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Home Theater Shack 2015 High-End Amplifier Evaluation Event Reporting and Discussion Thread

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#1 ·
Home Theater Shack 2015 High-End Amplifier Evaluation Event Reporting and Discussion Thread



:fireworks2:
:fireworks1:




This thread is a continuation of the High-End Amplifier Evaluation Event Preparations Thread previously under way.



The event has begun. Coming to you from southern Alabama, the Home Theater Shack Evaluation Team has assembled at Sonnie Parker's Cedar Creek Cinema for the 2015 High-End Amplifier Evaluation Event. We have amps, we have speakers, we have tunes, we have great eats, what more could one ask for?

Be reminded of the first law of audio evaluation event execution. They never go exactly as planned. Not everything gets there, not everything works, but you endeavor to persevere and get things done.

We have deal with speakers not able to reach us in time, with cabling issues, with equipment not interfacing properly, a laptop crash, with hums and buzzes and clicks and pops, with procedural questions - - - yet we forge ahead, adapt, evolve, redirect, and forge ahead some more - - - and the task of evaluating amplifiers is underway.

Speakers: We were unable to get the Chane A5rx-c and the Acoustic Zen Crescendo Mk II speaker pairs. We are running the Spatial Hologram M1 Turbo v2 and the Martin Logan ESL. Both are very revealing speakers, baring a lot of inner detail in our recordings. They will serve us well. The A5rx-c will be reviewed for HTS when available.

At the moment, the Holograms are serving as our primary evaluation tool. I will post setup details and interesting discoveries a little later. They are giving us a monstrous soundstage, the kind that eats small animals for breakfast, with extremely sharp imaging and very good depth acuity. They are extremely clear, getting into the realm of rivaling electrostatic transparency. Their in-room response is very good, with some expected peaks and dips, but still very listenable. The high frequency response is extended and smooth. The bass gives you that "Are you sure the subs are not on?" feeling on deeper tracks.

We decided to start with sighted comparisons and open discussion today, and blind tests tomorrow. The Audyssey XT32 / Dirac Live comparison has not been completed yet.

Have we heard differences? Yes, some explainable and some not. One amp pairing yielded differences that several evaluators are convinced they could pick in a blind AB test.

One thing I have learned for sure: The perfect complement to good southern barbeque is a proper peach cobbler. Add great company and you have a perfect get-together.

The Event
  • Date: Thursday evening, March 12th through Saturday evening, March 14th.
  • Place: Cedar Creek Cinema, Alabama, hosted by Sonnie, Angie, and Gracie Parker.
  • Evaluation Panel: Joe Alexander (ALMFamily), Leonard Caillouet (lcaillo), Dennis Young (Tesseract), Sonnie Parker (Sonnie), Wayne Myers (AudiocRaver).

The Amplifiers
  • Behringer EP2500
  • Denon X5200 AVR
  • Emotiva XPA-2
  • Exposure 2010S
  • Krell Duo 175
  • Mark Levinson 532H
  • Parasound HALO A31
  • Pass Labs X250.5
  • Sunfire TGA-7401
  • Van Alstine Fet Valve 400R
  • Wyred 4 Sound ST-500 MK II
The Speakers
  • Spatial Hologram M1 Turbo v2, courtesy Clayton Shaw, Spatial Audio
  • Martin Logan ESL
Other key equipment special for the event:
  • Van Alstine ABX Switch Box, recently updated version (February 2015)
  • miniDSP nanoAVR DL, courtesy Tony Rouget, miniDSP
  • OPPO BDP-105

As mentioned, our deepest appreciation goes to Sonnie, Angie, and Gracie Parker, our hosts, for welcoming us into their home. Look up Southern Hospitality in your dictionary, and they are (or should be) listed as prime role models thereof.

This first posting will be updated with more info and results, so check back from time to time.




Amplifier Observations
These are the observations from our notes regarding what we heard that were supported by being consistent between sighted and blind testing and across reviewers. While we failed to identify the amps in ABX testing, the raw observations from the blind comparisons did correlate in some cases to the sighted observations and with the observations of other reviewers. Take these reports for what they are, very subjective assessments and impressions which may or may not be accurate.


