best amp for BASS

Bass response is HIGHLY dependent the on the room and where the speakers are placed in the room . What you perceive as an amp issue might be resolved by repositioning the speakers or room treatments. Throwing money at the problem by buying better equipment will only take you so far. Since money does seem to be a major concern, you may wish to seek professional advice on room treatments and speaker placement.

If you like YBA, Krell may not be quite what you expect although it does have tight bass (the 600s on Wilson Sophias). FWIW, I had a Krell KSA 100 for a while and it was good but a little bright.

I liked the McIntosh MC1201 monoblocks the best however, slamming massive McIntosh XRT28 speakers like I have never heard before. Everything was shaking except for the amps and speakers (they weigh incredible amounts). I was impressed but it's a conservativly-rated 1200W per channel amp afterall. At any rate, try to audition whatever you can because room and system synergy are critical for any new component to sound good. Arthur

What great advice!Put the money back in your wallet and take a good look around.What you probably need to do is start to "see" the sound with a rat shack meter and a test disc.Or better yet a signal generator.You mentioned the bass was not up to par, is it weak ? Do the subs max out and make a mechanical distress sound ? How are the four twelves wired ? Do they have an 8ohm load (which would lead me to believe they are series -parallel.Not that Krell amps are not the answer some day, always look further to correct the problem.Sounds like a great system and a whomping big room.Amost willing to suggest old JBL scoops from the pro audio world for that big ol' room of yours.I just built some subs using Adire Tumults with some Adcom 555mkII's and they fit the bill.You may need a parameteric eq to remove room modes and really start to hear the bass.Good luck and post your solution.

Try the Crown K-2, maybe two K2's in bridged mode. Although it's cheap I expect that it will outperform a Krell 600 or 650.
I use a Crown K-2 for my Wilson Audio WHOW sub which complements my Watt/Puppy 5.1. It has fantastic control and power. As the WHOW is a mono sub I use the K2 in bridged mode. It has 1600 Watt @ 8 ohms (2500Watt@4Ohms). Damping factor is above 3000!
List price of a Crown K2 is about 1800$ only.
Use XLR connections with the K2 if possible!

Geez,I'd love to have a Krell for Mains let alone for using one just as a Bass Amp.

I always thought Bass was the easiest single driver to drive provided you have a high Watt capability along with good Damping Charctheristics.

Just thought Krell might be alittle of overkill for a Bass amp.

How about an older MUSE or as someone aluded to the McCormick's. Anyways,just thinking!