Pass Labs XA25 without preamp (from a variable output source) vs INT25



I just have a single source system (a DAC with a high quality variable output) so what would be the best aounding option? DAC direct to XA25 through the variable output or DAC with fixed output and an INT25?

Reading between lines it seems INT25 looses some transparency and gravitates to a warm sound compared to the very clean and transparent sound the XA25 provides. I love a transparent, rich and 3D sound but I don't want a lean sound. 

Anyone here uses the XA25 without preamp from a high quality variable output source?







I knew that thread. I have searching but I have very little info about using the XA25 without preamp. I´d love to hear from someone who tried the XA25 this way.

Thanks again!

I'm trying it now. It works really well and is sounding excellent. Volume control via Apple Music for me.

Have you compared the sound with and without preamp? If so, could you please elaborate the differences between both ways of use?


running an xa25 with a very nice tube preamp. a solid, transparent dynamic linestage is by far the way to go for energy, blistering dynamics and soundstage.

many people grossly underestimate the contribution a top quality linestage can make.  


@joegt If you don’t need the extra gain, adding a preamp will give you extra noise, extra distortion (good or bad), less detail and separation, extra wiring, I’m sure there are others.

Going direct, if you have enough gain, and your source is low output impedance negates all of those negatives above. You "may" not like it as it "may" show up other problems a little more focused. Andy



I can't agree more!

The sound without pre will go quite flat in most situation.



Sound without a pre is only flat if your DAC has a crappy output stage. Buy a properly engineered DAC and that won't be a problem. 

Sound without a pre is only flat if your DAC has a crappy output stage. Buy a properly engineered DAC and that won’t be a problem.

+1 Most dacs today have ss output stages that are just as good if not better than your mega buck preamps, and defintetly better than tube preamps. Andy

+1. And if you want designer colouration, play around with DSP. Most audiophiles would turn their noses up at something like this:

But I dare them to try it



My Experience- I had the XA25 with no Preamp-Ran thru the Oppo 205.

Loved it and shopped preamps with a tube. Decided the INT25-designed

to mate with each other-might be wisest so I moved up to the INT25.

I never felt the SQ improved with this move however.  I Added an AudioMirror

R2R DAC (with tubes) and fell in love again.

Bottom line- Use the XA25 sans pre if you can do it. 

Sorry I can not elaborate the differences as I sold one before receiving the 

other. (Rookie mistake)

@avanti1960 Have you tried to drive the XA25 directly bypassing the Cary in yor system? I´d love to hear your comments if you try it. BTW I owned a SLP98 many years ago driving Cary 300SE monoblocks. Nice preamp but with awful sounding signal caps inside (oil1 caps). I replaced them with Hovland Musicaos and the sound improved tremendously in every possible area (transparency, detail, timbre, soundstage, bass control, etc)



UPDATE: Ok, I listened for about an hour. I think the preamp is needed. (Mine is in the shop.) Why? The dimensionality of the soundstage is much reduced and there is a raw quality to some of the recordings where before there was a smoother and more liquid quality.

In short: I retract my earlier claim that it sounds good. With my relatively inexpensive streamer (but nice DAC), I still want my tube preamp back.

Also, it couldn't play above about 78 db.

@chorus Thanks for sharing your experiences. 🙂 When you replaced your XA-25 for the INT25 you say you didn´t notice a SQ improvement but, did you feel you loosed "something" with that move? Which speaker do you have?


@hilde45 Thanks for the update! Much appreciated!

Just noe more question. Did you use the same DAC when using the XA25 with and without the preamp?

BTW it´s not a surprise you only get 78dB cause XA25 has only 20dB of gain so if droven directly by a source and without a preamp that source must be one with more than the 2V CD standard voltage.


Thanks again!

@joegt Yes, same DAC. 

My setup is BlueSound Node 2i --> Orchid DAC --> XA25

Honestly, I *wanted* to like it. I hoped I had found a magical way to cut out the preamp. Here's what a friend said about my experiment:

"you lose some layering not going through a tube amp. I’d expect it to be a tad more grainy, less depth, and not as smooth....An active preamp is one of THE most important components ina lower efficiency system. Using a Node’s preamp section and volume control is gonna be limiting. An XA-25 would reveal all limitations of a directly connected source like (the preamp section) of a Node2i."

@hilde45 Did you control de output level of the Orchid DAC with the Bluesound? If so then I think you are loosing bit depth resolution performing attenuation in the digital stream instead at the core of the DAC (modern DAC perform digital attenuation at much bit depth inside the DAC). If the Bluesound has a modern DAC (i.e. ESS or AKM) that performs digital attenuation at DAC core and at much higher bit depth I suggest you to try the variable output of the Bluesound directly to the XA25 and please share your impressions with us. Althougn maybe is a lower quality DAC than the Orchid I think you´ll have way better results this way if variable output is used.




P.S.: SOrry about my Englis grammar. I´m not english native spoken.

I can try the Bluesound.

The Orchid cannot vary the volume.



hi, i have never tried the xa25 without a preamp but i have gone the passive preamp route before and did not care for the sound vs. a dynamic energetic preamp.  

btw i have the cary slp 05, not the 98.  

sounds just burst and project into the room lively and without strain.  no DAC that i have heard or even many linestages can compete.  expensive yes but hearing is experiencing. shortcuts are just that, they can sound fine until you hear something else.  

joeyg- My speakers are Tannoy FSM (monitors) from the late 80's.

That is the million dollar question. When the new INT arrived it needed

200-300 hours of burn in time so at first it was worse. My audio mentor friend

loves it as do I so all I can say with any certainty is what I stated- no improvement.

The Preamp section is said by the Pass people to be "Minimally invasive".

True enough as it has no Pre-out, no sub out. One output & 3 inputs.

@avanti1960 I used extensively passive preamps in the past too (some Audio Synthesis units)  but that is a much more complicated way to achieve nice results than using just a source with high quality variable output into an amp.

With a passive preamp between source and amp you must take seriously some considerations like having a low source output impedance, a low cable capacitance and a high input impedance of the amp (and of course high output and an amp with hig sensitivity). It´s very easy to have a mismatch and get a poor sound with a system with a passive preamp. So unless everything is on set it´s better to avoid using passive preamps.

Getting nice results with a source driven directly an amp is way much easier so if you´ve got bad experiences with passive preamps in the past I strongly suggest to not extrapolate that experiences and  give the "source direct to amp" way a chance, may you´ll like the results.


I´d like to say that I´d love to hear that going direct to XA25 route brings spectacular results but I have my worries. A more transparent and pure sound? I´m sure. A "leaner" (cleaner) sound than with a preamp? Of course but as I´ve said I don´t want to get an overall lean sound so here my interest to hear from anyone that have tried both ways with this amp.

I did DAC With digital volume control direct to XA25 and enjoyed it a lot.  But adding a tube preamp did bring more lively and saturated tone and 3D space.

preamps are also very good at integrating multiple sources :)