Denon X5200 AVR

Compared to other amps, several observations were consistent. The Denon had somewhat higher sibilance, was a bit brighter, and while it had plenty of bass it was noted several times to lack definition found in other amps. At high levels, it did seem to strain a bit more than the other amps, which is expected for an AVR compared to some of the much larger amps. Several times it was noted by multiple reviewers that it had very good detail and presence, as well as revealing ambiance in the recordings.

We actually listened to the Denon more than any other amp, as it was in four of the blind comparisons. It was not reliably identified in general, so one could argue that it held its own quite well, compared to even the most expensive amps. The observations from the blind comparisons that had some common elements either between blind and sighted comparisons or between observers are below. The extra presence and slight lack of bass definition seem to be consistent observations of the Denon AVR, but everyone agreed that the differences were not a definitive advantage to any one amp that would lead us to not want to own or listen to another, so I think we can conclude that the Denon held its own and was a worthy amp to consider.

Compared to Behringer
- bass on Denon had more impact than Behr, vocals sounded muted on Behr
- vocals sounded muted on ML compared to Denon
- Denon: crisp highs preferred compared to Behringer which is silky.
- Denon is more present, forward in mids and highs than Behringer.

Compared to Mark Levinson
- Denon seemed to lack low end punch compared to ML.
- Denon is smooth, a certain PUSH in the bass notes, cellos & violins sounded distant, hi-hat stood out, distant vocal echo stood out, compared to ML.
- Denon bass seemed muddy compared to ML which is tighter.
- ML more distant strings than Denon.
- Denon is slightly mushy and fat in bass. String bass more defined on ML.
- ML seems recessed compared to Denon.

Compared to Pass
- vocals sounded muffled on Pass compared to Denon
- crisp bass on Denon compared to Pass
- Denon & Pass both even, accurate, transparent, natural, no difference, like both
- Pass seems soft on vocals but very close.
- Denon has a bit more punch on bottom, maybe not as much very deep bass, more mid bass.

Compared to Van Alstine
- bass on Chant track was crisp for VA while Denon was slightly sloppy
- sibilance not as pronounced on VA as it was on Denon
- VA super clarity & precision, detailed, space around strings, around everything compared to Denon which is not as clear, liked VA better.
- sibilanceon Denon, VA has less “air” but more listenable, both very good
- Very deep bass more defined on VA, overall more bass on Denon.


Wyred 4 Sound ST-500 MK II

In the sighted listening we compared the ST-500 MK II to the Van Alstine Fet Valve 400R. The assessments varied but were generally closer to no difference. The Van Alstine got comments of being fatter on the bottom. The Wyred 4 Sound was noted to have slightly better bass definition but apparently less impact there, and slightly less detail in the extreme highs. Most comments about the midrange were not much, if any difference. An interesting observation here was by Wayne, noting that he did not think he would be able to tell the difference in a blind comparison. Considering the ST-500 MK II is an ICE design and the Fet Valve 400R is a hybrid, we expected this to be one of the comparisons that would yield differences if any. As I am always concerned about expectation bias, this was one that I was particularly concerned with. Van Alstine is a personal favorite for a couple of us so I expected a clear preference for it to be present in the sighted comparison. I felt that the Wyred 4 Sound amp help its own with the much more expensive and likely to be favored VA.

In the blind comparisons, we compared the ST-500 MK II to the Emotiva XPA-2 and the Sunfire TGA-7401 in two separate sessions. Of course, in these sessions we had no idea what we were listening to until after all the listening was done. In the comparison to the Emotiva, some notes revealed not much difference and that these were two of the best sounding amps yet. The ST-500 MK II was noted to have the best midrange yet, along with the Emotiva. It was described as having less sibilance than both the Emotiva and Sunfire. Both the Emotiva and the ST-500 MK II were described as unstrained in terms of dynamics. In comparison to the Emotiva it was noted to have solid highs, lively dynamics, rich string tones, and punch in the bass. The overall preference in comparison to the Emo was either no difference to preferring the W4S.

In comparison to the Sunfire, comments ranged from preference for the W4S to not much difference to preference for the Sunfire. The Sunfire was described as having more presence in the midrange, while the Wyred was noted to be shrill, lifeless, and hollow by comparison.

