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Grateful Dead Music Forum

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 #116011  by gpilcher2001
 Thu Jul 12, 2012 7:27 pm
Hi all, i'm currently back in the process of doing more upgrades to my forever on going process of upgrading my amp to Jerry spec's. The Waldo site says to use the biggest filter caps you fit in the cap can on a twin reverb. I was curious what you guys are using brand and values. While I'm a tinkerer/hobbiest of tube amps I am no engineer.

I am also getting ready to do a transformer upgrade am curious is anyone has tried the Mercury Magnetics PT, OT, & Choke? Or feedback on any other transformers would be good. Thanks Greg...
 #116014  by JonnyBoy
 Thu Jul 12, 2012 8:02 pm
Ive been told upping them to at least 500v-600 on the filter caps is plenty and the new caps are a lot smaller these days I'm sure so the size thing can be overcome. Mine are the cheaper ones like fender reissues come with but it sounds awesome anyway since I changed them.
 #116200  by gpilcher2001
 Tue Jul 17, 2012 5:09 pm
Anyone? Anyone? I understand the transformers but all you guys with the jerry mods to a twin? I found some JJ caps that are 500v 500uf that might fit. Do those values seem sufficient? Greg...
 #116201  by Smolder
 Tue Jul 17, 2012 5:27 pm
there is a good chance I will get corrected here for not following the recipe, but I've never been able to hear a difference in wither brand or voltage tolerance of filter caps. As for transformers... the PT and the choke substitution would have minimal effect on tone. The OT can make a difference. Mercury puts huge eff...

...huge effort into researching and reconstructing old transformers. Companies like Midwest magnetic Components (available via triode electronics) were doing it from the beginning. I think their lassie line for fender amps is damn good... and at very reasonable cost.

edit... sorry for the incomplete thought... on the road with poor connectivity.
Last edited by Smolder on Sat Jul 21, 2012 9:54 pm, edited 1 time in total.
 #116281  by zambiland
 Thu Jul 19, 2012 10:46 pm
Smolder wrote:there is a good chance I will get corrected here for not following the recipe, but I've never been able to hear a difference in wither brand or voltage tolerance of filter caps. As for transformers... the PT and the choke substitution would have minimal effect on tone. The OT can make a difference. Mercury puts huge eff
Ah, don't leave us hanging! I've got a pair of MM OT trannies waiting to go into a '67 Showman and a '67 Bandmaster. Just need a few spare hours to do the job. The Showman currently has a Hammond 1650T, which works pretty well, but I'm betting the MM will sound bigger and cleaner. The Bandmaster is an easy upgrade. The original OT is a piece of crap.
 #116329  by Smolder
 Sat Jul 21, 2012 9:56 pm
zambiland wrote:
Smolder wrote:there is a good chance I will get corrected here for not following the recipe, but I've never been able to hear a difference in wither brand or voltage tolerance of filter caps. As for transformers... the PT and the choke substitution would have minimal effect on tone. The OT can make a difference. Mercury puts huge eff
Ah, don't leave us hanging! I've got a pair of MM OT trannies waiting to go into a '67 Showman and a '67 Bandmaster. Just need a few spare hours to do the job. The Showman currently has a Hammond 1650T, which works pretty well, but I'm betting the MM will sound bigger and cleaner. The Bandmaster is an easy upgrade. The original OT is a piece of crap.
sorry - completed the post. The allen amps transformer for bassman is a fantastic upgrade for either the bandmaster, pro reverb, or the vibrolux reverb.