Disappointment with Pass Labs - I'm looking for something else

While it is true that tubes sound good with Klipsch, so does many solid state amps as well. Midfi, the slightly.warm sound of B&K does the trick, Higher end SS Conrad Johnson solid state sounds delicious. Mcormack amps nice! Don't use the High Definition Audio Research SS amps, a waste of time and money, too bright!  I like the high sensitivity of Klipsch because it don't take a lot of power to get em going plus they are revealing of all the fine details and its like being in a front row seat at a concert.

Cornwall III's can sound dull, muted and warm with many amps/preamps. The new IV is much more alive, lively and sharp. I love my pass gear with Heresy IV and LaScala. Gorgeous, huge soundstage and sweetness that tames the highs of these speakers. The VIII's from Klipsch were much more dull sounding than what they make today. 

I have a set of XA60.8's and an XP-10 running Klipsch version IV's as well as Fleetwood Deville's. The sound is the best I have had in 35 years of HiFi. I know a pre-amp upgrade will improve it further as the XP-10 does lean slightly warm, Even so the sound is wide open and huge. 

The #1 ingredient to a great system is the room, then the speakers, then the pre-amp/amp, then the source/dac. Then cables. The kicker is....synergy. Add in something that doesn't have synergy when all connected together and it can sound awful. 

I wouldn't trade my Pass Labs for any other gear as I have not head anything better in my space, with my gear. But for others it may sound dull, lacking or even bright. All depends on the synergy. 

If you want a nice wide open soundstage, the Heresy IV will do much better with your pass gear than the CWIII. They can do big, sweet soundstage. They are not bright nor warm. They image like mad and sound stunning with Pass Labs. The 30.8 would sound gorgeous with them if they were set up right. Also, you have a world class DAC but it also leans warm. You have a warm amp, warm DAC and warm speakers. Yes, CWIII lean warm and muted. 

I believe if you changed your speakers you would be much happier. The Fleetwood Deville's are a huge step up even from my LaScala in every area. Even something like a set of KEF LS50 could bring you what you look for. Dynaudio bookshelf. B&W also can be fantastic. 

The gear you have far outclasses your speakers here. Even moving to Cornwall IV would shock you as they are much better than the III. Bottom line is that you have world class electronics. The synergy with the speakers is off. 

Audioholics recently measured an X350.5 Pass labs amp. It did not do well!
https://youtu.be/uDbfwCo0a3I

@hifi59 ugh… zombie thread. Most Pass amp amps “don’t measure well” they aren’t designed to “measure well”. They are designed to sound good. Read Nelson’s take on this on the website.

@hifi59  That´s the first time I've ever seen a Pass amplifier measure at less than specified power.  On multiple other occasions reviewers have explicitly noted that the amps are very conservatively rated.  

See, e.g., this stereophile review of the XA30.5: 

"Fig.4 shows how the THD+noise percentage in the amplifier's output varies with output power into 8, 4, and 2 ohms. While the XA30.5 may give 30Wpc into 8 ohms in class-A (14.8dBW), the distortion at this power level is low, at 0.015%. The amplifier doesn't actually clip (defined as the THD reaching 1%) until a much higher power level: 130Wpc into 8 ohms (21.14dBW). Even higher powers were available into lower impedances before clipping: 195Wpc into 4 ohms with both channels driven (19.9dBW), and 332W into 2 ohms with one channel driven (19.2dBW)."

And another for the XA25:

"The INT-25's output power is specified as 25W into 8 ohms and 50W into 4 ohms, both equivalent to 14dBW, with a "class-A envelope" of 50W peak into 2, 4, or 8 ohm loads. With "clipping" defined as when the THD+noise reaches 1%, I found that the Pass Labs amplifier with both channels driven at 1kHz clipped at 60W into 8 ohms (17.8dBW, fig.4) and 98W into 4 ohms (16.9dBW, fig.5)."

I think the X350.5 was actually broken.  As he notes, obviously the DC offset needs to be re-biased, and given that power behavior, I think it's in need of more substantial service.