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
Judging from past experiences, i would consider the Classe' and Perreaux long before either of the others. A Sunfire Signature with their factory "low impedance mods" aka "Apogee mods" would also be a good candidate. These are rated at 600 wpc @ 8, 1200 @ 4, etc... Actual clipping power on mine was 780 wpc @ 8 and 1480 wpc @ 4.

As a side note, you better have a healthy AC system if you want any of these amps to work optimally. Any of them will be able to suck a 20 amp circuit dry on momentary peaks if you are standing on them at low impedances. As such, if you haven't already done so, you should get your AC system straightened out first before spending more money on something that you might not necessarily need. My guess is that you probably do need more amplifier than what you have, but assuring consistent power feed to the amps that you already have might be enough to make you think twice about needing an upgrade. Sean
Hi Darin....I have the same speakers you have! Listen to Sean...he has helped me out quite a bit! I also had Bryston 4B's but went with a Perreaux 2150B because it had a warmer sound that mated well with my set up.
The desire for a more powerful amp led me to the 3150B (Sean's suggestion) and I got it. Although I am in the mist of trying to slove a few problems (hum and funny noises), the amp is quite powerful but still retains the warmth and overall synergy with my tube amps on top.

I will watch this thread closly. Good luck

Hi there,

Oke I didn't listen to this amp myzelf(jet) but I hear great things about this amp.

The Crown Audio K2 it's 500w 8 ohm and goes all the way down

I'ts price is about 1300/1400 dollars on internet and damping factor is < 3000 Stereo Times had a great review on this amp. I'm gonna use it on the low of my IRS Beta's

It has a better slam than the Krell kma 200 ect...
This of a friend of mine that sold the Krell after listening to the K2

let me know what you gonna do.


I purchased a Pereaux 5150b, and suposibly in shipping it was damaged. I hooked every thing up and just got a buzz niose from the speakers. If I turn the pre-amp up to just about full volume the buzz would stay the same but I could just hear the music, maybe only a couple of watts of out put. So I have taken it to a shop and hope they can find the problem. I will let you guys know how things turn out.
A friend runs his RS1b's with a pair of older Krell monoblocks on the bass towers, sorry I don't remember the model, and an ARC D250 on the panels. He dispensed with the trouble prone Infinity crossover and uses a Dahlquist active crossover.

Hi Brian, I have also heard some folks doing away with the Infinity crossover. It gives me a little scare to do that although I get tempted now and then. I believe if you use another crossover (bryston, Dahlquist, Merchant) it negates the servo control on the woofers. Some say it sounds better and some say it does not. The Krell amp that a friend of mine has on his woofer towers are the 150 mono's. He retains the infinity crossover.
As to an update on my newer Perreaux that I have had it for a few is wonderful......plenty of power and control!!
Hello again

I finally got my perreaux 5150b back and hooked it up to the woo+ffers of my RS-1b's and I sware you can hear the vioce of GOD! threw them. The system has such a massive amount if impact it makes you laugh. Good live recorded CD's at even moderate sound levels have the same punch that you feel against your body at a rock concert. The sound is so tight and accurat on jazz and country music it's just amazing.
The guys that fixed my amp made a joke and said "OH your the guy that owns the welder" they were taken by it huge power supply, the technition said it hase endless power.

So I am going to play with it for a while and enjoy the beast. I had a second power outlet with a 20 amp breaker allready in the wall for just for my brystons so I sould have plenty for this amp.

