LSA Voyager GAN Amplifier

Jerry was able to influence the mods.

Ya think?

All I suggested is just post impressions and ignore the irrelevant. 

And how do you define "irrelevant"? Anything that conflicts with your opinion of this amp?

Really sorry to see jaymarks helpful intention...turn into a dark abyss of derision. Time to put this train-wreck to bed!!!

Sorry jerry, I didn't bring up ASR. But if I did, so what? Their review of the LSR amp is germane to this discussion. Just because you can't read and understand their technical critique of the shortcomings of this amp doesn't mean it isn't relevant. Nor does it matter if you agree or disagree with them.

Mike isn't my buddy. I don't find childish insults and mental instability attractive from anyone.

And I don't find unsubstantiated claims from audio shaman profiting off of the insecurities of others desirable either.

If you have an issue with these opinions, that's just too bad. Personally, I could say I don't think much of yours either, but that would be overstating things.

If you use a toroid coil instead of an incased coil it would sound different. 

Just to be clear, both are toroids.  The reason it might sound different might be because the inductor can play an enormous role in how the output section switches and if there are problems with it, can cause spurious noise that can be many multiples of the switching frequency. Its not the sort of thing that you play with and not also subject the amp to extensive testing afterwards to make sure it doesn't block out channel 4 on the TV or the like... I might add that the output filter caps have to be chosen for low inductance characteristics and this relates very specifically to the way the leads are terminated in the device. If you replace those parts with something different that has greater inductance, RF noise is the likely result. The module has to meet EU Directives which are pretty strict in this regard- and those directives serve as a model for the UK and China and to a lessor extent, the US and Canada. If you don't meet them the consequences can be dire for a smaller company!

So here is my question. If these Purfi equipped amplifiers are so great why is it I returned my NAD M33 after 45 days because it sounded awful?

@jerryg123 To my understanding the Purifi modules are not offered with an input buffer/gain stage. To the best of my knowledge, the buyer is expected to install their own. This is one of the reasons you see such variable comments on Bruno's modules- some buyers know how to design a proper input circuit and apparently many do not. I don't know anything about the NAD in particular, never heard it. But I do know that the input circuit has to be really neutral and there are some pretty bad examples out there wired into Bruno's modules. So if I were you I would not take your experience with the NAD as particularly meaningful.

@kuribo Sure okay.

So you are hear to save us "The Great Audio Messiah"

And I don't find unsubstantiated claims from audio shaman profiting off of the insecurities of others desirable either.

 It is none of your business.

The way I understand the NAD use of Purifi is they licensed the use of the technology, not sure they actually use Purifi boards or make their own. Perhaps if there's a photo of the inside of a NAD33 we would know. 

Thank you @atmasphere very insightful and this bears out with the Bel Canto e.One ref501S I now own that is equipped with Bruno's  Hypex's NC500 OEM module.Much better design and execution than the NAD.

I am a tube guy that has been playing in the Class D world the last 2 years.

@jerryg123 To my understanding the Purifi modules are not offered with an input buffer/gain stage. To the best of my knowledge, the buyer is expected to install their own. This is one of the reasons you see such variable comments on Bruno's modules- some buyers know how to design a proper input circuit and apparently many do not. I don't know anything about the NAD in particular, never heard it. But I do know that the input circuit has to be really neutral and there are some pretty bad examples out there wired into Bruno's modules. So if I were you I would not take your experience with the NAD as particularly meaningful.

Oh, but jerry, it is my business as I don’t enjoy the constant shilling on what is suppose to be, as I understand it, a hobby site. I don’t come here to be spammed with incessant ads and audio quackery. I haven’t attacked Ric for his opinions, I have questioned the veracity of his outlandish and unsubstantiated claims. I have criticized his business model of constantly promoting his money making "improvements" on a hobby board.

And I don’t come here to be subjected to harassment and childish insults from petulant crybabies ignorant of the technical issues who can’t handle anything but never ending praise for their (poor) audio choices.

