I am behind on my own thread:
This last weekend I was able to spend some time (with the help of Voltron) and do some tube rolling with the Rectifiers. These were all pairs that he had, and I was pushing the L3000's only.
I started with the Standard Sovtek 5U4G that came with the amp... they are OK.
(I may not know the branding on most of these off hand)
First Roll was the 5R4GYB. Bass detail and impact went way up. The overall detail was very high, as well as the increase in soundstage. First off I was thinking that I could live with this tube.
Went to something different 6106/5Y3WGTA. These were HOT, almost sizzly in the sound. It only took a very short time to realize that these were not going to work. Soundstage collapsed.
Went to the 5R4GYA the sister to the one that I liked. It must have been a step-sister. The over all detail was pretty much there, but not as refined. The Bass weight and luster was not up to the YB version. Could live with these tubes (5R4GYA), but would be looking for the B version soon after.
Then the GZ34. Now maybe it was the pair that I tried. But these did not beat the 5R4GYB's for me in the WA5. The soundstage was not as big as the 5R's, and the detail was not up to the same level. They seem to be kind of hot like the 6106's. I think that I made a comment that they seemed to be straining (trying too hard). I listen loud, but I should not be maxing out this amp. Another indication is that I don't have to turn it as high to get the same volume level as other tubes. This was true for both the 6106 and GZ34, they got loud at a lower volume setting.
The last pair (mixmatched) was a pair of RATHEON 5U4GB's. These sounded very good. They were very close to the 5R4GYB's. They presented good detail, warmth, weight, and soundstage.
My next real step is to try the 5R4GYB's and 5U4GB's heads up. Voltron left me both pairs to try out.