schundog Posted April 30, 2011 Posted April 30, 2011 OK, finally got a chance to check out the distorted BJ. I think the problem was loose tubes. A couple were not seated tightly in their respective sockets, probably from my last speaker swap. Could that have caused the lack of cleans?? None of the tubes looked bad, burned or damaged. They all glowed nicely and had no loose filaments. (That is ALL I know to look for with tubes/valves!) They are a matched set of JJ's, so unless one is obviously damaged I'd like to keep them in there warming up the amp innards and my tone. Anyway, the BJ sounds better now. The cleans have come back unless I push the Master and Volume knobs past their usual clean zones. The Bill M mod project will have to wait. Just scored a nice Hermida Zen Drive pedal to put in front of this sweet little amp. Git, You have got some GORGEOUS amps and guitars!
Gitfiddler Posted April 30, 2011 Author Posted April 30, 2011 Git, You have got some GORGEOUS amps and guitars! Thanks, Brian. Your gear ain't nothin' to sneeze at either.
schundog Posted April 30, 2011 Posted April 30, 2011 Another tip from good ol' BillM is how to retension your tube sockets if you have loose tubes. Here's the link. http://billmaudio.com/wp/?page_id=171
Hfan Posted April 30, 2011 Posted April 30, 2011 Hfan, no, in fact, I think the transformer HELPED the headroom, if anything. As BillM did my mods, he modded it with a trim pot that adusts the power tubes bias for longer, cooler, better-toned operation. I played it tonight through a Gibson Faded Flying V with Gibson pickups, a Heritage 170 w/ Schallers, and a MIM Jimmie Vaughan Strat. All sounded good and clean at pretty loud volumes, obviously without the "Fat" switch engaged. I don't know exactly WHAT did WHAT, as he did all of the mods at once, and then I changed the speaker relatively shortly thereafter to the Eminence Texas Heat. The only problem, if you see it that way, is I could NEVER come close to recouping my cost of modding this amp, so I guess it's with me for the long haul, which is OK by me. It is cool, you had the master do the work himself. He is in my neck of the woods and I could have left mine with him with no shipping, though he had a large backlog at the time. I'm a tinkerer and kind of did mine one or two at a time over several years. Only problem with that is with each disassembly the ribbon cables get stressed from bending them when removing the PWA. I wound up busting 1 or 2 ribbon connections then tried to restrip and resolder the ribbons, eventually went to straight wire which can be individually moved for noise / oscillation problems. Good thing was seeing how each mod changed things. I ordered a new set of pwr tubes (I decided to try Mullard re issues, I have JJs currently) will play around with pwr tubes and re biasing as time allows. Bill has two different bias points recommended in his various documentation, he recommended what was on the instructions with the new x former. Also got some new EH 12ax7's just to have some spares around. To be honest I don't mind the early breakup, it sounds awesome and I have an old Twin for lots of cleans. I may just pick up a speaker.. probably an Eminence for budget reasons, may look at Celestions The Texas heat you installed is on my list of potentials as well.
Hfan Posted April 30, 2011 Posted April 30, 2011 Another tip from good ol' BillM is how to retension your tube sockets if you have loose tubes. Here's the link. http://billmaudio.com/wp/?page_id=171 Re the tube sockets, besides retensioning the pin holes, I also spray the pins with de oxit. Seems to help especially with older tubes. Poor connections can cause all kinds of problems depending on which tube and which pins are poorly connected to the circuit.
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