Can I wait that long? Maybe. I do want to get the PMG DAC too, so I have to figure out how to do this without upsetting the finances to much …
I’m not a measurement fanatic, yet if the post break-in audible bass is either deeper or higher in amplitude, it should be easily measurable. I’m happy to consider contrary arguments.
I am a believer in break in improvements. I have a system that costs more than my house. I have never once had any interest at all in how it measures. There is a specific forum for measurement people. I imagine you like it. I have zero interest in it. Ears are all that matter.
This is not an accurate way to determine if the amplifier has left class A or not. AC Line fluctuations can still happen with class A amplifiers.
Trying to decide whether to go s200, 400 or pass xa25 for my fr10s. If anyone has any experience with the pass or ( in the unlikely event ) have heard both amp offerings from pass and ps audio , any recommendations would be greatly appreciated
Based upon my short experience now with the S200 and FR20’s, I believe you will be pleased with pairing the S200 with FR10’s.
I hope this informs to some degree: I have the FR30, however, no experience with the PMG amplifiers. I had the BHK300’s monos and BHK preamp for several years, later shifted to Pass-Labs XA160.8 monos and XP-32 preamp. As further context, digital sources only, previously DS-MK2 and currently PMG512 DACs.
To my subjective ears, the Pass XA’s are significantly more ‘organic’, controlled, and embracing in their sound than the PS BHK’s. The BHK’s are more ‘exciting’ with sharper edges while the Pass are more ‘embracing’ with richer tonality, provide a darker ‘canvas’ upon which sonic details cohesively appear, and exceptional sense of realism to both human voice and instruments exist.
The BHK’s seem to have greater separation among instruments, however, at the expense of sometimes being slightly too forceful in making you notice the separation, while the Pass present it to you when relevant and naturally occurring in the recording.
Measurement can show serious design flaws, less common these days than in the early high end audio era. Still there are a few turkeys out there. By all means, listening is the meaningful determining factor.
A general comment on my comments on burn in. I am a retired scientist trained in the old school which does not go by “trust but verify” but rather: doubt but test. The way science at least should work is that you advance a hypothesis and then try your hardest to disprove it. Why the negative approach? Simply put in science we can never “prove” anything. We work with and use hypotheses that have survived testing and we give our testing methods rigorous scrutiny. That is why I reject auditory comparisons that span 10’s and even 100’s of hours. Our aural memory is just not that good over such a span. So what test could we use? adifferentpaul posted a potentially useful test-compare two pieces of the same gear, one brand new, the other with some use time. He perceived a difference. But here is where my science background kicks in: did the two pieces of gear sound the same before one was burned in? was the listening experience double blind? was everything else exactly the same, cables, outlet plugged into, even position of the gear, was the recent use history the same, were they both cold or had one been running and the “new” one substituted cold? None of these questions should be taken as an attack on adifferentpaul (let’s call him “adp”. It just what scientists do (except those who dedicate their careers to winning the Nobel).
Now in the end, I fail to see why the validity of equipment burn in is relevant. Our evaluation of our gear and changes to it should span more than a mere glimpse. The gear may change, yes, but the hypothesis that our auditory perception varies has lots of positive testing. And based upon the widely held belief that burn in always results in improvement, if your new gear sounds better upon initial installation, keep it as it should only get better.
Skip the Pass Labs XA-25, as it will be underpowered for the FR-10 speakers. The S200 is a logical choice.
Wait, so you are endorsing PS Audio gear after all? What is the world coming to? 
Funny guy. Their gear can sound great, and they have come into their own with the PMG amplifiers and preamplifiers. Regarding their digital projects, I prefer other gear for the sound and reliability. Personally I’ll take a Pass amplifier and preamplifier. As I have stated before, of all the gear I have owned over 55 years the only gear I have ever had reliability problems with is PS Audio.
Good to see that you recognize the fact that audio gear needs to be plugged in for a length of time in order for it to reach its optimal operating temperature, and sound its best.
Just curious how you reached that conclusion. Using your ears, or measurements?
No data, just the scientist advancing issues that need to be addressed before the stated experiment can be part of the data used to advance the idea of burn in to being a working hypothesis. And the scientist kicking in again: why would you presume gear sounds better after warm up? I will again advance the suggestion that some of these presumptions stem from the “old” days of new cars when you were told to baby a new car for a few hundred miles and expect better mileage after the tight rings got a chance to wear in. And sure, the our car runs better after it’s warmed up, doesn’t it?
Because it does. I unplug my system when there’s a lightening storm or I leave home for more than a few days. If listening Immediately after plugging in the system, it’s not listenable and takes at least three to four days for the internal components to reach optimal operating temperature, and sound its best.
Thank you. Now down to the s200 vs 400.
“Not listenable” for three or four days? Truly? No music for multiple days because equipment is not fully warm?
Scientist here again. Maybe it’s not the gear. One area for testing: the plugs. And your “experiment” only identifies that the system sounds better, maybe it’s just one defective component. And I am with Elk. Really “not listenable” I would start by exploring if one of my components was defective rather than assuming that audio gear in general had this property of sounding bad when cold. Never really noticed that with my car audio system in the winter.
If someone doesn’t believe in breaking or warm up that’s fine.
Scientist don’t (at least they shouldn’t) believe in concepts. Belief is the realm of religion which by its very nature is to be accepted without questioning. Science on the other hand has questioning at its core. We use the big band theory to help us understand how and why “stuff” works in the universe. And it stands until taken down by inconsistent observations. We will see if that is what happens as we explore those pesky, newly observed galaxies that seem to be too big for how young they are in the development of the universe. I will never believe in breaking in or warm up. But I might accept either or both as a working hypothesis when there are consistent experimental observations.