I get it, you like the amp, you believe in audio magic. Great! Go enjoy yourself.

I am not interested in saving anyone, least of all you.

@kuribo What did you think of the amp?

@atmasphere 

Great post!

People think air core inductors are the messiah, but they can have serious consequences if not used properly. No doubt a large part of the reason for the "style" of inductor use by professional companies like Purifi/Hypex is the closed magnetic path resulting in little stray magnetic field. Drum core inductors are bad enough, and with an air core, that steel mounting screw, those resistor and capacitor leads, etc. are all now part of your circuit, let alone if a customer decides to use a steel case instead of an aluminum one, I would say very common due to the huge cost differential.

For others, the reason for not using toroids is likely for many practical reasons. To get a specific inductance and saturation point in an inductor of a given size, that requires a specific number of turns and an air gap of a specific size. That is easy with many standard cores, one leg is just ground down typically fractions of a mm. That is very difficult with a toroid, and a side effect is the gap is now exposed (EMI, etc.) For that reason and a host of others including inflexible size/mounting, gapped toroids are rarely used. Most common toroids you see in power supplies / amps (not line/audio frequency transformers) are usually a ferrous powder or some similar magnetic material molded with a binder. The "gap" is distributed throughout the toroid. The problem with these materials is they tend to be pretty lossy at the upper end of their frequency ranges and are not overly linear w.r.t inductance versus current. Some toroids are ferrite, but you are limited purely in turns ratios w.r.t. usage.

p.s. to those who called me an "armchair/wikipedia engineer", this is me having the last laugh.

the Bel Canto e.One ref501S I now own that is equipped with Bruno's  Hypex's NC500 OEM module.

@jerryg123 Just as a FWIW; that suggests that if BelCanto (fun trivia dept.: one of their staff used to work for me...) were to use the Purifi module it would sound very similar to the amp they make now.

@kuribo What did you think of the amp?

I think I have made my opinion clear here- it's a poorly designed, poorly performing, and old tech. Poorly designed because it's using bridged stereo modules and prefilter feedback, poorly performing because it's frequency response is dependent on load, and old tech because class d amp design has advanced in the last 20 years to post filter feedback enabling the amp to function independent of load.

I am not addressing the subjective performance because that, due to the load dependence, depends on what load any individual user may be using as well as any individuals personal preferences, which can neither be quantified nor disputed.

p.s. to those who called me an "armchair/wikipedia engineer", this is me having the last laugh.

Thank you for the intelligent, rationale, and reality based post. It’s refreshing to read something that actually says something meaningful rather than the "trust me" explanations all too common here. It’s also nice to see something that isn’t full of insults, posturing, and mental instability, written above a 4th grade level. Bravo!

Gee, so it seems you can't simply remove and replace important elements of the design without a thorough understanding of the component's role as a whole. Who would have thought?

I get it, you like the amp, you believe in audio magic. Great! Go enjoy yourself

No actually I was considering it and decided to play with other Pufi/GaN equipped amps before coughing up money on an unknown commodity to me (LSA).

Was enjoying the feedback fro ACTUAL OWNERS and then you came out of hibernation after a 5 year nap.

Not sure what your business is but it must be slow with all the time you are spending on this one thread. Or Wally and Ric are impacting your bottom line. Either way I could care less.

I will no longer engage you all of this is so old now. The only person who cares about your opinion is well you.

Quite the thread folks!!

