PASS Amplifier suggestions

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jadedavid

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I'm thinking of trying out a Solid State amplifier.
I have always used tubes but want to try something with some more power and also like the control of the bass from a solid state amp. Coming from tubes, a liquid mid range is very desirable.
With a somewhat limited budget this will be a second hand purchase.
Pass lab amps keep popping up in my search, seeming to check most of the boxes.
I am most interested in hearing about the sonic differences of the many amp series that he makes.
Not interested in the First Watt series at this time. More interested about the differences from the X, XA, .5 and .8 series. ( or of any others in the line that I may have overlooked).
I read one rather lengthy review on another forum about the 30.5 vs 30.8. While they thought that the .5 was more tube like, they thought the 30.8 to be all around superior.
Also, besides the differences from series to series, do the amplifiers in the same series (like 30.5, 60.5 etc) carry a similar signature?
Any experience and information would be appreciated.
 
While amps in the same series generally have the same sonic signature, each individual amp has their differences. From experience, the XA60.5 were superb but the XA100.5, to my ears was a little too flabby in the bass and a little uncontrolled. Moving to the XA60.8 was even better. While not as tube-like, they were quieter all around, sweet and smooth with clearer/cleaner detail. Plenty of power for my JBL and Studio2.

Friends owned the X350.8 on Salon2 and that was a wonderful combination. Approx 17 wpc of class A before switching to full class AB but still sweet and 3D and air with a little bloom.

Pass amps are excellent.

One on my absolute favorites, if you don't need a ton of power, is the XA25. An absolutely superb amp that, once broken in, is just about perfect. With your AudioKinesis Zephryn 46, it should be glorious.
 
Thanks for the info Joe.
One of the reasons to go for more power is that I am also getting the itch to get some new speakers (yes it's an illness).
I want to broaden the possibilities in speaker choices.
 
If you don’t mind or can handle the heat, please consider XA amps first.

If you could let us know what speakers you are thinking about in the future, maybe we can come up with some recommendations on amps.
 
A great question, as I don't know which speakers to go with.
I like a warmer, somewhat old school type sound. Soundstage and depth are high on my list. Good detail without any harshness.
Music choices are blues, fusion Jazz, acoustical. Think Keb Mo, Jesse Cook, Gregory Porter, Yello etc.
I have the acoustical room from hell. Big floorstanders such as Legacy Focus overload the room and actually produce less bass than smaller speakers.
So probably a 10" or equivalent woofer system is about the max.
Not sure what combos of Pass / speakers plays well together.
Perhaps Sonus Faber, Harbeth, Von Schweikert????
Anyone please chime in with your experiences that might meet these parameters.
Thanks
 
Joe's Pass descriptions being pretty much spot on IMO so I'll just add that a year and a half ago I transitioned from tube amplification to a pair of Pass x260.8 monoblocks. They drive a pair of Revel Studio 2's to perfection and I would wager they would do so with whatever speakers you choose in the future. Also of note, the 260.8's being A/B designed amps have the greatest amount of initial bias into Class A of any of the A/B Pass amps, save the big '650'
 
I think the 260.8 have about 34wpc of Class A before switching.

I absolutely loved my Studio2 with a pair of xa60.5, then a pair of xa60.8 amps. Stunning.
 
If I recall correct, the xa are pure class A? These may limit your speaker choices since you mentioned wanting more power. If you do consider the xa series then I would assume First Watt may be back on the table. For example, the First Watt F6 and the Pass XA25 (that Joe has, or had :)) have identical specifications.

I had a F6 and it was a wonderful amplifier. It did not have a ton of power but it sounded glorious; one of my favorite amps that I have owned. It was part of my relearning and one amp that I kind of wish I had keep. Like the XA25, it had 25 WPC into 8 ohm and 50 WPC into 4 ohm. Depending on speakers it may not be enough.

If more is what you are considering then, probably not so much :)....
 
I have a feeling his next set of speakers will require some power and First Watt and possibly XA25 might be out of the question.

Once we get some idea of speakers going forward, it’s almost meaningless to think about amps.

Don’t be fooled, Pass amps provide a lot more power than you think for any given model.
 
