Found it

[isaac]

I always like Winged C's. But it sure does help when the results are like yours. That sounds great! You should test the two sets when the amp is really cranking, because of course, that's when you hear power tube differences most of the time.

[isaac]

Oh and one more thing with that, you might find you like the svet's better now, just because when it's cranking you might get a little tighter bass, and more projection. That's the thing with the voltages, two high, kinda makes it brighter and more forward, and low can get almost mushy, of course then it has to do with power tube sag, when it's really cranking also. But in general, that's one thing to point out.

[daz]

Thats true, and the svets are definately more solid in the lows. The C's tend to mush out the lows even at low volumes and as i get higher they just seem inarticulate even tho the overall tone would get harder and brighter, if that makes any sense. I really can't test it much at high volumes tho, and at this point i doubt i'll ever do another gig. So i really don't see myself needing to play it loud. However, I want it so sound right when cranked whether or not i gig ever again just because I want the amp to be right. In any case the svets are now in contention with the C's when before this change in the power rail it's wasn't even close. Funny how that works....you see people at forums arguing about so many things that might sound completely different to them if they changed one small thing in thier guitar or amp or anything in the chain ! I would make a change in my amp only to find the treble bleed in my guitar now needs a different value of cap or resistor ! So you see people arguing about whether a treble bleed in a guitar is good or not, yet thier opinions might do a 180 with a small change elsewhere.

[isaac]

Did you make sure that you have the amp biased correctly for both sets of tubes? That will make a big difference between two sets. Just a thought.

[daz]

Did you make sure that you have the amp biased correctly for both sets of tubes? That will make a big difference between two sets. Just a thought.

Absolutly. I even have a dual bias setup so it even eliminates any differences if one set is balanced much different than the other.

[Gingertube]

The 12AX7 does not like low anode voltages - it responds to low anode voltage with lots of grid current which usually results in a slew of high order harmonic distortion products, high order (particularly the odd ones) being the sonically objectionable ones.
If your bias point / B+ rail is such that that anode voltage is less than say +160V then it needs a circuit change to get this voltage UP.

I like to run the anode at >200V

Cheers,
Ian