So far, I've played around with jj83, mullard, Tung-sol and Jan-71's in Randall rm100.. All my tests are for a blackface module trying to get warm and clean sound.
JJ83 - sound good and round in general, but for detailed work often get to mushy quickly. Having 1 in a v1 wasn't too bad
Jan5171's - PI position sounded good just like everyone recommended. Didn't sound bad in the v1.
Tung-Sol - tried for clean sound I like using one in the preamp and one in the input. Sounded great in the input - made everything loud and present - clear and detail and good bass, but didn't like using two tung-sol's sound's too 'hard'. Summary - for clean sound needs to be supplemented with another softer sounding tube.
mullard - I liked this in the input - it gives a soft tone to everything but alot quieter than tung-sol. Didn't like it for hi-gain though.
summary - I have found two setups I like, they're both decent but I'm still not entirely satisfied
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setup 1 - input - mullard - blackface v1 tung-sol, v2 jj83
setup 2- input tung-sol - blackface v1 5171 2 jj83
don't quote me