As usual, Joe is right. From the Stereophile XA25 review:

Pass Labs specifies the XA25's output power as 25Wpc into 8 ohms and 50Wpc into 4 ohms (both equivalent to 14dBW). However, as you can see in figs. 4 and 5, the amplifier exceeded its specified power output at the clipping point, which we define as when the THD+noise equals 1%. At that THD+N percentage the XA25 delivered 80Wpc into 8 ohms (19dBW) and 130Wpc into 4 ohms (18.1dBW). It appears from the shape of the traces in these graphs that Pass specifies the XA25's power as when the THD+N is close to 0.01%.

https://www.stereophile.com/content...er-amplifier-measurements#mEWGSDfb160gUGMt.99
 
Yup, I would say they are wonderful amplifiers. I also agree with what Joe was saying that it might be meaningless to decide on an amp until he decides which way he is going in speakers.
 
jadedavid said:
A great question, as I don't know which speakers to go with.
I like a warmer, somewhat old school type sound. Soundstage and depth are high on my list. Good detail without any harshness.
Music choices are blues, fusion Jazz, acoustical. Think Keb Mo, Jesse Cook, Gregory Porter, Yello etc.
I have the acoustical room from hell. Big floorstanders such as Legacy Focus overload the room and actually produce less bass than smaller speakers.
So probably a 10" or equivalent woofer system is about the max.
Not sure what combos of Pass / speakers plays well together.
Perhaps Sonus Faber, Harbeth, Von Schweikert????
Anyone please chime in with your experiences that might meet these parameters.
Thanks
Click to expand...

Pass and Harbeth go together very well. I do have the INT-60 with 30.2s in my summerhouse, and it is a smashing combo if you like a good bass and a somewhat warmish sound, yet with a transparent upper register. The turn-side is a slight lack of speed.

In my main system I had the 250.8 with Magicos, and those played well also. At some point I just desired a slightly faster amp and a little bit more articulated sound and switched to Soulution, which IMHO nails it all.


Sent from my iPad using Tapatalk
 
joeinid said:
I think the 260.8 have about 34wpc of Class A before switching.
Click to expand...
Class A amps sound different (better) than Class A/B at all power levels, not just at or beyond the transition point. Quoting Nelson Pass:

Class AB has a moderate bias current, and Class A has a high bias current. Class AB push-pull amplifiers are hybrids between Class B and Class A. Class AB run Class A at low power levels, and become Class B amplifiers at output currents determined by the bias.

Higher bias doesn’t just move the Class A transition to higher ground – it has a profound influence on the amplifier at all power levels. It lowers the distortion at low levels as well as high levels, as seen in the distortion vs power curves for an amplifier with the bias set at different levels.

The benefits of high bias current extend beyond simple harmonic distortion measurements – you also get a reduction of intermodulation distortion (arguably more important), and a lower, more consistent output impedance. As a corollary benefit, the heavy hardware required to support Class A operation will show better thermal stability and will deliver better performance into difficult loads.
Click to expand...
 
The KEF Reference series would be worth consideration.

I know you are looking for Pass in this thread but as you are sort of looking for an overall change, I'd really encourage a listen to the Vandersteen speaker & amp combo. Some of the guys more familiar may be able to provide some model numbers. I just know I really enjoyed what I heard from them at the show. Since you already have the DAC & preamp the Vandersteen system would drop in right where you need it.
 
The Sandman said:
Class A amps sound different (better) than Class A/B at all power levels, not just at or beyond the transition point. Quoting Nelson Pass:
Click to expand...

I agree, given the choice, I always opt for the full class a version Pass amps. The xa60.8 are still among my favorites. I’ve always wanted the xa160.8 but now with my Avantgarde speakers, high power amps just aren’t necessary.
 
I love my INT-250 with Studio2. I have used INT-150 and the INT-250 is significant upgrade. I do not need to look further.
In the past I have used X1, Xono and X350 with Thiel. This setup served me well for over decade until I moved to tube. I love Pass sound and decided to come back to it.
 
The INT-250 looks like a serious amplifier.
I had not really thought of going integrated but it does eliminate a power cable and interconnect.
And you don't have to be concerned with the separates (pre / amp) playing well with each other.
Worth looking at.
 
jadedavid said:
The INT-250 looks like a serious amplifier.
I had not really thought of going integrated but it does eliminate a power cable and interconnect.
And you don't have to be concerned with the separates (pre / amp) playing well with each other.
Worth looking at.
Click to expand...

Its really excellent. I think it competes with the XP12/X250.8. The separates give you a little bigger soundstage and separation, but it’s close. A really good PC on the INT-250 will make a big difference as well. Just note, it’s a big honker!


Sent from my iPhone using Tapatalk
 
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