Need more bass response

You may effect some drastic changes just by playing with the placement of your speakers. Isolation feet can have a big effect on the components, and certainly the acoustics of the room is a huge factor.

Since you have not spoken about any of these issues, you might lay them out for us Audiogoners to consider before making equipment suggestions.

Ax you really need to experiment with cabling & tweaks; I didn't used to believe in this either until I tried it. Bottom line: you really don't know what your existing equipment is capable of until you find the right cables & tweaks to make it sing. Get better components & then choke them through your same cables & you'll continue to experience unsatisfactory results.
You need to experiment with upgrade AC cords (no two sound the same so be prepared to try different cords on different components) also experiment with interconnects & speaker cable. Then move on to shelving, pods, cones, footers, etc.

Regarding the need for more gain: I don't understand what you're seeking without further explanation? You want more power; then a larger amp is in order?

Hi, Axspike. Don't be so modest, you have great gear! I recently gained bass response and impact by changing the tubes in my Blue Circle preamp and upgrading my entire cable set to Virtual Dynamics. This weekend I swapped in an NOS pair of VT-231s to replace some 6SN7 GTBs and got bigger, more extended bass. I was quite surprised. If you're using stock power cords, the Virtual Dynamics cords will definitely be a big improvement in all areas, not just in the bass. Funny thing is is that I wasn't even looking to improve bass, I was trying to improve other areas of my playback, and the bass got better as a byproduct.