Not to add any fuel to this fire, I would like to say that I have heard both the NAD & Amplifier-Dudes amps and they are not even on the same planet. Atmasphere is 100% correct about the input buffer/gain stage which is where most companies try to save money but AD has put most of his, and this is why there are some products that can benefit from modifications, and some that don't need them at all. Personally, I want to have a completely clean and neutral amplifier (to my ears) with a high SINAD to start the system, and build any flavour or character down stream, I believe that unless you start off that way you will always end up chasing your tail sonically. I also think that Bruno has done a lot to help the average audiophile with the cost/reward ratio that these modules can provide and thus allowing more funds to go towards speakers/drivers, in particular because with amps being so inexpensive, relatively speaking?? one can now think about active for a reasonable cost which intern allows for better drivers with lower distortion which ultimately ends up creating a more complete illusion with blacker blacks etc. This is the route that i'm choosing, and for me thus far it has been very satisfying. Everyone else's journey will differ, good luck with it as it's your system and your ears, i've not yet heard the LSA but will report back if I do as I've heard most of the class D options available, my amp journey, at least has ended.

Cheers,

To think I missed the whole thing. 

Mercy

I am not a robot, I'm BACK! Give me your cloths. Sarah Conner, where is Sarah Conner?

LOL

I am not a robot, I'm BACK! Give me your cloths. Sarah Conner, where is Sarah Conner?

jerry, it’s clear you don’t understand the difference between subjective opinion and objective fact, among many other things. It’s not possible to have an intelligent conversation with you, as you keep proving over and over with your incomprehensible blabbering. A lot of sound and fury, signifying nothing I am afraid. Get an education and some interpersonal relations counseling and come back when you have something civil and intelligent to add.

So long Kuribo. Bet you are ready for Hibernation.

@jaymark ,

You probably listed it, but what speakers are you using?

Sounds Great, 

Got the amp back from ASR and pluged it in and it sounds great.  He fixed the XLR

Voyager

Matrix Audio Element X DAC/ Pre ,

Blunode 2i  for Streaming Signal 

Spatial Audio X3

Generally, prefer tubes but from my failing ears, perspective it sounds pretty sweet and I enjoyed the music 

 Not the best  system in the world but love listening 

.

@cindyment I have used to different speakers on the Voyager GAN amplifier.  InitialInitiaused heavily modded Revel F208s.  About a week ago, i hooked in Spatial Audio X5s - they now have about 125 hours on them.

He fixed the XLR

Nice of him.

Chris be nice.

@jaymark , thank you for indulging me with what speaker you are using.

I don't know the Spatials other than from the web, so I can't comment too much,

I know the Revels, and was able to find an impedance curve for them. Their impedance drops below 4 ohms for most of their higher frequency performance. With the LSA, one would expect a droop/shelving of the high frequencies starting about 5KHZ, and continuing to about 1.5-2db down (roughly) at 20KHz.

If you still have pretty good high frequency hearing, and your room is "lively" i.e. not a lot of absorption/acoustic treatments, that could make the amplifier both sound less harsh to you, and by taking the emphasis off the high, give better weight to the bass. As well, though our high frequency hearing is not as good, it can present a masking function for lower frequencies, so it could, just by making this "less busy" at least to you, give a subjective impression of better midrange.

Compared to a traditional tube amplifier, based on the measurements I saw, the LSA will have far far less intermodulation distortion, and this could also make the midrange come alive for you in comparison.

I am curious what your impression are with the Spatial Audio X5s. There is no impedance data, but it is listed as 8 ohms, so I would expect it to roll off less in the highs compared to the Revel with this amp.

From a purely "state of the art" perspective, the LSA is not near the top, though I think some of the specifications, like IMD, are pretty good. I can see though, in your particular case, and compared to other products you used, why this amplifier could be the best you have experienced. I am happy that you came across it.

Did he ask?

I wish it were that simple.....that a frequency response measurement means only one thing. However......since everything makes a difference, it is not that simple. Years ago I had a speaker I had designed that had a resistor to pad the tweeter. I was using one of those junk sand resistors. When I tried to use metal film resistors there it sounded too bright and harsh. As I tweaked my system to lower its distortion I could then put the metal film resistor in and enjoy its better transparency without the brightness or harshness (that were actually coming from other parts of my system before and now were eliminated).

