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In Reply to: RE: N core posted by Davey on December 31, 2017 at 07:41:51
An amp shouldn't render all recordings to sound "boring" like a dead hand was placed on the dynamics. This is a common high feedback amp design coloration that doesn't appear on static measurements because it is something going wrong with dynamic relationships and or time/phase relationships.
Follow Ups:
Brad,,
That kind of sound Has nothing to do with feedback , feedback is just one part of a very complex audio amp loop of variable structure ..
PSU
Amp bias
Output stage topology
Gain
Feedback
Driver stage
Beta droop
Z" load
Bias drift (SOA )
Open loop bandwidth and stability
Et al ,
On and on ,
Feedback amount , local or global is but another in the "loop" .... :)
Regards
Ok, but I have heard this problem, primarily, with amps that had a high amount of negative feedback. Whatever their other flaws, I have rarely heard that issue from no feedback amps.
Putzy amplfiers or class D in general , at least the ones i have heard sound far from dead , as a matter of fact with an unheard use of large amounts of negative feedback dead is not how i would describe class-D sound. IMO, they have issues with timbre , instrument size ,finesse and lack a proper soundscape for the illusion of realism.
Dead they are not , good class-D have good jump , better than a lot of class a/ab amplifiers but they bring other issues that may or maynot be offensive to those using them .
The big advantage of Class-D IMO, is the access to high affordable power , this usually eliminates clipping , making music sound more dynamic to those living with clipping for years via under powered Amplfiers ..
Regards
I don't agree about ncore sound. It has an unnatural sheen to the sound...a lot less like delta/sigma digital. True, it is not as dead sounding as high feedback Class AB but when a 30 watt tube amp can out dynamic it on normal (90db) speakers then I would not consider it terribly dynamic. Power is not to be a good indicator for this "Flattening" of the dynamic envelope.
Brad,
"Boring" is a totally subjective term used in this context.
You say a "dead hand placed on dynamics," but that's a meaningless conclusion/comment.
In my way of thinking, "boring" probably means an amplifier that is very close to the "straight wire with gain" that many used to talk about. An amplifier that adds (or subtracts) nothing from the sound, but simply provides the necessary voltage gain and current requirement.
Dave.
I'm not so sure in this case. I've been puzzled by the same phenomenon in my AHB2. It's the cleanest amp I've ever heard, precisely as one would expect given its vanishingly low distortion and in particular its feedforward compensation for crossover distortion. But I have the impression that the transient reproduction doesn't isn't right. I have no idea why from a technical perspective -- I can think of many possibilities, given the design -- but the transients seem rounded off, and that sucks the life out of the music. I don't think we're talking the absence of distortion here.
If transient production isn't right, and transients are rounded off, that's distortion Josh. :) (Whether it's measureable or not is another task.)
Stirring the pot with these guys, I was purposely talking with diffuse and not concise language. :) It's always some subjective aspect of the performance they hang their hat on. I have no problem with that, but you can't have it both ways.
Dave.
You have a point. :-)
For what it's worth, and speaking personally rather than technically, I prefer "straight wire with gain" accuracy. I find that euphonic coloration becomes cloying and annoying after a while and I don't think that distortion adds something to recordings of acoustical instruments, which in real life have a gusto and purity that makes our efforts sound pathetic, and so no lack of impact!
Speaking technically, I'm really curious about this issue of dynamic distortion. Clearly we're missing something because this doesn't seem to show up on steady state measurements of the harmonic spectrum or IMD, which I find normally correlate pretty well with the way a good amplifier sounds in its linear range for reasons that anyone who has ever played with additive synthesis and noted the effect of harmonic spectrum on timbre will understand. And it doesn't seem to show up on conventional dynamic measurements, either, we've known how to deal with TIM for years. The main candidates I can think of are feedback loop issues, power supply impedance/sagging, and the way the amplifier/feedback loop responds to back EMF, which could explain some of the long time constant stuff I hear on piano ADSR. But the AHB2 is a complicated beast, what with its feedforward amp (if I understand correctly) and rail switching, so I can see other possibilities -- assuming I'm not imagining things!
I think most hear understand 1) what boring means and 2) understand when all recordings are exhibiting this trait then the signal transmission cannot be as pure as the measurements claim...unless you think accurate reproduction of recordings should sound boring. Doesn't show much faith in those making the recordings...
Well, I disagree on both points.
I think "boring" might have a different meaning to many listeners....and certainly depending upon the context.
