Thiel Owners

@dsper, A room of that size could accommodate full range sound, the only thing that might be holding back that possibility is the c-j amp. Now, I like and have used c-j (though ss) in the past, and I don't mean to harp on this, but I think the resale on c-j stuff is quite good. You might be able to get a visually less imposing speaker than the CS5i's that could offer deeper frequency response and still meet your other criteria, if you would consider other amplification that met the loudspeakers needs rather than getting speakers that met the amps limitations.

@coop_301 , It appears that for a fairly reasonable charge you could have the balanced output voltage customized:

Okto Research

Okto dac8 Stereo D/A processor | Stereophile.com

Okto dac8 stereo DAC Review | Audio Science Review (ASR) Forum

Recommended Components Fall 2021 Edition Digital Processors | Stereophile.com

@unsound ...if you would consider other amplification...

You make a very valid point.

The other part of this for me is the desire to try a tube amp setup. For example the CS.5 is a 4 ohm speaker that is supposed to be able to run on 30 wpc per the Stereophile review link that Tom Thiel shared. The CJ LP66S is rated at 60 wpc at a 4 ohms. Along with jazzman7's postive comment, maybe I should try a pair. Not a real expensive experiment at current used prices for the .5's.

I appreciate the advice. Thanks!

@dsper, 

Keep in mind that the Thiel specs at 87dB/2.8V/1M which is confusingly not the same as 1 Watt. Considering the 4 Ohm nominal impedance, it's more like <84dB sensitivity. Jim Thiel told me that his power recommendations were based upon the assumption that quality ss amp that could appropriately double down be used and that for example that if one using a Thiel speaker with a 4 Ohm rating with a tube amp one should double the power of those recommendations. Furthermore, the c-j specs seem quite generous:

lp66s2man.pdf (conradjohnson.com)

with a rather high +/- of 1.5 THD and a somewhat limited bandwidth of 30Hz-15Khz. 

Considering the limited bass output of the CS .5's and that they can seem a bit tippy without any treble roll off of their own, and the fact that tubes overload more gracefully. it would seem as though it should all work out. But in a room of that size you might be at the limits.

Of course, due to the small size of the CS .5's, they are not at all too cumbersome, and it wouldn't be too difficult to move on from them.

Sure, I guess it's worth a try. 

@dsper 

From 1996 to 2004 I had my .CS 5s hooked up to an ADS A2 integrated (80 watts per side into 8 ohms) and it was decent, but then in 2004 stepped it up to Bryston rig - 3BST with BP20 preamp, and it made for a big step up in SQ. Very same room and speaker location as displayed on my virtual systems page.  Not a small room, but plenty of sound. And if more bass is desired, one could always work in a subwoofer.