If I were to install Silver WBT binding posts, Rhodium plated Furutech AC socket and silver plated OFC wire in Teflon on an LSA amp you would say it is a bright sounding amp.....no matter what the load of the speaker.......because those components have that signature compared to straight wire. And this signature cannot be measured. Same with all audio wires. Some sound dull, some sound neutral and some sound bright (as well as other characteristics......mostly which CANNOT be measured). This is what I am constantly stating.....this game is really infinitely complicated. And to use just measurements is really ignorant.

Do I like the fact that the LSA shows more roll off at lower impedance loads?....no, I don’t.....nor would I design an amp that way for mass production. However, there is a person who might chime in here who has a modded LSA and before that had my modded IceEdge amp which has no roll off using lower impedances. He is using Thiel 3.7 speakers that have very low impedance and he greatly prefers the sound of the LSA amp. Do his speakers sound more rolled off with the LSA so that is why he likes it? This is what a measurement only person would say. Maybe he will chime in with his hearing impressions.

This game is an art. You must match your gear to get the sound you like. It is not an exact science like drag racing where there are just five factors: horsepower, weight, drag, traction and gearing. You can design a dragster on a computer and then put it together and it will perform down the quarter mile exactly as predicted. Audio is infinitely more crazy. Every single thing changes the sound and most things CANNOT me measured that change the sound. You must listen to really know what is real in audio.

Have a beautiful day, my sweet ones.

because those components have that signature compared to straight wire. And this signature cannot be measured. Same with all audio wires. Some sound dull, some sound neutral and some sound bright (as well as other characteristics......mostly which CANNOT be measured).

Why? What is the physical mechanism that causes a passive length of wire to have a "sound signature"? If there is a physical mechanism, why can’t it be measured?

How do you quantify "neutral", "bright", "dull"? Compared to what? Hint: you can’t. These are all subjective descriptions with meaning only to you. Others may have a different interpretation, thus, your claim is true for a population of 1- you.

We can measure the objective performance and studies have shown correlation with those measurements with subjective opinions of "quality".

More "you can’t measure it, but trust me"....Praise the lord...

Do I like the fact that the LSA shows more roll off at lower impedance loads?....no, I don’t.

Ricevs.....+100.....on your above post .....

Cheers.......

"However, there is a person who might chime in here who has a modded LSA and before that had my modded IceEdge amp which has no roll off using lower impedances."  😀  Chime

The thread were I did the review was noted earlier (and again it is here

However, there is a person who might chime in here who has a modded LSA and before that had my modded IceEdge amp which has no roll off using lower impedances).  For the guys who insist that measurement is everything, the first thing you should know that my hearing has been tested by an audiologist and I had an appointment with my ENT a couple of months back and I asked if he wanted me to repeat the hearing test I had the year before and he said no my hearing was wonderful.

My friend who was over also has excellent hearing.  Besides the listed playlist in the review, we listened to tons of things, some of which be indicative of deficiencies in upper frequencies (and the tonality was just better and more realistic, including the below as well as a couple that what whathifi lists as the 10 best tracks to test treble and notes "Coarse or rough treble doesn't always reveal itself straight away, and it might be a while before you realise what's missing when that upper register is overly rolled off, so it's worth taking some time to focus on precisely what's happening up there" and the 3.7 measurements are listed in a Stereophile review) Is the LSA the best sounding amp in the world - of course not - but the question should be what does the competition sell and how does it compare and I've owned a couple of Class A /A/B amps around the $9k range which were not as good to me or others who heard the actual system and of course those observations are limited to those specific amps -  and that is what the thread is supposed to be about - how the amp sounds in the real world with real speakers in a real system).  My advice to anyone is buy what you like and listen to it and don't worry about anything else.

More     "We can measure the objective performance and studies have shown correlation with those measurements with subjective opinions of "quality".

Again, I politely ask you......Show me the double blind studies that show a measurement of electronics can be shown to correlate with subjective sound.  You cannot....because they don't exist.  Your whole world is based on a belief structure that has no support.......it is like you are on a limb and sawing.....have a great flight!

