What Power amp SS would you recommend........

that has high current and lots of power for base....I will be using this amp for the bottom end (subs) of my RS 1B system. Infinity suggested (when they introduced the speakers 20 years ago) to use a high current amp with lots of power for the subs.
I am currently using a Perreux 2150B rated at 200 wpc@8 ohms and 400@ 4 ohms.
I was considering the Krell 250 KVA, Mark Levinson ML-3, Rotel 1090, Threshold Stasis 500. As you can see I am considering all used items as I would like to stau arond 1-1.5K.

Thanks all for your help!

PARASOUND HC-3500, definitely! There's 2 for sale on this site right now...
The Bryston 7B ST's do a good job on the low end. They are also Class A rated in Stereophile (for what it's worth), and they're reasonably priced.
I used a QSC MX3000a for the woofer amp on my IRS Betas. Around $1000 new, 900 W/ch. It bested Krell and Bryston in my opinion (I DID use a great tube amp for the highs).
If you can find one, an old Perreaux PMF-3150 will supply you with a very noticeable increase in bass output and control for not that much money. This is the bigger brother to the 2150 and is rated at 300 @ 8. In a direct comparison between one of my 3150's ( i have two and use them for multiple subs ) and one of my old 2150's, the 3150 was much more powerful and made the 2150 sound lean and anemic.

While the difference may be partially attributable to the increased power output, the mass majority of difference is probably related to the redesign of the power supply section. Peter did this when trying to further improve the design of the 2150 but was unable to retro-fit these changes into production for the 2150. As such, they ended up being incorporated into the 3150 series, which came out just a bit later ( along with the BIG boy 5150 ). For the record, the 3150 is of a high current design, biased quite high into a rich Class AB and also has very high rail voltages ( 90 volts as compared to most others at 45 - 70 volts ). It also runs pretty hot.

Most of the newer Perreaux designs of the same appr power rating as the 3150 are all pretty well known for having awesome bottom end. John, the owner of Chicago SpeakerWorks ( also called Van L SpeakerWorks ) recently auditioned the current 300 - 350 watter and stated that it had the tightest and most prodigious bass that he had ever experienced. It was also sucking the 20 amp circuit breakers dry : ) Art from Listener mag also commented on how warm and powerful a little two way three driver MTM array sounded when being driven by a newer Perreaux amp at an audio show.

The Parasound 3500 might also be a good candidate for the amount of money that you mention.

One thing to take into consideration is being able to match the gain characteristics between the two different amps. The Perreaux's take a little more drive than a lot of other amps, but you're probably already aware of that. Sean
parasound HCA2200, 3500, or similar, yes...volume control for easy volume match with top amp, and very very good solid bass for cheap!!(a parasound trademark really)...
In my oppinion, if you're spending more on higher end amps for your purpose, your wasting money, and not getting better bass!!!!