Amp recommendations: Wanted, Bass and Dynamics

your passive preamp situation is part of the problem. try an active preamp first.

The reason you are lacking dynamics and punch is probably your preamplifiers fault. Passive preamps (especially ones that are not state-of-the-art) many times limit dynamics and resolution and bass and trebble response (one can also run into impedance matching issues with passive). I have owned many passives, and I strongly feel that in most instances, passive preamps are not the way to go.

What amp do you have now?

I would consider upgrading your preamp before your amp (unless you have already sold your amp....).

The amps you list above run the gamut of what amps sound like. If you are looking for punch, I do not think the Monarchy amps fit the bill. I have had them. I like them a lot. But lower end control is not one of their strong suits. I have never had the Marsh, MF A3CR, or Rega. But of those I would look at the Musical Fidelity amp. MF makes very good reasonably priced gear.

Either Bel Canto, PS Audio, or Krell will probably get you more punch than the amps above. I am not sure how the old Krell amp would hold up to the much newer Bel Canto and PS Audio amps. One thing about the Bel Canto is that it is POWERFUL especially when used as a monoblock. The PS Audio has gotten a lot of good press, but I have not heard it. Although the PS Audio and Bel Canto are both switched amps (Class T digital amps), I have heard that they sound remarkably different. You might want to read the Stereophile review of the PS Audio amp to get some idea of how it sounds.

One comment about Krell.... That KSA 150 amps gets really hot. I think one could use it for a grill with the right setup. Remember that heat really determines the life of an amp (or just about anything to one degree or another). The hotter an amp gets, the less lifespan it has. The 150 was new about 10+ years ago if I remember correctly. Getting an amp like this that runs really hot that is 10 years old, you may have problems with it in the near future. The Bel Canto and the PS Audio HCA amp (I am pretty sure) in contrast run cold.

KF

With a passive preamp you should be looking for an amp
with an input sensitivity under 1 volt. Like Tok2000, I use
a Gamut D200, and a passive preamp with the D200 set at it's .775 volt input sensitivity, with 5 meters of interconnect cable between the preamp & amp. Having just tried a active preamp for comparisons, there's no lack of dynamics, resolution, bass or treble response. If you can
up your budget, suggest you consider a Gamut amp, there are a few currently listed on Audiogon.

The MF A3CR is a great amp, but not a bass monster. I own one, and regardless of how much I love it would suggest something else if you want serious punch. As for the Monarchy amps, they sound lovely, but transformer hum can be very noticeable in these units, regardless of what C.C. claims. I've gone this route as well, and hated to part with them (they really did sound great), but they were just plain noisy.

I know that passive pre's have a reputation for lack of extremes, but without getting too deep into the philosophies of why on earth we should accept that an active "gain" stage is needed to primarily Reduce the signal, I would like to expect that the source components, amp and speakers should all work together as the cables and preamp become utterly invisible.

The Spendors and Music Hall pieces are smooth and musical. Now I need an amp with enough speed and punch to make them come alive.

I'm coming off of a multi-channel McIntosh to concentrate on my new 2-channel system.

Thanks for the help thus far!