We have not invented a measurement tool that can tell us why parts, wires, brands of solder, etc. to infinity and execution make different sound.  Of course, these are physical properties.  Our measurement tools are very crude compared with our ears ability to hear.   This is a fact....one that objectivists just cannot get their minds around.  They think our measurement gear is made by God and it is infallible.  Just keep sawing.....only gets more fun when you fall.

More "I won't listen, but trust me"......Praise the distortion measurement machine (their God).

God is Love.....not a machine.  The music that great machines can make (a great stereo) can move us to feel this God of Love....this God of Joy......I wish you all that feeling.

@kuribo there you are Chris. Thought maybe a Samurai got you with his Katana sword. Not the motorcycle.

@kuribo I will say you are not giving your Crusade up against Modifiers and LSA.

Studies are out there. Do your own homework.

You speak for a population of 1 with your subjective "impressions". They have no validity for anyone else.

We have not invented a measurement tool that can tell us why parts, wires, brands of solder, etc. to infinity and execution make different sound. 
 

Because it has never been established that they do.

More facts, substance, less religion.

@jaymark .  Hope you enjoy the X5's. They do need a break-iin. But  man i do love them.  I have some absorption panels in the back of them as suggested by Clat\yton. 

I bought a Topping PA5 that just got measured by ASR - almost as good as it gets measurement-wise..Will A/B test against the  LSA Voyager.

I call BS.....show us the studies....you cannot.

We all speak for a poplulation of 1.......this is what this game is.  Every man for himself.......praise be those that actually listen for themselves and make up their own mind.

When you listen to parts and execution and swap them......it will be established....in your mind......that they sound different.  YOU HAVE TO LISTEN.   If you are not willing to listen then you will never learn ANYTHING about sound.

I have told this TRUE story before.......but it is a good one that illustrates the problem.  There was this guy who believed that amps sounded different but that wires did not.  He had just met a person new to audio and had told him of his opinions.  These two were invited over to another audiophiles house that had modified Soundlab electrostats....along with another person (4 people total).  When they were there they wanted to do a comparison of two different interconnect cables.......once this started the "non believer" went into the kitchen and stayed until the shootout was over......he could hear their comments while in the kitchen.  All three of them (including the newby) all heard significant differences between these two interconnect cables.  Then he comes back in the room and says nothing.  If he had stayed in the room while they listened and they turn to him and say "well, did you hear what we all heard?"  what could he say?  If he says yes, then he would have been "WRONG" all those years.....not good for the ego.  If he said, he did not hear any differences....then the other 3 would think he cannot hear and he would never get invited to anything again.....also not good for the ego.  So, he got to keep his ego intact by putting his head in the sand.  So, the question is.......Is your head in the sand?  I would think its pretty dark and dim in there.  Not much fun.....although you can put down others who listen instead of hide.  

Not listening and thinking you know something about sound....well......its pretty stupid.  Why don't you keep your eyes closed and then you will know everything about how things look.....right? or wrong?  How about not touching things and thinking you know how things feel?  We could go on and on.  

If you want to worship measurements over sound qualtiy (as heard by the ear)....then fine.  But to think this is what most here do?  This is stupid.  The measurement worshipers are a few very vocal people trying to save us from all those that listen.

Now, we have said the same thing over and over again....haven't we?  Shall we keep dancing?  I think I will choose another partner.  Has been lovely........love yourself and everyone.  I love you.

The Topping PA5 was almost as good as the  Benchmark AHB2 measurement-wise.  He liked the sound also of the PA5. Ha!

Yo baby!  Top of the morning to ya!  What a great measuring amp (PA5)......I cannot wait for someone to send me one to mod.......he he.  It's amazing what the Chinese are doing with their cheap DACs, preamps and amps these days......simply amazing.

@timing3435 taking his measurements on his state of the art gear.

