no low end st70

You might also make sure that your speakers are in phase. IOW, that the 'plus' from the amplifier is going to the 'plus' on the speakers **in both channels**.

I think Trelja pretty much hits all of the points. Especially the power issues and the impedence matching ones as well. If your amp is biased properly (and this is very important) and you still have poor bass response, you may have to just consider getting either more suitible speakers or a different amp. I've had more success in the bass department as well as FR linearity, using amps utilizing the 6550/KT88/KT90 family of tubes.

Atmasphere (Ralph) raises a good point. Certainly worth checking this out. Years ago, I had a pair of speakers (Rectilinear III's) that came from the factory wired out of phase! In checking the phase, if it seems correct, try reversing polarity of only one of the speakers just for the heck of it and see what happens (just in case the speakers are incorrectly internally wired).