Demo'ing Class A amps, Appreciation Suggestions from those who recently been there

@chorus,
What did you not like about the 120S you sold? Can you describe what was missing for you? Much has to do with speakers too, of course.

I have to ask, and know a few who bounced back and forth between that 120 amp and SS and back to tube later, not having bought the right SS amp. You’ve already demo’d the Pass XA-25, and with "94db" sensitivity speakers, that should be a really good benchmark reference, pending a good preamp and good speaker matching.

chorus, 
Reason I asked is the 120S with KT120s, stock input tubes, and stock caps is kind of a dry sounding amp (imo) in comparison to others I've owned, demo'd, heard several from Cary and Inspire.  The Pass amps, even with a good tube preamp have their own house sound.  Low-watt triode is a different chase, and the right speaker matching is the key there too. 

chorus OP15 posts04-01-2020 12:15am

Cooney,
I had Golden Lion KT88s.
The Leben 300 I just demoed was a step up from the Cary.
I am most likely going with the Pass Int25. No tubes anywhere.
The whole point I am making is the Pass House Sound
is better than ANYTHING I have tried to date.
And by a significant margin.
I am open to being persuaded but please before suggesting anything, please have heard the Pass 25 Amp or Int.
and then tell me what you liked better. Thanks

Not into persuading in this case - now reading back over your initial requirements and referring back to a $5k used budget, but can tell you hands down, if your only reference was a CAD-120S with KT88s, there is a lot more ground to cover and that’s one of my least favorite amps in the whole lineup, of all amps made by Cary Audio. That’s a different beast, less about finesse IMHO.

Live in Pass Land since the early 70s. Was a SS guy for 40+ years.  Started at the same speaker factory too. Heard most of the important amps, way back to modded Threshold, .5 and .8 Pass amps again recently, and now FW forward. Honestly, it just comes down to what sounds best with your speakers for your ears - only you will know that. If you are convinced about SS, it’s a moot point. Of the lot, like the lower power XA-25 as you already noted. Yes, that Leben is neat too. Good choice for SS with the XA-25 amp with a good 6SN7 based tube preamp brings it to another level.  Once again, "tube", not where you are going.  Talked with Nelson about this hybrid combo a few times before, many customers doing that. Have a few friends who ran this same combo with similar speakers throughout 2019, and while we all liked it, all three of the group went back to higher power tube amps or more local tube mono amps in 2020, but once again - all speaker, room, and hearing preference. I still find even the best SS fatiguing for long listening sessions, we all hear differently I guess. Read up on on it, PASS truly takes 4-24hrs to truly warm up and sound right, some leave them on 24x7. My tube monos warm in 45-60 minutes, don't run hot, and sound amazing but won't suggest that. Best of luck on the SS adventure.   

@chorus , 

Are these an accurate photo of your FSM speakers?
http://usr.audioasylum.com/images/3/38319/fsm.com.jpeg

Are you using the 16ohm tap on your speakers when testing?

With FSMs, (I'm not a Tannoy expert - at all) but It's appears (as you are) worth doing more in-depth research on these before buying any amplifier(s). These speakers you have can be a bit picky.  While they seem efficient, doing some quick checking on my end there are repeated suggestions about some struggling with inadequate tube amps to drive these properly, and a few caving in to use "transistors based amps" to get the best out of them. Interesting. Digging some more, now I can see a bit more what brought you to Pass., and why you are reaching out for suggestions. There are more than a few that have matched up the XA-25 in this case. I'd call and talk to Wayne at Pass and again his perspective, first. Then, if you look at any tube amps again, I would look for musical 50w amps before low watt SET, but that's just me reading about your speakers some. More poking around with the Tannoy crew will help . 

Chorus,
Okay. Looking over some old notes and references. Interesting, and a completely different direction from low watt.

"High Current Amplifier" with proper drive for the FSMs. 

SET or tube amps with fleawatt grunt isn’t going to cut it on those.

>>The bass driver units require some current to work effectively and sound right<<

Get this, I even found a few instances up to 250w-300w Threshold Monoblocks or high current Accuphase amps being used with FSMs. For testing old used lower cost amps, got any friends around with a recapped/restored Nakamichi PA-7 Stasis amp or Threshold lying around?

Or, closer to new, it woud take a few grand more over your budget, there is a Pass INT-250 in Peoria AZ, closer to you - listed right here on Agon. Bet this would do it. Good luck :)
https://www.audiogon.com/listings/lisa1b8d-pass-labs-int-250-solid-state?refsource=hifishark

@gryphongryph 
Smooth Class A, try the Belles SA-30, I just got one and it is sounding wonderful

A photo of the inside, 2 large torrids, clean layout, 4 OPTs per side. Never got a chance to hear one to compare. Nice.  Does it sound fairly neutral to your ears, or extended in any way?  


https://www.hifisentralen.no/forumet/attachments/hi-fi-generelt/393431d1470850201-klasse-klubben-sol...

@aldoallen
..LTA describes their sound as tube tone with solid state detail which I think is very accurate...
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aldoallen,
A friend who’s owned the same tube and SS amps I’ve run described his ZOTL amp the same way as you have, and LTA does on their site. And, we’ve both owned solid state amps which have "tube tone. Friend indicated his ZOTL can be "less tubey" sounding, and therefore kept a few of his tube amps to rotate in/out periodically. Been asking him to roll some different tubes in it to compare again.

The other comment on the LTA site about tube amps is... "but their “warmth masks details and can sound thick.". Yes, true for some tube amps, not all. Particularly not with more modern amps with modern power tubes like KT150s. Seems LTA/ZOTL was looking for a hybrid sound and approach. It’s great to see different approaches.

I would’n’t mind demo-testing the ZOTL40 Reference amp with my custom speakers, to see what it can do, and how different it is versus some of the more capable Class A>A/B solid state amplifiers we all know. Grew up past 40 years transitioning through very "tubey" sounding solid state Mosfet designs with dual mono torroids and really enjoyed those too. Then, on to tubes. Have great appreciation for those blending both together.

Noting you’ve owned CODA and the Rocket88, both with their own signature sounds, do you feel your ZOTL leans more to SS than tube amp sound then? If you could change the sound a bit more with your ZOTL, what would it be - if anything?

@aldoallen
.. I can’t think of anything sound wise I would change but it is definitely not audio jewelry. Just a plain black box...

aldoallen,
Congrats. It is unique black box. Not like most other 10w amps. My colleagues ZOTL displaced a former Cary -and- Dennis Had Inspire amp (all stock, unmodified) yet he does like detail and fast punch over lush-plush-bloom triode tube sound. And, to read yours displaced a Coda 10.R SS with the first 25w in Class A - is notable. Synergy with speakers is everything. Glad u found it for your ears and prefernce. :)

@chorus

Are the INT-25 and XA25 still in the running?

Different amps, but also wondering if you already reviewed the INT-60 too... or heard one in person somewhere.