These comments varied a lot, but the points of convergence were generally around the similarities to three amps that would be expected to be most likely to be different, if we found any differences at all. The objective results is that we failed to identify the amp in ABX comparisons to two other much more expensive amplifiers. I would have to conclude that based on the results, the ST-500 MK II represents one of the best values and certainly should satisfy most listeners.​





Audyssey XT32 vs. Dirac Live Listening Comparison

Last year HTS published a review of a the miniDSP DDRC-22D, a two-channel Dirac Live Digital Room Correction (DRC) product. The review included a comparison to Audyssey XT. A number of readers requested a comparison of Dirac Live with Audyssey XT32. That comparison was recently completed during the Home Theater Shack High-End Amplifier Evaluation Event at Sonnie Parker's Cedar Creek Cinema in rural Alabama. This report provides the results of that comparison.

Go to the Audyssey XT32 vs. Dirac Live Listening Comparison Report and Discussion Thread.


Spatial Hologram M1 Turbo Speakers

I was very pleased with the Spatial Hologram M1 speakers we used for the amplifier evaluation, and felt that they more than fulfilled our needs. They did not become "gotta have them" items for any of the evaluators, although I had thoughts in that direction once or twice. But they were speakers we could easily ignore through the weekend. I mean this as a high complement. Never did an evaluator complain that the M1 speakers were "in the way" or "holding us back," and we were able to focus on the task at hand unhindered. That alone means a lot, and may say more about them than the rest of the review just completed.

Here is what they did for us:
  • Because of their high efficiency, amplifiers were not straining to deliver the volumes we called for. We could be confident that the amps were operating in their linear ranges and that if we heard a difference it was not due to an amp being overdriven.
  • The stretched-out soundstage opened up a lot of useful detail for us to consider in our evaluations. In discussing the soundstage at one point, there was a consensus that it might be stretched a little too far and might be "coming apart at the seams," showing some gaps, although this did not hinder our progress. My final assessment is that this was not the case, all due respect to the fine ears of the other evaluators. I elaborate on this point in the M1 Review.
  • They served well as a full-range all-passive speaker, able to reach deep and deliver 40 Hz frequencies with lots of clean "oomph," all without the need for DSP boosting and without subwoofer support.
I thoroughly enjoyed spending time with them, and wish to again thank Clayton Shaw of Spatial Audio for loaning them to us. A complete review of the M1 speakers has been posted.

Go to the Spatial Hologram M1 Turbo Version 2 Speaker Review.


A Soundstage Enhancement Experience

Sonnie's MartinLogan ESL hybrid electrostatics were set up very nicely when we arrived, so we avoided moving them through the weekend. There were some improvements made to the soundstage and imaging by way of treatments, and some interesting twists and turns along the way which turned out to be very informative.

I have documented the exercise in a separate post.

Go to the Soundstage Enhancement Experience thread.
 
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#2 ·
Thanks, Wayne, for starting the thread so nicely and for all of your work, both technically and writing.

Another amazing weekend with an awesome group!

This set of reviews is sure to generate lots of questions and debate. Like the first speaker event, everyone needs to understand that we are not attempting to provide the answers to the perpetual great debates nor tell anyone what they should own. We are taking a journey down a path that interests us and asking questions that are meaningful to US in the context of how we enjoy music. Each of us has our preferences, beliefs, biases, and likes. We try to be open about what those are and, while we go to great lengths to set those aside and learn something, we don't apologize for who we and what we believe and like. We have no intention of competing with anyone nor offending anyone and have no agenda but to learn and play.

I try to make it clear where I start in terms of assumptions, expectations, beliefs, and experience. I am at heart an experimenter and look for explanations for everything. I also like to set aside all of the technical stuff and my attempt to understand the why and just experience the joy of people creating and performing great music. So you get two very different pictures if I am successful at communicating my experiences in these sessions. First, the more objective attempt to understand the performance of the equipment. Second, you will hear me speak completely subjectively about what I feel when listening. For me both are essential but I know that the former will never satisfy me, while the latter does. Ironically, I believe that the latter also yields some of my best assessments of the equipment. That will make the objectivists crazy, but as I said above, I don't do for anyone's approval.

I come to this weekend believing that we will likely be able to hear differences between amps, but far fewer than most audiophiles would report. I think we will find more differences in open comparisons than we can validate with blind testing. I believe that blind testing makes it very difficult to confirm differences but at the same time the characteristics of amplifiers that are reported by many reviewers are far exaggerated and unrealistic. I come with assumptions that some of the amps are better sounding by a slight margin but I don't expect that I know which ones they are. I came expecting more out of the Pass and Krell than others, but just based on prior listening to other products from those companies and my appreciation for the designers.

