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Pass Labs - 350.8 stereo vs. 260.8 monos

I have never owned Pass labs amps. However, someone as successful at designing/manufacturing Class A and AB amplification over the long haul as Nelson Pass has to be close to perfecting their craft. I prefer mono amps for the usual reasons but am not against a great-sounding stereo amp. I currently own big Class A mono amps as well as a Class AB stereo amp and based on my listening experience I believe there are sonic trade-offs that make both Class A and Class AB amplification attractive for different reasons.

I am curious about the sonic differences between the Pass X350.8 and X260.8 monos. I noticed with the exception of the obvious power differences, the two amplifiers (and all the amps in the P8 line) have similar specifications. A couple of differences in specifications that stand out to me between the 350.8 and the 260.8s are maximum current (35A vs. 28A) and the wattage at which the amplifiers leave Class A and transition to Class AB (18wpc for the 350.8 and 34wpc for the 260.8s). In this area, the big X600.8 monos seem to be the best of both worlds as they do not leave Class A until 100wpc! I just don’t need that much power.

Although I found a review of the X250.8 stereo amplifier, I cannot find anything on the X260.8 monos so I am hoping some of you have auditioned or own the 260.8s and/or 350.8 and can share your impressions and maybe comparisons to the P5 line or comparable amps by other manufacturers. Thanks for any insights.
mitch2
denon1
329 posts
 
karmapolice, can you please describe what differences you hear between xp-12 and xp-22? Is xp-22 in a different league in compare with xp-12 when  paired with 260.8? I am considering pass 260.8  but not sure if I want to have 2 pieces xp-22.
karmapolice's avatar
karmapolice
254 posts
 
If you never hear the xp22 you will be very happy with the xp12....however the xp22 just sounds a little better in every way .....imagine a good pair of shoes versus your most comfortable.....

I didnt want a two box preamp....I wanted a one box preamp with phono built in but cannot deny I now finally love the harbeth 40.2 ....
mitch2 OP
3,680 posts
 
@karmapolice  
"As for its musicality that is the most subjective aspect of the audition and am trying various preamplifiers to determine if it has that specialness for my room......so far looks like a keeper.."
Have you yet resolved your question about the musicality and "specialness" of the 260.8s?  I am a little concerned with the comment by @rsf507  
"I've heard several Pass amps over the years, great build quality but each time they never moved me. It's like there was no soul to the music."
I have owned Class A, AB, and D that all sounded pretty good.  Currently I have a pair of high-powered Class A amps that do most things very good but I am interested in a slightly different sound.
The amps must have;
-power - at least 250/500 wpc into 8/4 ohms
-dense, rich tonality
-dimensionality - particularly in the midrange (Class D fails this one)
-deep, powerful, well-defined but not overly damped bass
-realistically extended high frequencies (not overly feathery or unnaturally extended or emphasized)
-fluid - cannot have a hint of an electronic or hard sound (Classes A and D have done a better job of this than Class AB in my experience)
-sense of "aliveness" particularly on music that is recorded to sound exciting - Class AB does a pretty good job here IME (the Class D amp I owned with stock NC1200 boards fell short here)



mitch2 OP
3,680 posts
 
Maybe this quote from the Dagogo review of the X260.5 amplifiers describes what @rsf507  was referring to in his description of the Pass sound....
"Another thing I noticed about the Pass Labs X260.5 amplifiers was that, even though they were powerful and dynamic sounding as well as musical, there seemed to be a sense of a type of “restraint” on the music, a sort of “holding back”. Sort of like a power/speed governor on a lawn motor engine, it seems to restrict the amplifier from fully “letting go”, of blooming and expanding unrestricted and quite possibly, preventing the amp from distorting. This invisible “ceiling” seems to somehow restrict the energy and flow of the music “downwards”, by not “letting it go” and allowing the music to flow out, just like it does in real life." 
simpleman68
11 posts
 
Something we all forget about is combination. During auditions, I've heard the same amp sound substantially different based on speaker type, wire, source, pre-amp etc.
On many occasions I've heard the same amp that sounded awful on one speaker, sound pleasant on another. Change the pre-amp or source and they same can occur.
I am running the 260.8 amps on a very revealing speaker with dual AMT tweets per side and think this model is a great combo and mimicks the tubey warmth of other amps I've run.Other SS amps on these speakers can easily be too forward and/or thin.But the same amp in my theater (different speakers) sounds well balanced, dynamic and has great bass punch.
Scott
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