Thus far I have decided that the sound I like best is running that titty wide open on volume and bass with the switch down (on or off) and the treble on 6 or 7 with contour around 4. D.M.N. how to I test whether tubes are still good? I'd still like to replace to something matched. Currently has two different kinds of 6550s. I feel like the consensus is to go with JJs but I'm open to suggestions.
Guitards seemed apprehensive about me micing. Thought I was loud enough. But they both rehearse with a single 412 and JCM2000. Loud rigs are 4 412s and 4 JCM2000s and small stage are full stacks so I doubt that would work. I'm assuming your 2x215 2000s rigs use 8 ohm 215?
Well, if they sound good, then I'd run them till they give out. I have the original set of US Tung Sols in one of my Sunns, though they're starting to give me some unwanted noise, and I should replace them soon. Are they not all RCAs in yours? The other thing to remember is that honestly, if the tubes can bias up properly, there isn't necessarily a reason to have a matched set, often they didn't back in the day (just throw in and bias up whatever was around when a tube went south). I had a pair of RCAs and GTs in my 1200s, and it was totally fine for a long time, I only replaced them when one of the GTs was starting to go microphonic and I had the amp serviced (it now sports current production Svets). I can totally appreciate wanting a matched set though, it's something I prefer as well.
I've heard solid things about the JJs, people seem to really like them (and I believe Conrad recommends them as well). For 6550s, I've also heard good things about the current production Tung Sols from New Sensor. I've been looking at maybe going the KT88 route at some point and splurging on a set of Gold Lions, but recently I've also been looking at the Valve Art KT88/KT100. I believe both JohnK_10 and Edbass, both who have had years of experience not only with tube amps, but with Sunns specifically, recommend them as great tubes, and also in expensive. They're Chinese made, but apparently modeled after the GEC Genelex KT88s, and it seems guys in the audiophile world really dig them for their clarity. They're also like...$29 a tube, so I think I'll just go with them, see how they sound.
My 2x15s are a little bit odd. I've only ever been able to source 8 ohm JBLs, meaning my cabs would either need to wire to 4 or 16 ohms. To get the 8 ohm cab, I'd need either 16 or 4 ohm JBLs, which I simply haven't found. Thus, with one cab I use the 4 ohm extension on my Sunn (this is totally fine, the Sunns work on total load, not needing a load in the 8 tap to use the second tap, etc). To use two is where it gets a little tricky. What I do is use a Series-Parallel box, which I wired up myself using and old pedal. I'll see if I can find the plans again. Basically, what it does is you plug two four ohm cabs into it, and it runs the cabinets in series, meaning they add up to a total value of 8 ohms. You then plug a cable from this box into the 8 ohm tap on the Sunn, and everything runs hunky dory.