Infinity Irs Beta

I recently purchased a set of the Irs Betas. My system consists of a Krell Kct Preamp, Krell Kps28 CD player, Krell Fpb400 cx which I am powering the mid,high panels and using the cast interconnects between them and a Krell Ksa300 for the bass towers with the servo unit. Would tubes on the top end be a big improvement? Any folks here run tubes on their Betas and have you compared the two? It sounds wonderful as is.
Why the middle name is IRS?
I used to own them...Awesome speakers! And I mean great!! The bad news is they might sound fine now,but will definitely sound better with a good(relatively powerful) tube amp on the panels....I ran top quality Audio research units on mine.You definitely want solid state on those bass towers though.that's where the Krells should go,which is what I was using on mine....Good luck.
Back in the day, Infinity made a series of high-end speakers called The Infinity Reference Standard, (IRS) series.

These include:

The IRS Beta
The IRS Delta
The IRS Gamma
The IRS Epsilon
The IRS Omega
The IRS Sigma

So really, the name the OP uses is correct. I was an Infinity dealer for many years and even sold a few of each of the above, except for the IRS.

Out of the hundreds and hundreds and hundreds of speakers that I have personally owned, the Beta's are still the one speaker I wish I never had sold. Still one of the best speaker systems ever made....IMHO.
I read somewhere that when Infinity was designing the IRS series speakers they used audio research tube amps on top, I have the IRS Epsilons... they are awesome speakers that sound very similar to the IRS Beta's aside from the bass output, congrats on your recent purchase.
Betas are excellent speakers when they are good... but sometimes they show their age. They're around 25 years old. The bass modules and servo could use a 21st century update.
Next to impossible to find parts for the tweeter,midrange panels.
Isn't the "IRS" also known as the IRS V (5)?
While attending technical school (around 1983) I joined a group of EE's for a tour of the WFMT studios in downtown Chicago. WFMT had a recording studio/hall with a pair of the gigantic IRS modules 10-15 feet up on the walls.
BTW, we asked the head engineer where he attended school.
His reply: "Self taught". -Mind Blowing!
The last version of the IRS was the V (5), but the IRS series all started with the IRS I, then the II, then the III, then the V. There wasn't an IRS IV.

They are indeed MASSIVE speakers and sound that way too. I've heard them several times and the word DYNAMIC always comes to mind.
So good to see Sirspeedy back in the rooms commenting again! Yes the IRS Beta's are a fine (great?!) speaker. I have the model before that one (The Infinity RS-1B's). I agree with all the comments above. Tubes on top/SS on bottom. I have used Audio Research VT 100 and Hurricanes on the top and now MacIntosch MC 275 (2 of them in mono @ 150watts per).

RWD (Rick)
Paul McGowan (PS Audio) owns both IRS Vs and Betas. He is friends with Arnie Nudell and has done extensive updates to his Vs. He has not mentioned working on his Betas. From Paul's website here is an interview with Nudell where he mentions his own preference for tube amplification, at least up to a point.
The last IRS I heard was at PS Audio in February 2014. They hosted the Colorado Audio Society meeting so that they could show off their new DSD DAC.

If you guys ever get a chance to hear these monsters, it's truly an experience not to be forgotten.

I've heard their Beta's too. Still one of the best.
Geez, that set of IRS V in the video above is pristine. Every driver has been restored to like-new condition. I'm sure they've gone through the wiring, bass amps and crossover also.
Two of the absolute top systems I've ever had the pleasure of listening to are the IRS Betas owned by a good friend's brother in law driven by ARC electronics and the IRS Reference 5, and specifically owned by Arnie Nudell at one time himself where the speakers were completely rebuilt by master speaker magician Bill Legal, over 500 hours he told me rebuilding them. That IRS 5 system IS the most magical of any speaker I've ever heard in that they presented small scale music chamber music, as an example, with the finesse and focus of a mini-monitor and Beethoven, the most DIFFICULT music for any audio system to produce IMHO closer to the live event. Still, you have to hear Beethoven live to experience what his music is all about.
Rick, How did they sound with the Vt100 on top?
Rvito, The ARC VT100 (mk2) sounded quite good. I only went to the Hurricanes for more power (which I really didn't need). Remember I listen at a lower lever then most (most of the time). The ARC had more of the warmer tube sound (but not of the early 70's). A GREAT amp if you can get it and I also understand the MK2 is better then the MK3.

RWD (Rick)
Would a Arc 100Vt be enough for maybe moderate listening levels ?
What's the size room and at what level do you listen? Also, do you prefer classical (large, dramatic or small)to other types of music? I love classical and at most times the VT100 was spot on.

RWD (Rick)
Room size is 20 x 25 moderate at the most and classic Rock, Jazz, Classical.
Rvito, your room is considered (by me at least) moderate to large. Mine is about the same size. I had no problem driving the top end of the RS-1B's with the ARC VT100mk2. You should be fine with them. What other amps were you considering?

RWD (Rick)
maybe a Arc Ls25Mk2 with a Vt200 Amp
I also had the LS 25mk2 (the best-not the Mk3). Wonderful. I think this would be fine.
The VT 100's would be enough power on the top and you can get good levels of volume,unless you are in a very large room and like to break plaster.....I had Infinity RS-1 A's and B's before I had the Betas.I drove my Betas with Audio research 100 watt mono blocks on top and either Krell or Threshold SS on bottom(I don't remember which,sorry).

A couple of things...First off the mid panels "are" the star of the show if driven correctly.The bass is fabulous,but sheesh,those mid panels are amazing.....I was a pal of the late(and wonderful guy) Bob Reina,who at the time took me over to Michael Gindi's home to hear his version of the Betas.Michael used to write for TAS and modified his Betas....I was not sure his mods were all that good,but he knew what he was doing for sure....he re-wired the panels and placed heavy planks on top of the woofer toweres,something I did not think necessary at the time....but...I "do" remember that he(and I believe the reviewers of the day)blocked off the uppermost portion of the tweeters.The highest one at the very top.I did as well,using simple tape.I just blocked the "upper half",which gindid did as well.If I remember correctly,this gave the speaker better balance....and...if in good shape,these speakers make a mockery of the mostly way overpriced speakers of today....they are fabulous!

Good luck

P.S. hello Rick! I remember our tome at Sid's.You were and still are a fine fellow...I've left the hobby to pursue playing and studying music.I only posted here because the Betas were sorely missed after a move out of N.Y. and they were wonderful speakers.
Mark, great hearing from you!! My e-mail is Perhaps (if you are still in the tri-state area) we can catch up again. Hope Sid is ok?

RWD (Rick

P.S. Correct about the tweeter and the tape (or a small plate). I did that to my tweeters.