Hi. I recently added a Pass XA-25 amp fed by a Holo Audio Serene preamp. I really do like the clarity and solidity of this combination driving my Klipsch Forte's... Previously I had an Elekit TU-8600S 300B SET amp. The Elekit did some things quite nicely but way too noisy and the bottom end was muddied. I think if you're after tube sound, you can add it higher up in your signal chain. 

@audiojan I think you'll get over the distraction.  but it sounds to me like you'll go bak to tubes.  either way, you'll have a good system.

I may have discovered why this INT-25 is not working well... to get to a volume that’s about conversational, I need to turn the volume up to 50 (the volume goes to 63). I borrowed a new INT-25 from my local dealer (their tech is out, otherwise he could’ve looked at it) and on that unit at about 30 it was quite a bit louder than conversational.

Could it be that I simply struggle with the amp because of a gain issue?!

Certainly, you cannot make any judgements about INT-25 from the faulty unit you first received! Is it possible to retain your dealer’s loaner long enough to make a proper evaluation? Sounds like you have a solid enough relationship to make this happen. It would be a shame to let a (rare) faulty unit dominate your conclusions. Definitely sounds like a gain stage somewhere in the circuit has "crapped out" - maybe passing signal without the appropriate gain.

To @audiojan The reason I asked about new/used and "factory boxing" is I have been sort of tracking along with different audio things getting damaged in shipping.

Last batch of larger and heavier items I shipped were all hyper bubble wrapped, foamed, double-boxed, after friends having very nice components getting damaged and/or rattled apart inside. .

Ask:

• Was the INT-25 shipped to you in the original factory Pass Labs box?

@decooney it was used, but I did talk to Pass Labs technical support and they were as stumped as me

To @audiojan - There are plenty INT-25 units out there running perfectly well. Well tested they are leaving the factory. I live 15 minutes from Pass Labs btw, tons of it around me. Never heard of this kind of failure before, so once they check it out, will be interesting to understand what they find inside. Bad part or did something come loose inside.

So whoever you got it from or possibly some kind of dropped-box issue during shipping can happen. Would likely require a pretty heavy drop to loosen anything inside - one other guess.

Ask:

Was it brand new or used, and did it come in the all original Pass Labs box and internal packing inside when you received the amp?

Did the shop you borrowed it from have the same problem? Are you going to track down another one to listen to?

The INT-25 has been returned. It was just not working correctly. I truly tried everything I could think of to make it work, but I'm sure there's something wrong with the gain stage of the amp. With efficient speakers, I shouldn't be able to say in the room with full output of the INT-25, yet I barely hit 90dB at that point. DAC was set at full output (tried both fixed full output at 96, which is max, and variable output which then goes to 100, both set to High output) and nothing... Tried a phono stage (Andover SpinStage) which has an output of 71dB with the Shelter 501 (according to Andover, hence for most applications, I use inline attenuators which I removed for testing of the INT-25), but even with this I couldn't get the volume much more than 90dB at full output.

I spoke to Pass Labs and they're just as stumped as I was as to why it doesn't get loud enough.

I also think this is the root cause why I was so indecisive with this amp to start with... loved certain things about it, but it was lacking something. Bet that was the super low gain in the front end of it...

Try Lavardin.  Detailed, but rich tube like sound.

I recommend a Prima Luna tube integrated. It’s the easiest way to own tubes, and they sound amazing. You can roll tubes easily without worrying about biasing or flimsy tube sockets. You can choose the tubes that work best for your speakers. If you want the most functionality, go for a PL EVO 300 or 400 integrated. I have a little EVO 100 integrated in my second system, and I’m running a set of TungSol 6550’s to drive GoldenEar Triton 1’s. AMAZING midrange, clarity, and a soft, beautiful top end. The bass drivers in this speaker are powered, so I don’t need to tax the amp that much. Your speakers are pretty efficient, so a PL EVO 100 may be all you need. I love PrimaLuna. I have an EVO 400 pre-amp hooked up to Pass Labs XA 60.8’s in my main system, and I’m driving Dynaudio Confidence 20’s with a Dynaudio Sub 6. It sounds great! PL and Pass make an amazing combo, and I can listen to this system for hours and hours. No fatigue. By the way, I would recommend staying away from ARC products. I’ve had 5 of them, and they were all flimsy, noisy, and terribly overpriced. The best ARC product I had was an old VSi60; it was built like a tank. However, even this amp had a problem with the mute function. It was annoying. But I digress. Make it easy on yourself. Enjoy the music. Contact the folks at Upscale Audio, and they will get you all set. Cheers!

For less than the cost of the 25 integrated just add a Schiit Freya + to the XA-25...you'll get more of everything (inputs, outputs, tubes, no tubes, etc.). I use an original Freya with mine (XA-25) and the resulting sound is killer. Gain a-plenty.

