7 as a pre tube. Please help me out. I just got the amp and am looking to upgrade the tubes.

jayb7710-06-2010 4:33pm

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jayb77 OP Details Discussions Posts This discussion Message User 46 posts 10-06-2010 at 07:08pm Copy Comment URL Report Comment Edit Delete CAN you use KT-88,s??? Please thats the main concern now.
mechans Details Discussions Posts This discussion Message User 3,048 posts 10-06-2010 at 11:49pm Copy Comment URL Report Comment Edit Delete Yes you can use KT-88s, but you may need to adjust the bias to get the most out of them and not burn them out too quickly.
jayb77 OP Details Discussions Posts This discussion Message User 46 posts 10-10-2010 at 05:13pm Copy Comment URL Report Comment Edit Delete OK How do you adjust the bias? I am assuming its the little blue and white pots in front of each tube but as I said assume. Help if you can.Thanks

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