We will see what happens...the first day of listening has been interesting, with some differences noted in sighted listening and no differences in some comparisons. We'll see tomorrow how those observations hold up to blind tests.
 
#7 ·
:rofl: :rofl: :rofl:

Gotta love that!
 
#13 ·
The Cedar Creek Cinema is delivering the best sound I've ever heard in a home, Angie and Sonnie are the best hosts one can imagine, my listening companions are the best group of enthusiasts one could assemble for a weekend of A/V fun, Preston's ribeye was the best steak I've ever had, and Sonnie was thrashing my little Exposure into his EM-ESLs for a long time, longer than he spent with any other amp, thus far. Of course, that means he likes it best and the evaluation is now, for all intents and purposes, over and we are just going through the motions. Right? Right!

I am in the subjective camp, feeling that I can perceive small differences between most amplifiers, but also feel that these differences are largely overblown, in general. Today has confirmed that feeling, for me. Save one instance, I have not found any large differences that, blinded, I would be willing to put money against were I a betting man.
 
#14 ·
The Cedar Creek Cinema is delivering the best sound I've ever heard in a home, Angie and Sonnie are the best hosts one can imagine, my listening companions are the best group of enthusiasts one could assemble for a weekend of A/V fun, Preston's ribeye was the best steak I've ever had, and Sonnie was thrashing my little Exposure into his EM-ESLs for a long time, longer than he spent with any other amp, thus far. Of course, that means he likes it best and the evaluation is now, for all intents and purposes, over and we are just going through the motions. Right? Right!

I am in the subjective camp, feeling that I can perceive small differences between most amplifiers, but also feel that these differences are largely overblown, in general. Today has confirmed that feeling, for me. Save one instance, I have not found any large differences that I would be willing to put money against were I a betting man. That is the best way I can describe my take on an endeavor such as this.
Ok... then take the earplugs out and try again :rofl:
 
#15 ·
We spent Friday getting acquainted with the amps, listening to different amp pairs seeing if we could perceive differences. Most of us believed we could hear some subtle differences in some cases. In two cases, measurements showed there were differences that could be audible.

Last night we had some fun time comparing the ESLs with the Holograms. I am surprised how much alike they sound. Both have that easy, effortless clarity about their delivery that I have grown attached to. We have driven them pretty hard, and neither has shown signs of getting tired or holding back. Both are delivering monstrous soundstage with incredibly sharp imaging.

The Holograms have been our primary detail microscope for amp evaluation. Their wide soundstagre helps separate individual sounds and lets us hear the finer points of detail.

For the most part, the differences we have perceived have been impressions, not extremely specific. Today we will have a chance to try to confirm them.

A couple of us have noted that we heard no differences in the last 2 or 3 pairings yesterday, and wonder if that was a result of fatigue. So we may reverse the order of some pairings so we are hearing those last amps from yesterday with fresher ears today.

Today we will do blind testing for differences we thought we could hear yesterday.

Lots to do, must get busy.
 
#16 ·
I have conceded that my ears are inferior to these other guys. I literally cannot hear any differences between any of these amps thus far, even in some cases knowing there was a 2-3dB difference in a couple of the areas of the frequency response. At times I think I can hear a ever so subtle difference, but then I can't seem to repeat it with any consistency.

Being the above situation... it hardly serves any purpose for me to be a listener in the ABX blind testing round. Therefore I will be the setup guy for the blind testing. I have setup the following two amps as Amp A and Amp B:

DO NOT OPEN... DO NOT CLICK THIS BUTTON! >>>>>
Seriously? You really thought I was going to tell you what two amps they are? NOT!!!
Each of the four blind panelists will listen to X. X may be A or B ... and can be different for each panelist. After each panelist listens to X, I then switch the ABX box to Amp A. The panelist then gets to listen to Amp A and Amp B ... and can switch freely between the two amps. Each panelist will attempt to determine two things: 1. Which Amp was X ... and 2. Did they notice any differences between Amp A and Amp B. At the end of all testing... amps will be revealed and notes compared. In some cases I will pair the same two amps as yesterday so they can compare their notes from yesterday (knowing which amp was Amp A and Amp B) to their notes today (not knowing which amp was Amp A or Amp B).

