Hi David,
I run my 6550's at around 50mA at 450V screen voltage in push pull. Sovtek 6550 BTW cos they sound soo good that I left my GE 6550s in their boxes for now. I also use a strat, L series with low imp pickups (5-6k) and one or two Marshall 4x12 '68 with G12M orig lead conus.
I must say I like the 2x12 EVM12L way better with these tubes. The Greenbacks can not handle the lows that I like from these tubes unless I decrease the .1uF PI outputcaps to .022 or even to .01 against 220K bias resistors but then the lows are gone....but with the EVM's I can use a .1uF and be happy with it.
I can believe that! Even vintage Greenbacks have to have a spikey frequency response compared to EVs, and they do dump the bass, like a lot of Celestion designs.
6550s are inherently pretty linear response tubes, so I can see the bass coming thru better with EVs.
I have .047/100K on my 6550s, the classic Hiwatt combination, but with a 5k6 OT, not 3k4, so I'm not running 70W, probably nearer 40W as my ears don't hurt yet! (My ears are -25dB @ 8kHz anyway, had 'em tested last year, so I'm probably safe).
This has been (still is) an ongoing experiment for me. I should probably get my own 4x12 half stack out of my landlord's recording studio (same building I have my shop in) and see how that sounds too. Built it myself with two Eminence Private Jacks and two Celestion G12 Blues, 12 ga. wire. What do EV 12Ls go for these days?