I have never said don’t listen as obviously that is what these devices are made for. What I have said is don’t give your money to charlatans who make claims without a shred of evidence, who like to tell everyone what sounds best, and who continue to preach and pontificate a religion while denigrating science. No one likes a parasite.

You want studies? Read Geddes, Hawsford, Otala, etc. You are the one making the claims, the burden is on you to provide evidence. But, you can't.

And I see you failed to answer my question- what is the physical mechanism that causes passive components to alter the input signal to such a degree that it is audible to the human ear?

Chris your Crusade is getting very boorish.

What I have said is don't give your money to charlatans who make claims without a shred of evidence, who like to tell everyone what sounds best, and who continue to preach and pontificate a religion while denigrating science. No one likes a parasite.

@ricevs ,

I don't mind aggression in a technical discussion, but you are just making up conclusions that stating things that show you don't know nearly as much as you think you know:

Again, I politely ask you......Show me the double blind studies that show a measurement of electronics can be shown to correlate with subjective sound.  You cannot....because they don't exist.  Your whole world is based on a belief structure that has no support.......it is like you are on a limb and sawing.....have a great flight!

Floyd Toole, Stanley Lipshitz, James Johnson and a whole host of other people you have not heard of have spent their whole lives researching, often using blind testing, the impacts of audio reproduction and how that impact how we perceive sound. It is how we know about things like in-room response preferences, the important of flat on axis response, how we are more or less sensitive to some types of distortion, about masking functions w.r.t. frequency response, about limits of human hearing, about masking of quiet sounds by loud sounds, about audibility of jitter in digital playback, about perceptual impressions of noise, etc.  And everything I have just listed in affected by the electronics.

Assuming that the OP experiences an audible difference with the LSA amp and it is not just bias, and I am very much inclined to believe that he is experiencing it, it won't be explained by solder, or silver versus copper wire, or binding posts, or AC outlets, or power cords, it will be explained by real and significant differences. Those differences won't be explained in platitudes from audio reviews either. They will be explained by cold, hard science. The measurements on ASR of the LSA amp, and taking into account the impedance of the Revel speakers, and what we know, from extensive scientific exploration of audio, is what will explain it.

We know from Toole's/Harman's extensive work on preference curves that people prefer something close to a in-room response that declines in output slowly from the mid-bass to the high frequencies. We know that excessive high frequencies make the sound harsh/bright, that they mask detail in the mid-range. We know that tubes amplifiers almost as a rule have lower damping factor that gets worse as frequencies go up, and that this will cause high frequencies to reduce in amplitude especially with a speaker like the Revel. Reducing the highs can remove an impression of harshness, especially in rooms that are highly reflecting, and that removes the masking function on the mid-range, allowing the mid-range to appear smoother. We know that Class-D amps have high damping especially in the bass, and that generally contributes to tighter bass compared to tube amps. Tube amps can have higher IMD which will impact mid-range / high frequency detail. The op stated that the LSA was like the best of all worlds, tube and Class-D/SS.

I previously stated the characteristics of the Revel. The LSA has some defining properties. It has reducing damping factor at high frequencies. With speakers like the Revel, this will result in a fairly significant (1.5-2db) and audible reduction in high frequencies. The LSA like other Class-D has great damping factor at bass frequencies which will contribute to tight strong bass. The reduction of the highs will both reduce perceive harshness, and will reduce the masking by high frequencies allowing the midrange come across clearer. In addition, the LSA has very low IMD, which will further improve clarity in the midrange. No magic unproven hypothesis about minor components, just significant and real differences, yes explained by frequency response, damping factor and distortion.

I will further add that frequency response will have by far the largest impact on imaging / soundstage, so an amplifiers interaction with a speaker, if it impacts frequency response is going to be by far the biggest contribution in the electronics chain to imaging/sound stage. Again, not solder, connectors, some wire in the amp, AC sockets, power cords, etc.