AND when all recordings are exhibiting a particular trait, that's NOT boring....Something is wrong.
This is a perfect example of how the "language" of audio subjective evaluation has become so vague and meaningless.
If we're going to hang our hat on this type of language, we have to live with the pesky questions that come with it.
Example, and one you might appreciate: A guy returned one of my Apogee active crossovers many years ago and told me it didn't have any "jump." I told him on the phone it's not supposed to have "jump." Silence on the other end.
I sent that same crossover on to another fella with Diva's and he replied "it's very dynamic, I haven't heard my Diva's exhibit that amount of dynamics, ever."
It's very tricky to make conclusions based on insufficient information.
Dave.
I think I was the first person to use the word "boring" on this thread to describe one particular amp.
The amp in question is the Benchmark AHB-2. Yes it's boring to listen to, but yes, it's probably very accurate if its output is analysed on the test bench.
I described this amp's sound as such that one tends to want to turn down the volume and maybe to forward on to the next track. An exciting amp will have the reverse - the temptation is to turn up the volume.
Most valve amps have considerable distortion, but often sound better than SS amps with many speakers. They add excitement to the music and I don't care if it has poor results on the test bench - all I want from an amp is to enjoy my music with as near as possible as the enjoyment at a live venue. Would you not agree?
I certainly understand you premise that a power amplifier should add distortion, or whatever, to add excitement to the music. That's not a new premise. It's decades old.
I have a few friends who've listened to the Benchmark amp extensively (I had a limited exposure) and they don't describe it as "boring." I also have read the reviews on the amp in Stereophile, etc. None of these have mentioned a "boring" presentation either. So, it's my opinion that your boring subjective evaluation is flawed.
That said, no, I don't agree that an amplifier should attempt to create the enjoyment of a live venue. That's not its job. I'm not sure why that's such a difficult concept to grasp.
Dave.
> I have a few friends who've listened to the Benchmark amp extensively (I had a limited exposure) and they don't describe it as "boring." I also have read the reviews on the amp in Stereophile, etc. None of these have mentioned a "boring" presentation either.
Firstly, I think you should re-read my definintion of "boring" in my description of the Benchmark. I defined it as the urge to turn down the volume control (you don't want elevator music playing loudly) as opposed to exciting amps where the urge is to turn it up.
That said, please also re-read part of Stereophiles's review, in particular the paragraphs under "Listening in the Country". Expressions such as these crop up:
"the sound was somewhat hard and thin"
"robbed of some of its warmth and resonance"
"sounded strange. Both voices were higher, not in pitch but in tonal range, as if they'd been transformed from mezzo-sopranos"
"her voice was robbed of its bell-like richness by the AHB2"
These are an indication that this amp is very speaker dependent regarding performance, although (as I previously mentioned) their review is GENERALLY very favourable.
The Absolute Sound reviews says:
"I'm not sure I can in good conscience recommend this amplifier to them [audiophiles] as I am not sure they are in search of what it offers: a precision instrument designed to perform the precisely defined task of reproducing music and sound accurately"
HiFi Plus concludes:
"It seems fussier about speaker partnering than usual, however, and I would recommend trying it with your speakers before purchase"
Remember, when I bought my Benchmark there were no worthwhile reviews for me to read. I was influenced by an Avantgarde owner who thought it was the best amp in the world. After the very disappointing sound it offered through my AG speakers, I found a couple of reviews had been recently published. Of course I was looking for hints in these reviews that all was not as rosy as a quick read would suggest. Reviewers are never outright critical of the products they review, so I find that "reading between the lines" of a good review is most important in deciding whether a product should be bought.
Many people will be delighted with their Benchmarks as part of their system, but I found that most of the 8 or 10 other amps I've tried since were far better in my system than the Benchmark -
Hope this explains why I found the Benchmark "boring" and was pleased to get rid of it. I now have 5 alternative amps that are considerably preferable to listen to than the Benchmark. These by NAD, Accuphase, Gamut, Consonance (tube) and Micromega. Incidentally Red Wine and Quad together with the Benchmark were the most unsatisfactory.
of the whole Halcro 'lowest distortion amps ever' of maybe 15 years ago. Everybody loved them at the time, heard comments about their attack and possibly thinness (didn't pay a whole lot of attention because waaay beyond my price range) and, in just a few years, they were gone.
For the best amps ever, they sure disappeared quickly. Too much heroic effect to remove distortion, just like the Benchmark? I certainly don't know...