Let me throw in the Don Sachs Valhalla tube integrated as a possibility. I had the Linear Tube Audio z40+ integrated which is more expensive than the Valhalla and I thought the Valhalla was significantly better. It has about 33 watts per channel (you can use 6L6s, KT-66s, KT-77s or EL-34s and it is auto-biasing with a meter to check the bias of each power tube easily in front). It has one balanced set of inputs and a nice remote. I've had one for a few years and love it. It is lush, fast, detailed and adds detail and bass that my previous tube integrateds (the LTA and Rogers) couldn't match. 

I spoke to Lynn Olson at Pacific Audio Fest a few years ago who told me that the Valhalla, in his opinion, was as good as integrateds costing three times its price. Additionally, even though the Valhalla has 33 watts per channel, it easily drove 4 ohm speakers with 88db efficiency in the hotel room it was in. 

http://www.dsachsconsulting.com/valhalla%20integrated.html

Sorry bout dat.  Wouldn’t be the first time I was thinking ass backwards.  Still think it’s a gain problem though.

I heard a Ayre AX5 Twenty a few years ago and it was really nice, so that might be an option. Didn’t even thing about that.

The AX-5 Twenty is an end-game quality integrated. Lower noise floor than the INT-25 and noise floor matters considerably. 

@marco1 the INT-25 is single ended, so no way to use balanced output from the DAC into the amp. Using RCA adapters negates the additional 6dB output.

@helomech I heard a Ayre AX5 Twenty a few years ago and it was really nice, so that might be an option. Didn’t even thing about that.

Try an Ayre.

Ayre sounds nothing like Luxman or Pass Labs, so weird that Luxman was suggested as an alternative in the same post.

My Ayre V-X5E sounds almost identical to the Pass XA25 but just a tad warmer and with greater headroom and bass. 

Try using XLR outs from the DirectStream (with RCA adaptors) to INT-25.  Per PS Audio that will give you 6db more gain.

I’m quite sure you have a gain problem with your source.  I had the same problem with an INT-60.  Would have to turn volume knob up to almost 60 to get volume barely past conversational levels.  Once I changed the source to something with more gain, the problem went away.

Whoa! Just tapping into this thread now and, as a Pass INT-25 owner, I would concur with the others who suggest that there could be a technical issue with your amp. Or an issue with the output of your digital front end. I have Devore O/93 speakers (at 93dB spec, much less sensitive than yours) and it'd be a rare occasion that I would ever get up to or past 50 volume with a feed from my Roon Nucleus -> Ayre QB-9 Twenty -> INT-25 playing any genre of music (and I like things loud for both rock and orchestral). And when I'm spinning vinyl with my Sota Sapphire TT & ModWright PH9.0XT providing the feed, the gain is even more significant into the Pass and 'quite loud' in my medium size room would be 40-45 on the volume setting.

Have that amp checked out. And if no issue with it's output, it's got to be a source feed problem (IMHO)

Although you haven't mentioned the size of your room and distance from speakers to listening spot, unless I missed it (?)

@bjesien 1 watt should give you 96db near the speaker so should hardly be conversational at the level you are setting it. Something is off.

Mute button on somewhere, lol.

I went to a bar in Colorado and the sign read: liquor in the front poker in the rear. Point is we don't want to mess these things up. Well stated Thompson.

• Typical distance from rear wall: 2-4′ (60-120cm)

Personal rant: The wall behind the speakers is the FRONT WALL. It's the wall in FRONT of the listener but behind the speakers. If this is the back wall then what is the wall behind the listener. the "other" back wall?

Just a personal pet peeve, carry on!

1 watt should give you 96db near the speaker so should hardly be conversational at the level you are setting it. Something is off. 

Volume is set as fixed for the AirLens (and in Roon) and the PS Audio DirectStream is set as fixed, high, 96 (which is max). Everything is at full blast into the amp, yet at almost full output of the INT-25 is barely above conversational level.

Sounds like an amp issue. Did you even control the volume from your dac or via Roon or something is turned way down (DSP)?

The impedance curve is a range, like a set of stairs that the amp had to walk constantly. Nominal doesn’t mean much for a speaker load especially when talking lower powered tube amps.

You are making progress

Yes, there must be something wrong with your amp.  The sound should be extremely loud at 50 on the INT-25 with PAP Trio speakers.  I'm curious to hear what the tech says when they look at it.  

I may have discovered why this INT-25 is not working well... to get to a volume that's about conversational, I need to turn the volume up to 50 (the volume goes to 63). I borrowed a new INT-25 from my local dealer (their tech is out, otherwise he could've looked at it) and on that unit at about 30 it was quite a bit louder than conversational.

Could it be that I simply struggle with the amp because of a gain issue?!

