That amp in particular is very easy to change to 230V. There is a plug/socket affair on the back so you just pull out plug and move it so that the arrow points at 230V. Some of the Stax amps are like this while others require you to move some wires around or solder in some jumper wires. Both are easy once you know how they should be configured.
One has to be quick to snap up a SR-Lambda these days so that has to be taken into account. I'm with Deepak though, the Lambda Pro isn't bad by any means but the older SR-Lambda is very special.
I did something truly nuts tonight, listened to the BHSE at max volume (from a 2V source) just to see what would happen. What I listened to was the beginning drum solo of Megadeth - Trust with the SR-007 Mk1. It was more then enough to make the Omegas start to vibrate but both headphones and amp held up perfectly. Now we are pretty far away from the imminent destruction territory for the Pro bias sets here (+/-600V rails would land us there) but still this was very loud indeed.
How much power the O2's need isn't really that straight forward. More power is always better but they also seem to "like" certain amplifier traits more then others which is why the small SS amps work better then the Stax tube amps even though the latter has more power.
The later BH has one 10M90 per tube instead of the six 2SA1968's.
I'd say this could have been a source issue since the KGSS is a lot more powerful than any ES-1/2 ever built. That damn 100+V offset just kills the amp...
The LCD-2 thread was a nice place for a while last week when chief dumbass wasn't hanging around. He really takes the art of being a fucktard to a new level...
I finally plugged in the SR-007 and man those new Mullard's are just awful. Not only are they noisy as hell (snap, crackle and pop when I turn off the amp and sing when I turn it on) but I first thought the amp was broken, it was that bad. Swap in some XF2's and this is more like it...