Let the fun begin!
 
#20 ·
I've always felt there was more to be obtained with upgrading the speaker as opposed to the amp. If you have enough power to deliver the headroom, a good speaker will deliver. And treating the room is also paramount. Isn't it nice how good Sonnie's room preforms? Makes these evals better.
 
#24 ·
Whew! What a weekend!

Status: We got through our ABX test. Results are being compiled. And analyzed. And interpreted. And the mainframe is still cranking on the answer. Apparently there is some number crunching involved.

At one point the mainframe stopped as though it had an answer for us, but it turned out that it needed clarification on the question. Something about the answer being quite simple, something related to the number 42, but the question really needed to be defined properly, and that would take awhile. And maybe a bigger computer.

Leonard is in charge of all of that, and it might be a day or two, or three, possibly four, or maybe something more than five.... OK it will be A BIT before the results are published.

As of this moment... Joe and Leonard on on their ways home to Wisconsin and Florida, respectively. Travel safe, fellas. Sonnie is napping, Dennis is relaxing/posting/computing/napping. The weekend is not over, though, there is work that will continue through Monday.

A few thoughts on blind testing, and the weekend so far:
  • There are a lot of ways to attack blind testing, and it is not a simple creature to master.
  • Like anything else, it can be fun in the right company. Check the egos at the door, approach it in a supportive, friendly atmosphere, and a group can have a fun time while getting a lot accomplished.
  • These guys - Sonnie, Leonard, Joe, Dennis - are an unbelievably great bunch of people to work with and play with.
  • Expensive electronic toys are cool!
  • Expensive audio toys are REALLY cool!
  • Expensive audio toys can be frustrating!!!!!!
  • There are a lot of ways to look at value.
  • Good sound and good music and good company and a fun, tough, technical audio project all mixed together for a weekend make for a high that is pretty hard to beat.
  • Imagination is a wonderful thing, you know, the furnace of creativity and all, and it can be your friend, but it can lead you off in weird directions if left unchecked. It all depends on what you are trying to accomplish.
  • Sleep is good.
There is some detailed speaker evaluation work to be completed. And some other testing. It is funny how our TODO list never gets all checked off and finished, It just gets continually rewritten.

Will be posting some photos shortly...
 
#26 ·
Good question. I know in my family and my friends I am the only nut who "really" cares about the quality of the sound. My wife thinks the TV speakers sound great and my friends think a $2-300 soundbar sounds amazing.
 
#28 ·
I'm afraid we are bkeeler. My experience is the same. Mostly family, and most of them have been around long enough to have expectations. New guys(family or friends) are the ones I like. I'm not about to pound on my chest,as my system is modest, but no one as a first time visitor has not said WOW. (Just nice maybe?). Again, like bkeeler said, not many want to take on the variety of investments. It's for me anyway, but I still enjoy sharing it.
 
#31 ·
Well, I don't think this forum was ever meant to be appealing to the mainstream. Whether doing room analysis or building theaters or playing with two channel, most of us are interested in things that the majority is likely not. The group we assembled this weekend is surely on a different road than the majority of consumers as well as the majority of audiophiles. We share an unending curiosity and a unique willingness to challenge our own assumptions.

So what did we do and what did we accomplish? We listened to 11 amplifiers in paired comparisons under both sighted and blind conditions, using ABX comparisons in the blind assessments. We collected our observations both about the comparisons and the process, as well as collecting sweep data with REW.

Before we start getting into the results, let me be clear that we are not interested in pleasing anyone, and suspect that both sides of the "do amps sound different" debate will be largely unsatisfied with the results. These debates can get heated, and those who have been with us any time at all understand that we will not tolerate condescension, sarcasm, know-it-alls, nor any of the typical vitriol that is found elsewhere. We can have debates and even disagree strongly while being respectful of the right of others to have an opinion or perspective that differs from our own. We don't hesitate to "ask" those who don't get it to move on to another venue.

As Wayne said, we still have some work to do in terms of how we frame the results and the question(s) that we addressed. Not because we are trying to massage the results, but because it is very difficult to compile and make sense of all of the observations and to decide whether they are consistent across listening tests and/or individuals.

