ARC ref 210 vs ref 150

Looking into used market for upgrading my amp and considering these. Which would you guys choose and why assuming space is not an issue. I have ARC ref5se pre, levinson 331 amp driving Dynaudio confidence c4.
I've had both in my system for direct comparison. The Ref 210s provided slightly more expansive and deeper soundstage and (my guess is) should provide more power at fairly extreme listening levels.
My test did not go beyond 95 dbs at my listening position.
But in all other respects including grip, palpability and an overall more realistic and natural presentation, the Ref 150 was vastly superior. The slight percentage loss re soundstage was hardly noticeable as that characteristic is provided in spades by all ARC tube amps. Furthermore the low and mid bass was better delineated and more palpable with the Ref 150.
My feeling on ARC gear is that up until the Ref 150/250 series amps, the overall presentation was wonderful and well worth the price of admission, albeit a bit too much on the side of light and airy---diaphanous
I think that problem has been substantially mitigated if not eliminated in the 150/250 series, especially so with KT 120s and now KT 150s.
Hi Gpgr4blu

I am considering a Ref 150 (non SE) to drive Vienna Acoustics Kiss speakers. My concern based on hearing non Classic Audio Research amps is that they veer more towards solid state than tubey and your comments that they are on the side of light and airy strikes a note as I like bloom and warmth, moving on from Krell. My other consideration was Ayre.

What is your system? Do you have any views of pairing a Ref 150 with a Cary SLP 05 preamp (which I have now).

I own the Ref 150 SE. It's a wonderful sounding amp.

As some may know, ARC approved the use of KT-150 tubes in the "regular" Ref 150. IMO, the KT-150s bring a sense of depth and hue to the music. IMO, my amp is warmer sounding with KT-150s than the original stock KT-120s. IMO, the SE version is even better sounding than the non-SE version.

Of course, amp/speaker matching is always an issue. If you still have a chance to audition the Ref 150, try a listen to one with KT-150 tubes.

Can't speak about the Ref 210 ... never heard one in action. That said, it's worth mentioning that the Ref 110 and Ref 210 were both replaced by the Ref 150 and Ref 250, respectively. The current Ref series (not SE) had beefed up power supplies (doubled in the Ref 150), was designed to be driven with KT-120 tubes (as compared to 6550 "Winged Cs" in the Ref 110) and took numerous other circuit changes.

I can only surmise that the more recent "150" and "250" models are better sounding than their earlier counterparts, the "110" and "210" models.
The Ref 150 is a great amp with original KT 120s or with KT 150s which I installed at Dave Gordon's recommendation prior to introduction of the SE series.
They both sound great, the KT 150s slightly more so IMHO. Not a night and day difference so fear not if you go for an original stock Ref 150.
As to my light and airy comment--this does not relate to warmth and bloom but a bit of steely coolness in the warmth and bloom that the Ref 150 vanquished.
The Ref 150 has tube bloom in spades with a palpability that is simultaneously well rooted in space but holographic--a trick that I have heard from no other amp.
The Ref 150 is the best overall amp (together with the Ref 250) that I have heard in my 20+ years as an audiophile. This comes from someone who has never purchased a solid state amp. I believe it would make a great sound with your speakers which I have heard. I cannot comment on your pre as I have not heard it.
I did prefer my amp over the Ayre monos. In fact the only solid state amps I have heard that I like almost as much as the Ref are the D'Agostinos. In short, I highly recommend the purchase. Of course, if you can listen to it first, that wuld be ideal.
Sounds like the 150 is the way to go vs 210 monoblocks. I just thought 2 amps for price of 1 plus more power.
Unfortunately, I cannot listen to it first before I purchase. Your comments hit my concerns right on.

It's interesting that you have heard the Ayre mono's and preferred the Ref 150 to them. In what ways was the Ref 150 superior.

I have heard the Ayre mono's AB'ed with the no frills D'Agostino Master Power Classic (likely not the Momentum you heard). In this case, with Avalon speakers, the Ayre's sounded better and more forgiving (read rolled off) to me.

With regards to the pre, it needs to be matched with an amp with a fairly high input impedance. The Ref 150 SE is listed on the ARC website as having one of 300 kOhms and that should be sufficient. Is that the same with the Ref 150?

“a palpability that is simultaneously well rooted in space but holographic” – man that sounds tremendously good.
Mickey, you wrote "[w]ith regards to the pre, it needs to be matched with an amp with a fairly high input impedance. The Ref 150 SE is listed on the ARC website as having one of 300 kOhms and that should be sufficient. Is that the same with the Ref 150?"

The answer is yes. The specs between the Ref 150 and 150 SE are almost identical. Ditto the GS 150. You should note that the Ref 150 (SE and non-SE) and GS 150 only have XLR inputs ... no RCA/SE jacks.
The Ayres were very very good. They were not quite as powerful on the bottom end as the Dags.
But the difference between the Ayres and the ARC was simply the difference between excellent tubes and excellent solid state. Better bloom, 3d presentation and palpable images from ARC. Slightly greater transparency from Ayre. In many other areas, they were virtually indistinguishable.
I am a tube fan. So, for me a great tube presentation beats a great ss presentation.
A ss guy will prefer the Ayres.
I think I would prefer the ARC too.

Thanks that was very helpful.
I recently took my Ref 75, which I had retubed with KT 150's, back to the dealer for upgrade to SE status. Fortunately, the distributor OK'd doing the SE upgrade without the cost of new ARC 150's. I was able to compare my Ref 75 with KT150's, with the dealers 75 SE. I can confirm that the SE upgrade to new capacitors etc, gave a similar increase in performance, to the KT 150 retubing. My original thought was most of the performance improvement was in the tubes, not the other changes in the SE upgrade. This, to my ears, appears not to be the case and you need the full SE upgrade package, to get all the benefit out of the 150 tubes.