The necessity to have a dealer or technician bias tubes in the Audio Research I-50 is a large negative to some of us.

I am running an http://www.triodelab.com/ 2A3EVO amp and really love it, my speakers are 97db efficient which is equivalent to PAP Trio. The mid range is magical and it has a nice quick/tight bass. I don't listen loud. I have had it for 2 years and it is the first amp I have had where I have no desire to change, yet....

I was trading emails with Ze'ev (PAP owner) and he said he uses a 2A3 Set amp as part of voicing the speaker.

I am considering the same speaker with the horn when finances allow.

Good Luck

https://pureaudioproject.com/classic15-open-baffle-speakers-by-pureaudioproject/

Scroll all the way down to the end of the page and you'll find:

MORE TECHNICAL DATA

• True Point Source D’appolito Design
• Sensitivity > 96db (in a typical room).
• Nominal Impedance: 8ohm.
• Frequency Range: 29-32hz to 20Khz (in a typical room).
• Drivers: see above: About Trio15 Components.
• Crossovers: see above: About Trio15 Components.
• Typical distance from rear wall: 2-4′ (60-120cm)
• Distance from side walls: Any
• Size: W:54cm H:125cm D:27cm | W:21.25″ H:49.4″ D:10.63″
•  

• Weight: starts at 55lb/25kg

 @bluethinker thanks for posting about the I-50. I owned a VSI-55 about 15 years ago and was wondering about the I-50. Does anyone know what's been done to "upgrade" this amp to the newest addition? 

I found the VSI a little cool, perhaps the Op did too if he's moved on.

I don't see an impedance curve on the Pure Audio site. Anyone that claims high efficiency in my mind should post such information. Instead they say "effortless and dynamic sonic performances with any amplification." That's usually misleading an expensive for people to find, but maybe I missed this information.

Keep us posted good thread.

@audiojan - Over the last five years I’ve tried to listen to as many amps as possible. One amp that stands out in my mind is the Audio Research I-50. I originally ordered one when we were first coming out of COVID. Unfortunately, supply chains were slowing things down so I cancelled.

And I regret it! 

The I-50 was gorgeous sounding. And it had just that touch of warmth you are seeking. Based on your description, I suspect it’s exactly what you are looking for.

@audiojan ..." these the most neutral, detailed, yet smooth cables I've tried."

Yep.  Exactly what the INT-25 is showing you more of too. More neutral, more detail, less bloom.  And so it goes.   

@audiojan What happened to your Diablo 300 and W/P 8’s?

Might want to check out the Roger’s High Fidelity 65 V - 2 tube integrated. Superior build quality, lifetime warranty & sounds great if powerful enough for you. 

I'm pretty set on keeping my Silversmith Fidelium cables. Of all the cables I've tried over the years (and they're quite a few and almost all more expensive than the Silversmith's), these the most neutral, detailed, yet smooth cables I've tried.

Same goes for the digital front end. Replacing the PS Audio DirectStream Sr (with multiple modifications) would cost way more than replacing the amp.

Also, I'm not going back to separates again. I've had some many over the years and the simplicity of an integrated is getting more appealing the older I get.

So I'm either going to stay with the INT-25 (and there's a lot that I love about it!) or I'm going to a tube integrated (and there's a lot I love about tubes).

I do appreciate all the input and options offered up.

Have you considered the Sugden A21 SE? Less expensive than the Pass, but some reviewers prefer it to the INT-25; slightly larger soundstage. I think you'll find a slightly warmer sound, as well. Voices are lovely.

While I have almost no experience with PrimaLuna, they have at least 4 different, all tube integrated amplifiers you can check out.  With tube rolling, you could customize the sound to one that makes you happy.

All the best.

To @audiojan did you happen to notice the other cable thread and questions going on right now, one member posted something similar about your same SilverSmith Fidelium cables?

I’d recommend you message this member [@sls883] and ask more and why they changed to something else, our what changed since.  Maybe worth checking into this more potentially, look here:

https://forum.audiogon.com/posts/2766914

To @audiojan its not that we believe your INT-25 could not work, but we all have been in a situation where the sound was too much in one way or another and lacking in other areas compared to our "last" system setup, for example. Then we find ourselves fine tuning in other areas upstream, like changing DACs or (sure enough) trying different cables again etc. It’s kind of a balancing act to get there.

I had a pair of these popular [other brand] OCC cables once that were so open, transparent, huge sound stage, and simply were not as engaging, and for my taste they were a bad match for one of my amplifier setups. Went back to simple pure copper ICs and speaker cables I had before. All the sudden things settled down, quite a bit actually. The midrange music was back again. Two other buddies had the same cables, same issue, all of us resold them. It happens some times with different setups. Some cables I've tried can cause situations like this too, fwiw.  