I previously stated my biases, assumptions, and beliefs. I don't like to speak for others but I don't think there is much doubt that we are on the same page. We went in assuming that we would perceive some differences, but that it would be very hard to support them in blind testing. Knowing this, we proceeded with ABX testing anyway, as we would like to come to some conclusions about the reliability of what we think we hear. We know that it is dependent on many factors and many of them have nothing to do with actual performance differences. Still, with so many different designs and price ranges, it seems inevitable that there may be some differences.

So what were the outcomes? I'll briefly satisfy the naysayers by saying that we completely failed to identify amps consistently in ABX comparisons (except for Dennis, who was correct in 5 of 7 tests). Overall, however, we were correct only 39% of the time, worse than chance. That said, there was evidence of something else going on. Dennnis and Joe both identified a couple of the amps in the blind testing from their experience with them the day before. They made notes to that effect during the blind testing. All four of us reported difficulty assigning what we heard as differences to the X amp, even though a number of our listening observations were consistent between the sighted and blind comparisons. It is quite easy to forget which was X in these comparisons. The testing process needs some work, and we have some ideas about how to proceed in the future to come up with more useful results.

We also did sweeps on the response from the speakers and with few exceptions, everything was similar enough to not expect frequency response to be audible.

We will be publishing the details of the tests and results, including the subjective assessments that were consistent across testing modes and listeners. It will take some time to go through all of the notes from 4 listeners for 7 blind comparisons and 6 sighted comparisons.

In the meantime, let the civil discourse begin.
 
#33 ·
Very interesting preliminary report in that a panel member was successful in identifying amplifiers in 5 out of 7 tests.
IMO that is a completely unexpected result, looking forward to the details.
Thanks in advance to all that have donated their time, money, and expertise into this project.
 
#34 ·
Thats not what he said. Dennis was the only one who called out correctly 5 of 7 amps. The rest of the group was a hit/miss of 40% correct.

Knowing this that leaves a portion of that 40% off to a "good guess"...

based on these results...

1. The backbone of the system might need to be supportive more to help distinguish differences (power, isolation, conditioning, cords, etc) which could attribute to help reveal these differences (I know this is flame territory speaking of this
2. Considering the 40% correct the realistic results is around 25% of people can hear differences
3. I want Dennis' ears :)
 
#38 ·
I will say that for me the difference between sighted AB comparison and the blind ABX test was big. With a number of pairings during sighted comparison, I believed I could hear subtle differences between the amps, even had a couple of "I like that amp" moments, but the ability to carry that level of discrimination over to a the blind ABX test the way we ran it eluded me and I did not do well there. Leonard can fill in the details when he has them ready.


We did quite a bit of work yesterday with the Spatial Holograms. It is funny how a single track can reveal things that no other track seemed able to. The mandolin and guitar on The House Of Tom Bombadil, by Nickel Creek, were giving me fits yesterday due to the widening dipole dispersion pattern and lower-frequency reflections off the front wall under the movie screen. We think we figured it out, though, and properly placed absorptive panels came to the rescue. We will do a little more experimenting there and finish the Hologram review. Then we will put a few finishing touches on Sonnie's ESL setup and call it a day.

Sonnie, Dennis, and I watched Abe Lincoln, Vampire Killer last night. Fun film, and a fun room to watch it in. You have probably seen pics of the stucco job he did on his walls. It is beautiful.
 
#40 ·
Keep in mind that we really needed more time to repeat the testing and see that identifying an amp can be repeated consistently among the same two amps over and over. This is one testing method we did not have time for. Not trying to discredit the ears of Dennis, but there was a chance that any one of these guys could have gone 7 of 7... or 0 of 7. We were more or less just having fun with this round and learning more about ABX testing.

We could have had more expensive speakers... more expensive cables... and a power plant in the back yard to help improve in the possibility of hearing differences... but we didn't. We can speculate all day long, but we had what we had and we did what we did... and as Leonard noted, not to please anyone here, but to have fun. We are sharing our results because we can and because we know there are some interested in seeing the results, but we could really care less for those who want to poke holes in it for whatever reasons.

