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

Though there are perhaps better transistor amps, but Pass seems to be an excellent choice for many.
What is your experience with them, if you could elaborate ? Integrateds as well.
Expensive, Big,run hot also cost a lot to run, forget Solid State, have a listen to a Nord Acoustic mk11 class D with the REV D upgrades, you can choose various OP-AMPS depending on ones taste or system, you can buy all the various OP-AMPS and find which ones suite your taste its called OP-AMP rolling,

Phone Colin he sells direct worldwide and prices are very reasonable, my Nord One UP SE NC500MB mk11 costs approx £2000 and sounds amazing no faults at all, its xlr only, 

Then find yourself a good pre-amp with the money you saved I recommend Townshend Audio  Allegri + no need for expensive power cord or conditioner, no mains noise, its single ended only, i use Cardas Clear female rca - male xlr the combo sounds incredible for £4500 

Check out the review of Allegri + in Positive Feedback and Nord Acoustic stereo amplifier in HIFI PIG and Six Moons 
I do not know Troy and have never shopped in his store. I enjoy his posts. While he certainly has some motive to promote the brands he sells, his thorough and knowledgeable insights allow me to learn about large, heavy and expensive gear w/o having to buy (and sell) everything out there. I purchase from (the few remaining) brick and mortar stores locally as well as from retailers and private sellers on A-Gon. I do not post very often these days, but do read many of the A-Gon threads. At 61, & with a bad heart, my audio addiction has become more difficult to feed. I no longer find it at all easy to transport, unbox, set-up, re-box and ship large and heavy equipment. Thanks to Troy and others who post and provide insight to the fine Audio gear that is becoming more and more difficult to hear in stores and audition at home.

I have owned different Pass power amps and mono amps. I had contact with Desmond Harrington (President of Pass Labs) for a long time. I also owned the XP-20. It is a good preamp, but not a stunning one.

When you judge Pass Labs on all the aspects/properties of sound. It will become clear that they lack realism in the individual focus of voices and instruments. When you listen to voices and instruments in real they are very small and direct. The Pass Labs preamp and power amp are not able to create the intimate focus as in real.

Desmond told me that the 0.8 series make voices and instruments smaller and more palpable. But it is still not among the best. In my world, it is only about the best possible. The rest is 100% useless in my world.

Voices and instruments are not only very small and direct. In real you can even hear the shape of a voice and instrument. I call it a High End ++ property. When you judge Pass Labs on this, it shows that it cannot reveal this part.

When I was in Munich at the High-End show in 2015, only one system of over 700.000 euro who was able to reveal a 3D shape of voices and instruments. The problem in audio is that most people who work in this world or see it as their hobby know very little about sound and music. Even most manufacturers have very limited knowledge and insight in sound in general.

When I talk with them about the acoustics, electro-smog, high-frequency noise and magnetism they still know very little. It becomes clear why so many audio brands and products are still sound so different than music sounds in real.

You need to understand all the aspects that influence both sound and stage. Sound is very complex and can only be understood and guided when you understand the influence of all these aspects. In all other situations, you still do audio by trial&error. This will always be audio without any real foundation. It can only create audio systems that miss essential parts of sound with also many flaws.


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.