I'll chime in here with a long post (and I hate long posts).  At one point starting over 20 years back for about a 6 year period I had a friend who worked in a high end audio store and during that time, I did most of the set-ups and installs with him (to get them done quicker and we could either go back to the store while it was closed and do comparisons that most would not be able to do or head out for beer and appetizers).  I heard many things which I set-up in different rooms and with different electronics, including things which I owned.  I've heard things I've owned (both electronics and speakers) that sounded better and worse (I'd say more worse since I had the benefit of the experience in positioning and setting up things).  I heard a pair of speakers that I owned once that sounded so bad in the roof I couldn't stand to be in there.  I've also heard amplifiers I've owned set-up with other things that just didn't sound as good.  So the point is to evaluate something, there are different ways of using those things as the same components measure the same (and some of the 2-channel systems 20+ years back had over $150,000 of stuff in it at retail. And by the way, there were very expensive amplifiers that on occasion had something that was not soldered correctly.  A sample of one or two of anything is not very scientific to come to the conclusion it sucks (and one of the amplifiers were sold in monoblocks at $20k retail).

I do own a one third octave RTA (Audio Control) for many years,  I also have the Audio Tools App with the Dayton Audio IMM-6 mic and REW on PCs and a Dayton Audio UMM-6 mic.  My philosphy is to mitigate the bad room issues (via treatments and placement) and not have the room look like a recording studio since I have to live in it.  In a perfect world (and with more funds and anyone is free to contribute towards my goal😀) would be to have two more rooms, one optimized for 2-channel and one for HT.

Many moons back Mark Waldrep of AIX showed up at a Capital Audiofest I attended.  I bought a Blu-Ray with hi-rez audio content and since it was quiet when I went, I got almost a 20 minute spiel on DSD measurements and the audible noise.  I politely listened and since I like his recordings all I had to say was that as a consumer I have no control as to what a record label chooses to release in SACD or DVD-A and can only buy what's available.  I didn't have the heart to tell him that the Meitner MA-1 DAC I had at the time upsamples everything to 2 times DSD (no user adjustments are possible) and pushed all the measurements he was referring to outside of the range where my dog couldn't hear it.  The point being that an amplifier or any other thing in the listening chain needs to be considered, which brings me to the point of my system and how it is used and that everyone using the LSA may not get identical results (and some of course may find high frequencies better or worse in their systems in their rooms).

I'd also like to say that I've had several others over my house who would agree that how I'm using the equipment I have sounds best in my set-up.  I use a Lumin U1 music server which reads files from my NAS in another room.  The U1 is connectoed to my EMM Labs DAC 2X (Version 2) via a USB cable (and I'm not going to go into those details as this thread already has cases of cans of worms)  and has Leedh (you can Google it - the post is long enough without it) volume processing built into it.  The DAC 2X gets output into my Modwright LS 36.5DM preamp and that goes into the LSA amp.

The DAC 2X upsamples everything (no user controls) to 8 times DSD.  When the Leedh volume processing is used, it can't do DSD volume control in the digital domain so single rate or double rate DSD files show up on the Lumin App as 352.8kHz and then the DAC upsamples that to 8 times DSD.  So that's as simple as I can make it. 

If moved the LSA amp to mysecondary back-up audio system (which I don't intend to do), I'd be listening to a Sherbourn preamp, a small fanless PC running JRiver (also for fun I have an Oppo 103D, which also can read files from the NAS hooked into a modded Carver C-9 Sonic Hologram generator via analog in and outs going into the preamp) going into a Teac UD-503 DAC. I have Selah Audio SA-2s (stand mount 2 way with a Fountek ribbon tweeter) and a Rel Strata III sub for speakers (along with the EVS 1200 amp.  The room is a smallish bedroom (I do have it treated) and with different equipment and the room, I might hear different things in the high frequencies with the EVS 1200 amp vs. the LSA amp than I hear in the main system.  Both amps would measure the same before and after I swapped them between rooms.  That does not mean I would hear identical differences in high frequencies in each room or any thing else.

