the best amp to run the bass of infinity RS-1b's

I have a pair of infinity rs 1b's and am running them with a pair of bryston 4b-st's. I have a nakamichi dragon 3 piece cd setup with a nakamichi CA7A pre-amp to the brystons. I have 2 pairs of mit MH-750 CVTerminator II cables to the speakers. I am looking at a pair of Bryston 7b's at 500/ch at 8ohms, 800/ch at 4ohms. Classe Ca-400 400/ch at 8ohms, 800/ch at 4ohms. Mcintosh mc2500 500/ch at 8ohms. Perreaux 5150b at 500/ch 8ohms. I like rock,jazz country and classical. All the amps are for sale in my area and I am wondering which would give me the best punch and sound for the type of music i listen to.

Thanks for the help
Thanks.  The rest of it is CJ 14 and 15, MR-78 tuner, and an old Philips CD-80.  The CD player will be the upgrade after the bass amps are replaced.  If you hear of any IRS-V's for sale, I'd like to know.

I had the Adcom GFA-565's rebuilt 3 yrs ago by a place called Big Sky Audio, Rick Krzemien.  He replaced all the caps.  We've agreed I'll send them back and he'll look them over.  I'd like to fix them, and send them elsewhere as usable monoblocks.  I won't have them back in my system.  I don't expect they have a lot of value, and I don't expect to make much money here, but I also don't want to just take them to the junkyard.  They're cosmetically perfect.

I've looked at the Perreaux Prisma 750.  As Dave said above, I believe one needs an amp that "doubles down".  The Perreaux seems to be a good candidate in that respect.  I'm also looking for an amp that offers DC output protection, and that would include the Classe, Perreaux, and Spectral, and perhaps others that I don't know about yet.  

Although the Perreaux seems to nominally fill the bill, I'm reluctant for a couple of reasons.  First, they don't have much presence in the USA.  Second, I need some amps that will work well with speakers I might buy in the future.  I tend to favor established brands, even at the sacrifice of perhaps some ultimate audio quality, in the hope that 10 years or so down the line such amps would have some value, and also could be repaired if necessary.

It's been so many years since I was intimately conversant with the requirements of the Betas, but are the woofer towers the ones whose impedance drops very low, and require the current levels that these "welder amps" such as Perreaux offer?

Thanks for your input.

5,368 posts
01-20-2017 9:12am
You do have an incredible system- melbguy1

Happy Listening!
Cheers Jafant!
Still looking for bass amps for Betas, but have narrowed down the field.  

Have rejected Spectral, because you cannot connect them to anybody else's preamp, and they won't warranty them with the Infinity crossover in between a preamp and their amp.  Although these amps have a fine reputation, the company is rather difficult to deal with.  Just not worth it.

Have rejected Classe, because of their recent corporate issues--are they out of business or not?

Bryston 7B's on the list.  Cleeds mentions the 4B's, but these are getting a bit old now.  Would the 7B's be a more modern equivalent?

Ayre MX-R 20's on the list.  From all I've learned, they make a fine product.  Going to Colorado soon to audition them.

PS Audio M700's on the list.  dlcockrum mentions that the better Class D amps would work fine.  Is there a particular reason Class D would work well on these woofer towers?  The PS Audio M700 offers a lot for the money.

Texas25 mentions the Crown, which is a good candidate.  Do you need the damping factor on the servo-controlled bass?  How have these worked out? 

Thanks for the help and suggestions.
An Electron Kinetics Eagle 2 (A, B, C, or D version) can be had for around $500. A great amp for woofers. Yeah, it's an old design, but so are the Quad ESL and Magneplanar.