Ha-ha. Yes, but there is a place for very accurate amplifiers - and for that matter speakers. Recording studios need them. I have had both the Benchmark amp and ACT 50 Active speakers, both designed primarily for studio use, and was hugely disappointed by both. They are best left in recording studios where the engineers need them as an accurate tool in the work, rather than for audiophiles who want their music to offer excitement and enjoyment, even at the cost of a little inaccuracy.
Good clarification...not that anyone other than Davey seemed to need it. The only thing that puzzles me is why you are still trying SS amps with AG speakers? I have heard AGs owns SS Integrated with several models and the sound is always hard and too forward. The best AG demo I heard was with Audiopax electronic, a Lampizator GG DAC and Sound Galleries music server.
For many years I used tube amps with the Avantgardes. These were all power amps fed by the output from a Mark Levinson 390S - a CD player with variable (analogue) output and 2 digital inputs, one used for DAB tuner.
These amps included Art Audio PX-25, Art Audio Carissa (845 based), Graaf GM-20 (6C33C based), Audio Note 300B and Consonance Cyber 845 monos. Of these, my favourites were the AA ones and the Cyber 845. The Graaf (OTL design) was physically noisy (it buzzed constantly) and the AN was dreary.
A year or so ago I decided to look for a suitable SS design for a number of reasons - I'd spend more time listening to it, AG themselves build only SS amps, etc.
I certainly don't regret switching to SS and have no plans for returning to tubes, although I still have the Cyber 845s.
I've tried several amps with the best being NAD M12 with Gamut D200 and NAD M32 integrated.
I know where you are coming from with the tube vs SS , SET requires good design and the right speakers load to deliver , in other words "effort " where SS is much easier and plug and play for the most part with very little effort and little to no maintenance ..
Regards
> I know where you are coming from with the tube vs SS , SET requires good design and the right speakers load to deliver , in other words "effort " where SS is much easier and plug and play for the most part with very little effort and little to no maintenance ..
No, that's not really the situation, at least as far as my system is concerned.
My speakers are unfussy in as much as all amps can be used without horrors. When I bought the Avantgardes, many people said that horns and SETs were the made-in-heaven combination, so I acquired a good SET. My circumstances at the time allowed me to try other SETs for prolonged periods of time and I loved them all - except the buzzing Graaf and the dreary AN.
It was only after 10+ years that I thought that there surely must be a SS amp that sounded at least as good as the SETs. After all there are thousands to choose from compared with the "cottage industry" of SET builders - good as they are.
You will see from my other posts that my search for an equally exciting SS amp took quite a while and included some serious disappointments. However I feel I've achieved what I set out to do - find a SS amp that allows my horns to sing as beautifully as the SETs.
Peter
Mike over on the Shark runs his AG with toobs, i did hear them with the Toobs but he has also run them with SS and liked the extra grunt and control. With very low distortion amps the Pre-amp dictates sonics immensely, that's not to say it's not so otherwise, but very much so with very low distortion amplifiers.
Not unusual to see many SS amps being driven by tooby pre-amps ....
Regards
Edits: 01/04/18
So, you don't accept that an amplifier can have distortions that would result in a boring sound? I have heard just this effect with a number of amplifiers even including some rather expensive ones like the McIntosh MC501 monos. Your claim they are just being neutral doesn't hold water with real music experience, where live almost never sounds boring. Your premise that the other amps that sound more "alive" are sounding this way due to distortion makes little sense as distortion will invariably degrade a performance not enhance it. Also, your premise implies that nearly all recordings are somehow badly missing the core dynamics of the performance and we should just accept far from an alive sound because that is what was actually recorded. My own experience with recording live performances and possession of "direct to disk" recordings shows your implication to be wrong. Many recordings are far better than the gear allows you to hear them.
If there is a dullness or as we have been saying boring sound with all recordings then how can this be right compared to an amp that shows a wide contrast in dynamics and liveliness from recording to recording?? Maximum contrast between recordings is more likely to be correct rather than a uniform "neutral" sound...this is just another form of distortion. Of course you have to believe the original premise from th OP that the benchmark amp renders the sound boring...I know I got that feeling with the benchmark DAC.
One would have thought this an easy Process to understand , I guess not .... :)
Edits: 01/03/18
It is an easy process to understand. Do you need some help with the basic concept??I believe that a power amplifier should be (as close as possible to) a straight wire with gain. How difficult is that to grasp?
