What are the weak points of Pass amps and pre-amps ?

@bo1972 

So here is the thing.  Even when talking about the "realism" of instruments.  

I would make the argument that anything amplified - ultimately doesn't have much "3d" sound.  Electric Guitar/Bass in particular.   Anytime you are at a concert which is amplified, regardless of genre it doesn't matter.  It's being pushed through amps firing in one direction, fed to a PA system.

Now, a small venue, piano, acoustic instruments, horns, etc.. Unamplified music, a singer in a small venue etc.  I can buy some 3d realism to that.  But, the soundwaves are still subject to the space they are in.  But take out the amp/PA system I do think there is some 3d realism to acoustic instuments.

An amp - really just sends along the signal recorded.  Now do some amps add some bloom - sure, but it's just sending along the signal it receives. I will grant that very, very few amps truly are neutral.

But for 3d realism, I would argue that the source (recording and whatever is passing that along), along with the speakers and the room they are in that make the biggest difference in any 3d illusion given. Obviously, the pre-amp and amp CAN flavor that, but really what you are looking for is a tremendous source, a pre and amp that impart nothing, and killer speakers and a killer room.

Now, a killer recording can help you imagine where the individual players are in a given recording.  We all find that cool.

So, not sure if this has much to do with Pass strengths or weaknesses.  Just decided to start typing some thoughts on this... I'm on record liking my Pass Amp and do not think it's dead neutral.  I do however really like it.

I have done thousands of tests in audio in over 20 years of time. I also compared many amps with each other. In stage depth, width and height the differences are huge.

A friend of mine had a concert room with a Steinway wing. I loved the intimate presentation of both voices and instruments during these concerts. It has become an important part of our Tru-Fi. Acoustic recordings need to give the same feeling.

With our Statement Audio Pro-measurement, we can come so much closer to the live experiences I had. It limits the influences of the room and gives access to a superior level in detail and layers of each recording.

Each part in any system owns it’s DNA. I did spend thousands of hours and tests in over 20 years of time to be able to reveal the full DNA of each individual part of an audio system. I have been working in audio full time over 20 years of time now.

Working by Tru-Fi you can create a superior level in realism and emotion compared to any trial&error created system. When we let new clients hear a Tru-Fi system, they understand often after a few sounds how limited their own system is.

The differences are created by the superior level in emotion. Emotion is the only key and way to success in audio. That is why an audio system needs to reveal all the details and layers of the recording. We always ask new clients to bring in their own music they know best.

Then it is very easy to feel and hear that Tru-Fi overrules their incomplete and limited trial&error system. The biggest problem in audio is that almost all brands and products cannot reveal all the aspects of sound. This means that these products will always create a lower level of emotion.

Only those systems who are able to reveal all the details and layers of a recording can create an emotional and addictive sound. Most people own incomplete audio systems with acoustic limitations. This will often keep them from buying new music each week.

In over 20 years of time, I visited hundreds of people with serious systems. I was often surprised by how little music they have. Trial&error will never make them understand what they change in their system. They focus a lot more on the sound and stage of their system. Trial&error will often limit people from listening to their music. The fact that they often have little music proves it.

Inna, I have a Pass Labs XA30.8 amp and a Pass Labs XP-20 preamp. They are great. The amp is a bit heavy 100 lbs, being class A it puts out a little heat. I don’t run my amp 24/7. 1 hr warmup is all that’s required for excellent sonics. I have no negatives for the Pass Labs XP-20. As with all equipment I would say ~ 500 hrs breakin to hear the “real deal”

THE meter is useless and you're paying for it anyway. The speaker "wing" connectors on Pass and many other top brands can make it difficult to connect heavy speaker wire with spade lugs. If you don't get the XS series with outboard power supplies you're not getting everything the company has been able to achieve. Any preamp or integrated amp without at least ONE tape loop (IOW a fixed-level output jack) is off my list of versatility. Also one must consider whether or not you can listen to headphones or not, even with an external headphone amp. As for X or XA, it's certainly a conundrum that makes you choose one or the other, and if you're not happy after 3 months or ? months with the sound, you're going to give yourself an "ulcer" thinking you made the wrong choice, making the hobby even MORE complicated than it is already.
My dad had a Blaupunkt TUBE radio many years ago that sounded so sweet and smooth
in spite of its limited power, etc. that a lot of people here may not have ever experienced. So it pays to understand just what solid-state is up against if you want to evaluate what's possible. Having said all that, Pass is a good fit for most audio "fanatics" and should satisfy most of us that can afford something they make. Not all speakers are a good fit for a Pass amp , but that would not be an excessively long list. My main beef with ANY product is limited connectivity, whether it's a reel-to-reel or wire, headphones, a subwoofer, whatever you need it to do.
Lastly, some components looked good 20 years ago and they still look great today (ex. a Lin turntable). Facel-lifts, meters, gadgets, are extraneous (ex.Krell) and the cost is passed on to the customer. The "old" yellow-and-black Rolls that Arther had looked better than the ones they're making now. Just making a point. 

@bo1972 

I've never heard of Tru-Fi, is this a company, something you sell/rep work for?  Just never heard of it.