Pass-Labs break-in


Per your experience, how many hours the Pass-Labs XA160.8 monoblocks need for break-in?


I do not have XAs, but for all of my Pass gear over the years, I stopped thinking about what I was hearing after about 150-250 hours. Those who claim 24-48 hours are, IMO and IME, off base, and those who claim multiple hundreds of hours are equally off base.


Haven’t owned the XA160s. Have owned the X250-5. Little if any. It’s always tempting to hear break-in in a new component. I heard none to be honest. The big Pass amps, class-A or A/B run pretty hot. Be sure to give your amps lots of time to completely stabilize before any critical listening so you don’t confuse warm-up with ‘break-in’. I turn mine on first thing in the morning and let it cook if I’m going to be listening critically that day.
Happy listening. Pass always delivers the sonic goods.

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@Baldy can help with this one. He has XA160.8’s

Every Pass amp or preamp (a lot of them!) I’ve owned has been left on for at least one week before I first listened critically.
After that, the amps sounds noticeably different after an hour’s warm-up.
It’s a happy ritual.


When my friend bought his X250.5, at that point in our lives I was living three hours away from him. A day and a half after he got it, he called me and surprised me with his purchase news. My response was “I’m on my way!” Three hours later I got there and we sat and listened long into the night. There was a point where suddenly, we both heard a shift in the sound and looked at each other in shock. It had gone from good to great. We both heard the same thing at the same time. The total time on the unit at that point was probably only about 20 hours. I drove home in the wee hours of the morning, after which he would provide me with details of changes over further time (those were much more subtle).

I would say “I didn’t care what I was hearing” anymore from my X260.8 monos after maybe a little less than 150 hours. My recently received XP-22? Granted, not an amp, but the “leave it on for 24-48 hours and it’ll be good to go” recommendation was hogwash. After two days running 24/7 it still had a raw quality to it. After close to 250 hours I felt it was as done as I could hear it. Afterward I called Pass to ask them a question, and happened to speak with Desmond. Since I was curious, I asked him what he felt about the preamp burn in time. He felt that two weeks solid running 24/7 would get things “90-95%” of the way there. That’s about as close to expert confirmation as I’m happy to have gotten. I never did ask him about amps, though.

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Thank you, everyone.


They take an hour or so to come to temperature and then the magic happens.

I bought mine as dealer demos so unsure of the actual time on them before I owned them.

Pass also recommended just using the stock power cords and no line conditioner but I used my trusty BJC / Iconoclast PC’s and my P20’s for incoming power.

Unfortunately all of my stereo gear is in the warehouse for a few more months


The XA’s have been powered-on (no signal) 24/7 for the past 5 days. Today’s the first time listening to them (as a context, I’ve had BHK 300’s for the past 2.5 years).

So far, the XA’s sound somewhat congested, with limited dimensionality and airiness to the soundstage.

Given the accolades these amps receive, suspending judgment until more break-in occurs is key.

Warehouse? You must not know of my free audio gear storage!


Odd that you would be experiencing a lack of air, dimensionality and a degree of congestion with the Pass Labs XA-25 amplifier. My experience is that this is where they excel, especially providing a sense of inner detail. My preamp is a Threshold FET Ten H/L, interconnects are Iconoclast RCA Ohno, and speaker cables are Discovery Essential, bi-wired. Speakers are 96dB efficient open baffle Pure Audio Project Trio 15 Classics with Voxativ PiFe Full Range drivers. Refresh my memory as to what are the companion components, such as preamp, speakers, and wires. Yes, it could be they need more break-in. With time that amplifier should settle in nicely. My experience with break-in is to play a combination of music and white noise continuously, for several days, then give a listen. Usually additional break-in is needed for as much as two weeks. I have several FM tuners on hand and typically put them to work as a source for amp/preamp/speaker break-in.

Indeed, I was slightly surprised as well. At the same time, I hold in mind Pass-Labs’ and XA160.8’s are top-notch components (independent of one’s subjective preferences), therefore needing to allow it to fully bloom.

The amps were powered-on without music over the past five days (~100 hours). I will certainly follow the advice on playing white noise & music for the next several days, in hope it start manifesting the liquidity, details, and realism so frequently associated with Class-A.

Components and cables:

  • P20 (though the XA’s overloaded it when both connected), Oppo BDP-103 transport, DS-DAC MK2, BHK pre-amp, Aspens FR30, REL S/812 (pair).
  • AQ Thunders to P20 and XA’s, AQ Firebird HDMI, AQ Earth XLR interconnects, AQ William-Tell Zero & Bass speaker cable (bi-wire).

XA 160.8 owner here.

Are they being supplied by the P20 or are they now plugged directly into the wall, given the load they put on the P20? If you’re using a regen or power conditioning, my suggestion would be trying them plugged directly into the wall outlets.

I run mine direct to the wall. My experience has been that the bigger Pass amps do better that way, especially with respect to “congestion.”


Directly to the wall, with AQ Thunders.

I should have you come over and catalog the lot so I can weed out the pieces no longer needed or wanted.
It looks like a hoarders stereo collection at the moment.


Looks like or is?

There’s nothing wrong with that! My kind of people!


Well if a stereo hoarder looks at the pile they will be fine. Maybe even a tinge of jealousy.

If not then they would suggest an episode of the TV series.


You got that right. Not an intervention, just a justification to “weed and feed” to clear out the old for the new.

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Baldy Hording is a serious mental condition, I suggest you let me come over and clean up the mess for you thereby saving you hundreds of hours of expensive therapy :slight_smile:

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