A few last thoughts, free to try fwiw:

• Warmup: As a quick test, can you leave your INT-25 powered on for 48hrs, particularly so if it’s been sitting cold in a box somewhere and before you received it? No joke, I had recently rotated my older Pass/Forte’ amp back in recently and it had been out of rotation for six (6) months. First try was not smooth, grainy, too etched. Left it on for a few days, went back and listed again, and a very nice change on the first startup back into the system. Better every time since. That’s one things to try.
• Toe-in: Are your PAPs toed in quite a bit now? Can you try to toe them back out almost straight forward for a bit, listen for a while, see how it goes, then slightly toe-in again if needed at all, or none.
• Cables: do you have a local shop you can borrow any other less open/airy ICs going between your main device/DAC etc to your INT-25?

Best of luck, just a few thoughts before you jump ship to a tube integrated. This whole thread has me thinking too what my next consolidation move might be btw.

I definitely like the options having a Pass Preamp with the Sit-4…maybe it’s me but having separates is really nice…the Sit-4 really sounds nice with my horn speakers. I had a lot of tube gear in the past with lots of problems with the Primaluna gear. I always missed tubes so just yesterday I put in the Modwright Analog Bridge and it definitely changed the tone for the better, I slammed all the most harsh sounding fingers on a chalkboard electronic music through it and wow it took enough of that harshness away so I didn’t leave the room..one song I love is from Duran Duran Ordinary World it took that song and gave it a nice sweet tone..

I also have the XA-25, love the Sit-4 more…if you have to go all tubes play it safe and get the Cary Audio SLP-80…

Looks like the consensus is try a tube integrated. :-) I was hoping that the INT-25 would bridge the gap between solid state and tubes, but I think that was hoping for too much.

I'll look for a good tube integrated. I've had Audio Research in the past, so that's definitely an option

Someone mentioned modwright and they're a brand I would definitely look at. Their KWH225i is a hybrid integrated. I have a pre of theirs and love it. Tthe Music Room is an authorized dealer and they often have an open box for a great deal. Might be a good match

There have been some great suggestions and the cables are definitely worth looking at.  I was also in a similar situation with my very expensive SS integrated which I really enjoyed but slowly realized I missed the tube sound.  Purchased a nice tube integrated and listening with a smile on my face!

To @audiojan if I may suggest, its the combination of your INT-25, SilverSmith Fidelium cables, paired with your PAP speakers all together, exactly what and why you are hearing what you are enjoying less now if you are more into a system with warmth and body to the sound. If you truly came from a tube system, with your PAP speakers, that prior matching likely worked well together for you in a more engaging way, correct?

We see you don’t believe your new cables have anything to do with it yet I happened to catch your post on the PSAuido forum with the same handle name about how much more airy and open your new cables are compared to Cardas Clear Beyond. I'm a Cardas owner and CBs are pretty open, airy, and detailed too. So, If this is the case, detailed + detailed + revealing = more revealing detail and less of a plush sound imo. Top end is likely much more tipped up now I'd guess.

Sharing fwiw, my main system is all tube. My secondary system is a tube preamp paired with a solid state amp of Pass lineage to help keep it a bit smoother etc.

Matching & Pairing:

If I were in your shoes, I’d be chatting with every owner to be found with your same PAP Trio15 Class speakers, and inquire more about which TYPE of amp and cables they choose to pair up with most and why.

Tube integrated:

Its easy to see why many here are recommending a tube integrated to you instead. Its not that your INT-25 is not a good choice, I just believe you are hearing more of everything now and the lushness of "tube" is not there any more. Note: I sold three pairs of the older Cardas Golden Cross cables to Pass owners with similar comments as yours and what you are experiencing right now - if it helps to know. 

I'd be looking for a tube integrated to demo next and compare, decide from there. 

@audiojan are you open to "tube" integrated options?

I read about the Modwright Analog Bridge. Tubes and you just put in your system before the Pass and its supposed to add the tube warmth. No amplification. Granted I've never tried it but I'm curious so maybe someone here has heard it. I also have Pass amps btw.

I’d just go for the VSI 75.  Straight forward easy to bias. Love mine.

Have you seen Steve Guttenberg's reviews on his Audiophiliac youtube channel?  Steve has PAP Duos as his reference speaker and has compared several Pass amps, Linear Tube Audio amps and other amps.   The LTA ZOTL Ultralinear+ Integrated might be worth a try. 

@ghdprentice @yogiboy doesn’t the I-50 require a technician to bias the unit when tubes are replaced?  I was seriously interested in this integrated as a first foray into tubes but this was the main reason I shelved the idea.  Maybe it’s not a big deal or doesn’t matter to the OP but it sounded like a pita to me.  I was really disappointed to learn this about it.