Bass is not enough !!! Speaker problem? Speaker cable? Power Amp? PC of Power Amp?

Source? Recording(s)? How old is your speakers? Did they play at least 50hours?

Like the last two posts, I agree that it may be your source. The amp, cables and speakers can only reproduce what is sent through and to them. I had the biggest improvement in bass response going from a CD player to a SACD player (better built, more substantial power supply, etc.) It got even better when I got the matching integrated.

Better ICs tightened up and toned the bass while allowing better delineation and nuance. Some new monitors took it big step further by being able to portray that new bass presentation, and better speaker cables took it further by sorting out the gestalt of it all. But it all started out with that SACD player, so make sure your source is up to snuff.

All the best,
Nonoise

I feel it's not the room that is the most important, but how the air volume of the room and your ears are pressurized by the speakers. Speaker placement is everything. I invite you to see my website - myspeakersetup.com, read ALL the articles, then contact me for the true answer to your difficulties. You can have the best gear available, but if the speakers aren't where they BELONG, you have no chance.

I second the questions about what source(s) you are using. In particular because the rather low 10 Kohm input impedance that is specified for your preamp will definitely roll off the deep bass if driven by the many tube-based source components (and perhaps also some solid state components) which have output coupling capacitors that have been chosen with the expectation that preamps having higher input impedances will be used.

Regards,
-- Al

How far is the speaker from the front wall?   Moving them closer might help the bass.