EL34's, which are true pentodes, have very high voltage capabilities (800 vp and vs), but their current output is still relatively low. You CAN get an honest 100 watts out of a pair, but they'll be VERY unstable. That's where the "KT" tubes and the other beam tetrodes (6V6, 6L6, 6550) have an advantage for bass- better peak current- which means better, beefier bottom and more punch, what most folks associate with GOOD solid state amps and subwoofers. The Peavey VB-2 uses six EL34's to get its 225 watts. Its advantage is having an EXCELLENT s/s preamp so you don't really notice less punch down low until you really start pushing it. Vintage Hiwatt 201's, at least from what I've seen, were made with KT88's over EL34's at a ratio of about 5 to 1. I suspect the EL34-equipped models were early production.
