Thiel Owners

I've mentioned this before, but perhaps it's worth mentioning again. Claims of stability into a given impedance doesn't really say much, other than the amp won't go into oscillation when faced with such an impedance. Sure it's nice to know your amp won't blow up when confronted by such a load, but it doesn't indicate how it will perform when dealing with it. How much power can it deliver under such a load? Failing to double down into lower impedances suggests that frequency linearity could be compromised at the amps high power outputs. Often times amplifiers start to strain and sound hard before going into actual clipping.

Altx's CS 2's have a fairly easy and particularly smooth impedance for any speaker never mind a Thiel. Probably not an issue for him.

https://www.stereophile.com/content/thiel-cs2-loudspeaker-measurements


Neither of the afore mentioned intergrateds are spec'd below 8 Ohms.

The Ayre EX 8's measurements:


https://www.stereophile.com/content/ayre-acoustics-ex-8-integrated-hub-integrated-amplifier-measurem...

are rather disappointing to my eyes for such an expensive ss amp.

Still, for the CS2's if not pushed too hard in a smaller room the Ayre EX 8 could work.


Unfortunately I couldn't find independent measurements for the Hegel 390i, but is spec'd for much higher power output into 8 Ohms.


https://www.hegel.com/products/integrated/h390

The Hegel 390i will probably work for the Theil CS 2's.


If an amplifier can double down into lower impedances, they'll likely list those specs as bragging rights. If an amplifier can't double down (or come reasonably close) into lower impedances, It's less likely they'll list those specs because they're not proud of them. 

sdecker - regarding the 2.4 vs 2.7, I can supply some contextualizaion and personal observations. I don't know either speaker well, but I heard both in September 2012 when the 2.7 was finalized, although our working comparisons were between the 2.7 and 3.7, which is a different story.
I think the 2.7 is an extraordinary speaker, but built and priced by a different standard than Jim's ethos. I also think that it veers away from the traditional role of the model 2, which was the svelte little sister to the model 3 big brother. The model two had always used a smaller diameter midrange than the three, along with the smaller woofer with higher crosspoint - resulting in less doppler distortion, lower inertia, and a more nimble, lithe personality for the model 2.

The 2.7 was developed under different circumstances and therefore different rules. Thiel needed a new product after Jim's death to demonstrate that they could produce a credible contender without him. I say it is a success, but not the same contender that Jim would have designed, because Thiel no longer had his considerable chops and long-range vision. Jim was working on a CS7.3 with a new, improved coincident, passively coupled high driver. (The CS7's high driver was developed in the CS2.3). That 7.3 high driver would then be tumbled down to the 2.5 - the way Jim Thiel did things. All those plans went on hold when Jim died and a successor engineer or company was not found to carry the torch.

A far simpler and executable fall-back plan was to take, as you mentioned, the extant 2.4 bass system including the woofer, passive and enclosure volume and mate it with the extant 3.7 wavy high driver, making XO changes to accommodate. One circumstance is that the higher woofer to mid crosspoint necessitates a very large capacitance coax feed. The 2.4 has 30uF feed capacitance and the 2.7 has 416uF, including a 400uF electrolytic. That's the only electrolytic feed cap since the 1976 model 02, as far as I know.

So, yes, the CS2.7 is a valid Jim Thiel tribute design with first order slopes, minimal diffraction and lots of learning rolled in. And it is good. Some forum members here and elsewhere choose it over the 3.7. But it is in some ways less elegant and demure than the next model 2 from Jim would have been.

Enjoy the ride, wherever you go.

@jazzman7 "I'd be curious to know if you ever tried using your Hegel H190 to drive your Thiels ... and if so what you thought of the pairing.Hegel specs say their integrated amps are stable down to 2 ohms.So if so, all that is left is if it's a good sonic match."

No have never used the Hegel on the 3.7s.  The main system is in a larger room (16x18 with 10 foot ceilings and a tray ceiling on top of that and open into other spaces bigger than the 16x18).  I was using a Modwright KWA150SE (along with a Modwright LS26.5DM preamp) to drive them and tried a Class D (Mivera), and was shocked that it bested the Modwright.  I now use the EVS 1200 amp (same module as the Mivera except dual mono and with mods) to drive them and it's plenty of power and sounds great.  I traded the Modwright amp straight up to a dealer for the Hegel and sold off my preamp, DAC and amp I was using in the secondary system.  Am quite pleased with the Hegel.  I'm using a small PC music server with JRiver since the USB DAC in the Hegel 190 is limited and it can't do DSD (I use JRiver to play it back at 176.4 along with a USB to coax converter).  If I were to use a Hegel (integrated) in the main system, I'd go with one of two models above it (I'll probably at some point convert the DSD files and have them somewhere on the network so I can just play them back over ethernet (the Hegel can use UPnP) and do away with the PC - just have other things I'm working on for now and don't use the secondary systems all that often).

@cascadephil  

Thanks.

Bryston 3BST / Bryston BP20 has been my amp / preamp combo since 2004.   Been driving CS 2.4s since 2011.  Before that CS .5s.    When I purchased used pair, my dealer still had brand new CS 2.4s on the floor, and was my Bryston dealer as well.  Made it much easier to audition  both the speakers and the ampflication, as well as the pairing.  Won't be so easy next time around.  And my local dealer just retired and closed his doors.  Been thinking that should I move on from the 3BST, should I entertain going with an integrated, and if so what integrated.  In that regard Hegel has been on my radar.  Hence my question.

I had a Bryston 3BST in the secondary system (along with an Odyssey Candela preamp and a Meitner MA-1 DAC) driving Ohm Microwalsh Talls (augmented by a Rel Strata III sub).  I had a friend bug me about Class D in the summer of 2017.  I had last seriously listened to them at the Capital Audiofest in 2015 and I thought they had gotten better but not quite there yet.  I told him I would look again at RMAF in 2017 and that I'd probably get one as I had multiple systems and I was sure by this point I could at a minimum replace something like the Emotiva XPA-200 I had in one system.  I ended up getting the Mivera SE amp.  I broke it in using the secondary system and just put it in place of the Bryston 3BST.  It smoked it right out of the box (was shocked by that much of a difference and surprised how much better the system sounded - always thought the speakers were more limited but was wrong).  I ended up using that (the Mivera, where it bested the Modwright amp - even more shocking and I had a Bryston 14BSST before the Modwright) in the main system.  I traded the Modwright amp for the Hegel (then sold off the amp, preamp and DAC I had in that secondary system) and then I got the EVS amp and moved the Mivera and sold off the Emotiva amp.  I still use the Mivera in the main system for HT (my main system in an integrated AV system and it is a pain to get behind it so it is easier to move the Mivera which drives the 3.7s with ease).  I wanted to get a higher end Hegel that had a less limited USB but just couldn't justify it for the secondary system.  I'm sure Hegel would drive Thiels quite nicely.