EL34 upgrade

The best EL34 is Yugo 6CA7 fat bottles. I used to purchase them $8/piece from ebay almost 10 years ago.

The price on Gold Lion reissue KT 77 quads was $180, plus tax and shipping, when I bought mine. They were a substantial improvement on the Groove Tube Mullard EL 34 reissues I had bought previously. I've used EH EL34's and Winged "C". The Mullards and Gold Lions were better.

If you want to go up to the Shuguang Treasures, they are quite a bit more expensive (you probably already know this). I would contact Brent Jesse or Andy at Antique Sound Labs, they are in the know, and will treat you right. Jim McShane is good also.

Regards,
Dan

I have really enjoyed the New Sensor mullards in my Primaluna PL2

The Winged C is a good choice and a definite upgrade from the three you've already tried. The Gold Lions are great tubes, but make sure they're compatible. KT-77's, KT-66's, and some 6CA7's are 7-pin tubes (originally 6CA7 was the American designation for the EL34, but a true separate tube was eventually developed as another beam tetrode). I really like the GL reissues, but I have one ST-70 that works fine with them and another modified one that's not compatible. Both the KT-77's and 66's are worth a shot.

The Shuguang Treasure 6CA7-Z's are even better, but they'll really set you back. I'm currently using these, and I even think they sound better than some of the NOS tubes I have or have used, but they'll pretty much set you back more than anything other than the really heavy hitter NOS tubes (Mullards, original Genalex, etc.).

I would strongly suggest NOS Siemens. Upscale Audio has them for $220 a quad, but you can find them for less. I actually have three quads of these that I'm not currently using if you'd like to try them.

Out of all the options and your stated price point, I'd suggest either the Gold Lions or the Siemens.