I assume you disagree. That's totally fine.
My goodness.
Dave.
Edits: 01/03/18
Well you seem to know so much you are even making up my responses .. :)
The "perfect" amplifier is a straight wire with gain, Big foot is considered pretty fast and gainly ,
which have you seen ... :???
Regards
Edits: 01/04/18
I'm not sure why you're still adding your two cents in this portion of the thread.
Brad is a fella that outlines his thinking rather well. I may agree or disagree with it, but it certainly warrants reading his posts carefully. In other words, I know where he's coming from.
You, OTOH seem incapable of anything but pedantic and juvenile replies.
If you don't mind, please don't respond to any further posts I make in this thread. Thanks much.
Dave.
Excuse me for trying to communicate at your level ... :)
I had lost you way back when you couldn't grasp how loudspeaker imp/ phase affects the sound of amplfiers, why Brad wastes his time with your circular nonsense is beyond me, being a research scientist , i guess he loves the chase ...
Regards
Well, I'm not sure what the juvenile insults are all about, but you've illustrated my point perfectly.
I really don't have a clue who you are, or if you have any expertise in the audio field since you don't have the courtesy to identify yourself or even sign your postings.
And (not unexpectedly) you don't accept offline communication.
I asked you nicely previously, but I'll try again with an expanded request and ask you to no longer respond to any of my posts, anywhere.
I hope you can heed that request.
Dave.
My premise was very simply and clear.
Your post is total speculation on various other "premises" that I didn't state.
Dave.
You stated distortion is improving apparent dynamics to make the sound less boring...now THAT is really some speculation with not a shred of proof.
No I didn't. Read my previous post again.
I said I understood the premise that some folks think a power amplifier should perform that function.
You need to actually read my posts more carefully and not read between the lines. I know that's difficult for you. You had issues with that on the old Apogee forum too.
I've stated one, and only one, premise in this series of posts. If you choose to read it, then you can agree or disagree with it, that's your prerogative.
Dave.
No one has to read between the lines with your claims of "straight wire with gain" and if it doesn't sound interesting then it must be that the other amps are adding "excitement" distortion. Hogwash.
You have your credo plastered all over this thread. You are ignoring completely the listening aspect of the whole thing for essentially a view of "if it measures great and sounds boring then there is something wrong with the listener who can't handle the truth".
How is it possible for you to understand someone who thinks a power amplifier should add excitement? I don't understand this even though I think reproduced music should often not sound boring (there are of course some boring recordings...often with way too much compression). Audible distortion, either tonally or temporally, is to be avoided. The key word there is audible. If an amp sounds boring with most of a persons record collection there is likely something wrong temporally that is caused by some aspect of that product's design. Why is that premise so hard for you to accept? Because you worship the static measurements? Read some research into the validity of those measurements by Cheever, Geddes and way back Crowhurst.
You seem to fail to realize that the listener is supreme not the oscilloscope and that low measured distortion does not guarantee good sound or "true" replication of the original signal. There have been several studies showing this can easily be the case. Geddes even found a slightly negative correlation between THD and listener preference. HOW you get rid of distortion matters just as much (or more) than the distortion itself. Your understanding of these things is very superficial.
I think it was Richard Heyser who said " "Perhaps more than any other discipline, audio engineering involves not only purely objective characterization but also subjective interpretations. It is the listening experience, that personal and most private sensation, which is the intended result of our labors in audio engineering. No technical measurement, however glorified with mathematics, can escape that fact."
The "straight wire with gain" is an abstract concept. I didn't make it up, but it is (or has been) an objective for some amplifier designers to try and achieve. Certainly there are intangibles, engineering hurdles, etc, etc, that crop up along the process in producing a final (real) product. Whether those intangibles (distortions) produce a more realistic (live, boring, whatever you want to call it) audible result is open for discussion. Nevertheless, the original objective remains.....at least for some designers.
If you think the "straight wire with gain", or my belief that it is the correct objective for power amplifier design is "hogwash", then so be it.
I'm not sure why that amplifier design premise should be so difficult for you to grasp.
It's not just mine.....it's been the design premise of numerous audio amplifier designers through the decades.
Dave.
