V1 tube thoughts?

All about tube choices for the JVM series. See workbench for biasing and tube problems you may have.

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corvairdoug
Pub Band
Posts: 74
Joined: Sun Jun 05, 2011 8:44 pm

V1 tube thoughts?

Post by corvairdoug » Wed Oct 30, 2019 12:20 am

I heard today of a guy swapping a 12ax7 out and put a 12at7 in its place. Or, a 5751? You guys ever do this, and how did it affect your amp?
Seems like I really like OD1 orange gain amount, but sometimes the hum and noise is intolerable. What do ya think?
78 LP Deluxe Goldtop; 79 Strat; 98 Korina Epi Explorer; 11 EPi LP; late 80's Seagull 12; JVM 410H with Choke mod & Anti Stiffness mod; Home built cab w G12T-75s & Vintage 30s

okgb
Club Circuit
Posts: 627
Joined: Fri Apr 29, 2011 1:50 pm
Location: The Great White North-Winnipeg

Re: V1 tube thoughts?

Post by okgb » Fri Nov 01, 2019 6:13 pm

More gain = more noise , generally speaking. there are gain reduction mods in the bible, but
12at7 has a gain factor of 50 compared to 100 with the 12ax7, the 5751 is 80 , so I'd start there.
I have a fender super sonic, that replacing the first 12ax7 with a 5751 solved the noise [ waterfall ] issues & sounds better
Amps JVM 410H [too many mods to mention ] '73 50w lead, 70's vibrochamp , mesa mkIII U.S. Vox pacemaker
Rock , pop rock & Blues style's mainly played
Gtr's Musicanman " Luke " wolfgang [ carved top w pearly gates ] Hondo lazer , Warmoth strat
Fx t.c. 2290 , Lexicon tc verb
Pedals tbone plexi , t.c. chorus , various handmade & usual suspects t.s. , zen , CB wah ..........

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