Well I did buy 4 KT88 and installed two of them on the left chanel of each amp. I use one amp for the left speaker and one for the right. Then I use the left channel of each amp for the bass/highs and the right channel of each amp has the EL34's and they drive the Mids. The result is good. I think the speakers have a little better bass kick to them. I built the crossovers myself. The woofers are 18" with an SPL of 97db with 1watt. The mid horn is a Selinium 405 Ti driver with a big JBL lense and the high's are Crites horn tweeters. The mids and tweeters are rated @ [email protected]
So to balance out the drivers I have added volume controlls to the mid and Tweeter crossovers. My cross over points are 800hz/8000hz. I don't think using the kt88 made a huge difference in the bass, maybe it's more like a tweek. When I was building the cross overs, I swaped out Janzen caps for Audyn caps, that was a night and day difference. The Audyn caps were much more open and life like sounding, a real improvement in the music.I think the type of tube your use is a matter of taste, a small pinch of taste. Speakers and source points will make the largest difference in a system.