Hi Myles!
Newbie alert! I have recently purchased a Rivera K-Tre 55-watt combo purely on the basis of the spectacular clean channel. When I got the amp home, I discovered it actually had a dirty channel too -- one for which I hold no particular love. I've tried a number of things with greater or lesser success:
- I returned the combo to a near-original tube setup (12AX7WBs across the board), and the clean was great, but the dirt was staccato as opposed to smooth
-I replaced the tubes with 12AX7EHs across the board, and the whole thing went dark
-I put back the 12AX7WBs and added a 12AX7EH in position 1. It all got better, but I still find it a bit staccato-sounding
For what it's worth, my other rig is driven by a JMP-1 in which the dirty preamp is run through a 12AX7LPS. It is by far (to my ears) the smoothest gain/overdrive I've heard so far, and is more or less the quality I'm going for in the drive side of the Rivera. Alas, the LPS does not do particularly well in combos.
I'm about to order another raft of tubes (probably just in pairs for position 1 and 2) and I'm looking for advice. I'm considering Tung-Sols, JJs, and in an interesting twist, 5751s.
Anything else I might like to try?
Joe