I am at a loss as to why you think I don't grasp such a basic concept and it is widely known that you didn't come up with it. Whether it is a worthy goal or not in the abstract is not much in debate...all amps should strive for the max linearity...according to the listeners. This is not as subjective as you think as there have reasonable attempts to correlate listener preference with distortion. It turns out to not be what most meter readers expect. The reason being the typical strategy for lowering distortion seems to introduce other issues, the most obvious being reduction of low order harmonics at the expense of making many more, sonically damaging high order harmonics. In other words the PATH to lower distortion is arguably more important than magnitude of the reduction. The impact is highly non-linear.
Linearity according to the scope is not weighted for the impact of those residual distortions on the listeners. Cheever and Geddes both came up with exponential weighting with increasing harmonic order. Once accounted for there is a big change in ranking for sonic "straight wire".
"all amps should strive for the max linearity...according to the listeners."
That's an interesting statement. I hope you're not speaking for most listeners. :)
I believe many listeners don't give a hoot about linearity, or distortion performance, or any other objective evaluation characteristic of power amplifiers.
I think you are, at least somewhat, in that camp as well, yes?
Your treatise on why nearly all audio amplifiers are incorrectly designed establishes your baseline on this topic. Unless you've pulled back on your premise regarding this???
Dave.
They may not care on a technical level but many of them care about it sounding more realistic. Correlating what they find more realistic with measurements IS interesting or at least should be to every audio designer... not just a demonstration of design complexity chops.
I walk the walk, having only SET at home. Linearity within the SET domain though is of interest to me, which is why I go with amps from Aries Cerat. Ultra stable and quiet power supplies and using the most linear tubes and design techniques.
Yes, unfortunately walking the walk to Aries Cerat land is extremely expensive.
Very interesting power amplifier products nonetheless, but not an example of what the audio industry should be producing nowadays. IMHO.
Dave.
Your last sentence is rather odd. Why would AC gear not be what the audio industry should be producing? Because of what? Heat? Weight? Price? The "industry" should produce the best sounding gear possible, IMO. AC represents one company's vision of what it takes to do that.
Cost, of course.
Dave.
Just the last one .... ? :)
You should request a list of acceptable amplifier designs and forward it to AC... BTW you need to give the name of at least one giant killer Class D , best of the best ...
Regards
Edits: 01/05/18 01/05/18
Actually if you look at the Milliwat to 1 watt distortion on tooby amps distortion is very low , this is the RMS sweet spot when listening domestically on 90db/w/m speakers ..,
Regards
Davey,We are obviously discussing in absolute terms and i know you know this , so why the silly retorts.
All Situations are, but not limited to , impedance mismatch , power cables , IC, pre-amp drive, setup experience rah ,rah ,rah , has to be taken into account and dealt with before commenting, many obvious reasons why novice type mistakes can account for varying results as you experienced with your active xover sale ..
Your Thesis ,One thought it dead no jump , you , it's not suppose to have Jump. Another thought it dynamic, well , adding the ying and yang content its not suppose to sound dynamic, right ..?
:)
Edits: 01/02/18
I thought I was talking to Brad here. I guess not.
Dave.
Such an amp will not sound Boring , as it will render recordings without interference , dead low DR recordings will sound as such , lively high DR recordings will sound as such .
When all recordings have the same presentation is when this becomes an issue ..
Some years ago, An amp designer I'm friendly with had an amplfier like that , not boring , the opposite, lots of jump on all recordings , adding its own flavor, this added feature was obvious when we played our own studio recordings where one in particular had an added 50hz boom put in for massive kick drum effect , his amp squashed it , tighten the bass with so much grip the boom disappeared into the back ground and was not pronnouced at all, so what most were praising as controlled , accurate tight bass was not ..
This kind of coloration and to be more precise "distortion" is not obvious on the bench as the amp measured exemplary ...
Regards
So a straight wire with gain is NOT "boring." I got it. Whew!
But hold on now.......you said "Boring." What's the difference between "boring" and "Boring"??Seems like you've made a conclusion on your friends amp with little facts to support it. If the amp measured exemplary on the bench, then clearly the measurements were not sufficient and/or your subjective evaluation had some other explanation.
The immediate knee-jerking to a position that bench testing is inherently insufficient to identify subjective performance is just the easy way out and indicates a lack of intellectual curiosity. I submit that a more rigorous testing scheme probably would have identified the "issue" you noted. Or at least given you some further insight.Dave.
Edits: 01/02/18
Seems you misunderstood what i wrote , please read again , i gave enuff factors to support my position , so much so the issue was addressed by the designer ..
Regards
Edits: 01/02/18
A romper room Prose ,,,,, how the mighty has fallen ,...
Regards
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