What I ultimately took away from this was that if I feel I need an amp to power my speakers outside of a receiver, which I do because I have clipped my AVR amp on my speakers, then I need to find the least expensive amp I can find with the minimum power I need... and call it a day. I personally see absolutely zero reason to spend a lot of money on an amp. That is no way implies the same will be true for you... I simply proved for myself what options are best for my ears. :T
 
#43 ·
Well one of the main reasons why I was curious of this testing was this very fact... While I am leaning more toward the fact that amps make little audible difference when properly levele matched I do feel after reading and NOW agree that the biggest differences in amps that are audible are when they are driven loud are are driving into distortion.

I've read that and based on the results of these tests and some other publications I really do feel like amps make a minimal amount of differences IF driven into non distorted levels. This is solid state vs. solid state of course.. I do think tube amps sound different.

One of the only reasons I have a separate is the fact I got it for a decent price and that was that. After checking the actual test data my Krell can drive all channels into 108 watts at 8 ohms at .1% distortion and 136w at 1%... this is the actual test data of driving ALL channels at the same time.

Even checking current AVRs it takes a 2,000+ dollar AVR (typically) to be able to produce the same specs. My X4000 driving 5-6 channels only produces some 68 watts at 1% which basically means I can play louder and cleaner. than my AVR alone. I spent 2450 total on my AVR and amp which yes that could of bought me a high end AVR....

only issue is a high end AVR would be 1/4 the price in three years where my Krell value will hold true since it's market keeps the pricing current.

Now... something like the Outlaw 5 channel amp would be on my radar to test.... considering it's rated 200w each channel at .1% which gives me some 90w more headroom. Would love to hear that when playing loud and seeing if there are any audible differences.
 
#41 ·
Seems there is a decent amount of evidence to support the theory that differences between amps can be heard. The evidence also suggests that there are select few who can detect the differences by ear, and under very specific conditions. Which means... the debate will continue!

Seriously though, many thanks to this crew for putting so much thought and effort into the process. It has been very entertaining and informative so far. I'm looking forward to seeing the detailed results.

Edit: I will add that I pretty much agree with Sonnie. Although I think I have been able to sense subtle differences between amps, I have no proof that I could do it consistently. Spend what you need to get enough power to avoid clipping and you should be good to go.
 
#44 ·
Spend what you need to get enough power to avoid clipping and you should be good to go.
THIS!!!

I think this pretty much sums it up. Sonnie said himself he has clipped the amp. Me... I've ran these SVS ultras to 105db playing pink floyd with the X4000 in direct mode and the volume set to +8db and never heard of any strain at all.

Do I hear my room... ya it sounds like . But the speakers played loud and strong. Very happy.

Now... I will never play that loud again... the was LOUD wow. Toooooo loud. If I can play 90db with bass peaks around 98-100 then thats still plenty loud that I will ever need to go.

So for me, the price... me having seperates gives me plenty of headroom which should be everyones goal. More headroom = less distortion. and distortion is audible.
 
#46 ·
Not arguing that one or the views is absolute and carved in stone. But I thought the following quote from Lonnie Vaughn, Chief Technical Officer at EMOTIVA, offers a decidedly non snake-oil explanation for why amps sound different:

"Amplifiers do sound different for a number of reasons. Paul cites a good one, the square wave response. On a personal note, I believe the power supply plays a big part in the way an amp sounds. I get that the power supply accounts for the biggest part of an amplifiers cost. But so many companies take it down to the bare minimum required to meet the specs that there is no headroom in the system at all and the amp itself just sounds flat as a board. In these cases, all the designer had to do was put in a few dollars more in storage and it would have made it a completely different unit." (Taken from an article on this webpage)
 
#48 ·
Which is why all the higher end amps that have higher end costs have the big toroidal style transformers. My krell has a 1600w toroidal supply. cheaper units use standard transformer winding types. Or at least it's one of the differences I notice. does that make an audible difference... well who knows. The Denon tested has a normal non toriodal type transformer and that ended up falling last by the posts that was made?.... is that still true?
 
#47 ·
It's very interesting reading results/impressions of this testing and as others have said thanks for doing it. I've often wondered if adding a dedicated amp to my setup would provide any audible improvement. To be honest with my speakers I highly doubt it but with harder to drive speakers I think it would. If I were to add an amp it certainly wouldn't be a boutique name brand but something along the lines of Emotiva's price range. Oh those pretty blue lights are oh so tempting! :)
 
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