One of the songs I used in my amp comparisons is 'Fistful of Swoon' by Vandaveer.  I've seen them live over a half dozen times (at my favorite music venue which closed over 4 years ago - the Iota Club and Cafe in Arlington, VA) and heard them do the song (just acoustic guitar live) at least a few times.  I've owned 5 amps (3 class Ds and 2 Class A/ABs) during the time I've had the recording.  I can tell you that the spacing between Mark Charles Heidinger and Rose Guerin on the soundstage was the most realistic on the LSA (it was uncanny).  I've also heard the cut on many other systems both people I know where I've brought it over or at an audio show (although of course I'm not as familiar with those as my own system) and I've not heard it in the same way (of course at audio shows the really expensive systems are usually in larger rooms with more people and often they don't have the time to do requests the way a smaller room would with a dozen or so seats and I'd imagine it would be better on those megabuck systems).

I have heard of those researchers and read much of what they did.  Again....none of them proved by double blind testing that electronics (or passive parts or execution) sound different because of distortion measurements.   Electronics practically all measure flat in frequency response.  Even with frequency response:  Have you ever had a 20 band equalizer with a 20K setting and moved it down -2db?  Do you think you can hear that?  Most of us here do not hear above 14K.  Of course, if you did 1K we would hear that quite a bit.  I am sure that different kinds of measured distortion are audible....like more odd harmonics or whatever.  However, there has never been a double blind test that shows this.....or any other test on distorion measurements....please find one.  Until they do these tests.....it is all just the subjective opinion of the person doing the change that we here about.  Nelson Pass says he hears a difference.  I believe him.  However, he has no proof. 

By the way, Nelson Pass told me that he believes that "What I do works, but he has no interest in it."  He likes playing with ciruits and transistors.  He does not want to go down the rabbit hole of infinite tweaking.  This was a response from him....after I told him I could come to his factory and help him tweak his components.  This tweak game is time consuming.  He makes plenty of money making products the way he does and is very happy.  No problem.....we all have different desires.

Speakers are another story.....the frequency response, polar patterns, waterfall plots, impulse response, time alignment and distortion....all all quite gross and audible....and easily noticed on blind studies.  We are talking electronics here.  Please show me the study that shows how distortion numbers correlate to sound.  

Since this has gone into so many tangents...here's another one

Jaymark: how does the X5 midrange sound?

I'm into OB too, although DIY, and have the same Beyma AMT and wonder how those Deltalite 2512 mids sound and your experience with potential beaming from a 12" mid. Love the high sensitivity midranges. Never heard a 12" though (have 8").

Cheers!

@ricevs 

 Electronics practically all measure flat in frequency response.  Even with frequency response:  Have you ever had a 20 band equalizer with a 20K setting and moved it down -2db?  Do you think you can hear that?  Most of us here do not hear above 14K.  Of course, if you did 1K we would hear that quite a bit. 

Your statement above shows that you have spent 0 effort trying to understand how the LSA amp would behave with a real load, and especially with the ops speakers. Instead you insist on grasping onto things like solder or connectors, or ... and no they have not wasted time on a double blind test, because that is just what it would be, a waste. I think if you search long and hard, though you may find one on capacitors in a cross-over, but the result will not be to your liking.

I have explained, in excruciating detail, how electronics, in this specific case, will absolutely effect listening impressions. I have brought you to the water, but I cannot make you drink.

I believe Nelson Pass was just being polite. Anything he has put down to paper (i.e. on the record) has been backed up by actual data, i.e. he tackled the potential for frequency response variance with cables. He has never, to my knowledge, given credence to "tweaks", but he understands his customer base, so he knows not to put them down either. It would not be good for business.

In terms of how distortion contributes to perceptions of sound, this is just every day common knowledge now (or should be if you are claiming to be an amp expert) including what we perceive as pleasant, unpleasant, how it may impact loudness impression, masking functions, etc. As always Google.