Tube Saturday.
Just had my AD200B’s gone through and did a big tube swap in both.
One, a 2011 model, which I got about a month ago for just $700, needed the power transformer taps changed as it was a UK/EU model, with no 120 VAC option on the switch, only 220/230. Now it’s only 120, and the switch is disconnected. Also had a “Power Amp In” setup and put in where the “Active” input jack is located. With all the fancy pedal pre-amps, this allows me to play around with these. For example, I have the Ampeg SGT-DI pedal, which has a B15/SVT setting and cabsim switch with 115/410/810 setting, and a preamp out jack. Now it goes right into the power amp in and I get a 200w B15 or SVT!
This one had JJ 6550’s and “PM” 12AX7’s and a 12AT7 (UK branded Chinese tubes I believe). Now it has a matched set of Sylvania 6550’s (Phillips labeled), an RCA 12BH7 in place of the 12AT7, and two RCA “long black plate” 12ax7’s
2011 model:
And in my other AD200B, a set of GE6550’s and a GE 12BH7 in place of the 12AT7. With (for now) some good JJ 12ax7’s under the covers:
So the way I do this is, one of these stays at the rehearsal space with an OBC115, and gets regular, once a week (at most) use. The other is parked at home with an OBC115 and OBC210 cab. When the band has a show, I load up the amp that’s at home, and either one or both of the cabinets. Then after the show, at the next practice, I swap heads and the one that was parked at home and just used at a show will get regular use at the studio. Also nice to not have to go to the rehearsal space and bring an amp and cabs down stairs on a gig night.
It will be interesting to see if I notice a big difference between these heads.
The one with (now) the GE’s is the one I have had for awhile, and it had “PM” 6550’s in it. My tech did a good “cook and burn” test on them when I got it and they checked out strong. When he put the GE’s in yesterday, he had to bias them up quite a bit from where it was with the PM’s, but he got it putting out a solid 169 clean watts. Since no other changes were made, and this was the amp I used at rehearsal on Thursday, I’ll bring this back to the space on Monday and see if I hear a big change.
I probably won’t, but I’m sure I’ll convince myself that it sounds even more awesome with good old USA power tubes!