Thanks for all your help,

I took the lid off and was inpressed about how have the amp was biult. It has 24 Hatatchi transistors and a massive transformer that weighs about 40lbs by it's self. It has 8 caps that measure about 6" tall and 3" in diamitor. Its just impressive
Help!! I am looking for a pair of 1b's I owned a pair about 15 years ago, got hitched and out they went. Now out went the wife in comes the new system. I just bought a pair of vincent 991 monos but I need speakers. Can anyone help?
Darinkperih: Glad that things worked out for you. I somehow missed both your original and follow-up posts to this thread. Not only am i glad that you were able to get the Perreaux working again, i'm glad that you were at least initially happy with the results. After having the Perreaux 5150 up and running for almost a year now, i'm wondering what your thoughts are now that you've had a good amount of time with this unit. Is it still shaking the foundation of your building or have you moved onto something else? Sean
P.S. On a follow-up to my original post dated 10/25/03 my original 3150B WAS not working as properly as I expected. I tried to eleminate the hum but could not. However, I was fortunate to find another on (here as a matter of fact) that runs and is running beautifully. I keep an eye out for the 5150B however!!
I am very happy with the amp. I took the front face plate and handles off and had it plated a copper black and then epoxyed clear coated. I changed the power Led to an intence liquid red. I have a pair of Conrad Johnson Premier 5's vac tube amps that I had solar copper 5/8 thick glass face plates made up with beveled edges and the CJ logo engraved in the glass in the same font as factory. Now I can see the warm glow of the tubes. The three pieces look awsome now.

I am now tring to decide on what cable to use my RS 1bs, I have Mit MH-750CVT series II and Monster M1.5's. I am looking at PS Audio 12' lab cables or thier 12' Statement cables or may be Mit tube cables, so I am putting up a thread asking about cables

Thanks for your help guys
Darin: Sounds like you've not only got a very nice sounding system, but one that is also quite eye-catching too. I'll keep an eye out for your next thread as i'll be interested to see where you go with cables. Sean
I have an old friend,who is quite an experienced hobbyist,and,record collector.He runs his RS-1b's with Krell on bottom and CJ PREMIER 8's on top.Believe it or not,he is using PHOENIX GOLD speaker cabling throughout.This is really cheap stuff.I auditioned it in a friend's set-up consisting of Rowland driving Kharma's.It was unacceptable in that set-up.However in the Infinity set up it is like the laws of the universe don't apply.UNBELIEVEABLE sound!You may want to check the stuff out.I'm talking about cables that go for about ten dollars for an 8 ft. run.Good luck.
I have two sets of RS-1b's and I want to use one amp to run 4 bass towers with one pair of high end panels..
Anyone know how to do this and what amp could run that type of low impedance load on the bottom?

For the record with my Older RS1'a (RS1a's) I used 2 bryston 4b's which were a bit bright. Also since they don't double wattage as impedance drops I think the Bryston 4b's run out of current.
I have tried driving the low end,bass section of my speakers with a number of amps,most of them disappointed me.The worst were the Classe mono I think model was 350,(cannot remember)second worst were the Bryston 7 monos,third were the YBA Passion 1000 monos(excellent for mid and high frequencies,Acoustic Reality 1000 monos(ICE amps) were pretty good,but better were the Innersound 1KW amps monos, and THE best are the Electrocompanient NEMO monos.The bass speakers in my system have an impedance of 4ohms. The latter amps are currently in my system.
JM Labs Utopia in the Bedroom Ramy ...... You dah man !!!!

Ramy MANY THANKS! I was considering using newer Bryston 4b SST, and also Classe CA-400 or 350..thanks for eliminating the 7 monos,

I met Innersounds 1 man show and I believe him to be an honest fellow- one I would like to support with my purchase.

The Bryston 7b is a bridged design which can not be used with the Infinity Rs1b crossover though.. and looking inside the Electrocompanient Nemo mono

it looks also to be a bridged design (I see two identical chassis components and a bridge wire...... you can not us bridged amps with the bass section of the RS1b's because they will go into positive oscillation. (very loud painful and costly)

In your RS1'bs ..Did you use a different crossover arrangement? I am using the stock crossover. Or are you using different speakers? I checked your system page and did not see RS1'bs, but greatly appreciate your advice anyhow.
Has anyone used a Classe CA-2300 amplifier for the bass on the RS1b's? The rest are driven by Manley Neo-Classic 250's via a Steelhead. As I've never had the desire to change the RS1b's so I want to see them operating for many years to come.