$4000 to spend on a SS power amp - help me choose

The BAT VK-1000, VK-600 or VK-500 for about 2200. I have seen the VK-600 for 4200 but only 2 and they sold quickly. My VK-1000 made a clear difference over my proceed AMP 5.

If your $4000 budget refers to your actual budget, and not to the MSRP of the amp, then you could consider either the Ayre (already mentioned) or a pair of Bryston 7B-ST monoblocks. These two amps have somewhat different "sounds", but both offer excellent performance and are fine values.

Thanks...I'll qualify the above by saying I prefer the warm
"tube" sound over the cooler analytical sound but want some bass slam that the Graaf doesn't deliver & therefore my most recent shortlist, based on research & talking to dealers include:
1) Spectron Musician III
2) Parasound JC-1
3) Jeff Rowland M201
4) Pass Labs X250
5) 2 Belles 150A Ref or 2 McCormack DNA 2

I run unbalanced Acoustic Zen RCA's also...don't want to invest in balanced cables unless someone can convince me it's the way to go...

The McIntosh suggestion intrigues me beacause of the autoformer technology. I am considering getting the Paul
Speltz Zero Autoformer to help the Graaf deal w/ the VMPS
4 ohm impedance. The Aragon suggestion is also intiguing because of the deals one can get...plus their design.

Ultimately...I've been led to believe I need a high current,
high power amp for the VMPS.

I would not classify the Parasound JC1 as warm and "tubelike." And I have listened to it extensively in a friend's system. It is not cool and analytical either. It is about as neutral as you can get.

Given your requirement for tube-like warmth, I'd say the Rowland is probably the front-runner from your list. Timo's characterization of the JC-1 fits my experience as a dealer for that amp, so much as I like it, I don't think it would best meet your stated needs.

Other "warm sounding" high performance solid-state amps include Accuphase, Warner Imaging, and GamuT (I've owned all three, and sell the latter).

Best of luck with your amplifier quest!

Duke