Stereophile | January 2017 Issue
- Thread starter NorthStar
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i thought seriously about Lamm ML2s when i finally went with the Grand Slamms...but i wanted long term optionality on power if i were to move to speakers that required a lot more power (Arrakis). otherwise, could certainly have been happy i bet with Lamm.
+1. Has been my hiccup with buying a KR amp - if they go out of business, you have a doorstop.
Not sure about X1, but Steve's X2s benefited quite a bit from ML3 as compared with ML2.
Just a small detail. IMHO Keith Howard did not absolutely debunk anything in his interesting work. I am not prepared to accept that his software generated distortions are representative of the analog distortions existing in real audio amplifiers. IMHO we must currently fight such "euphonic distortion" arguments in the subjective field not on base of this study - and I do not believe that SET "magic" is due to the usually called high level "euphonic distortions".
BTW Jean Hiraga findings on distortion spectra are most of the time misrepresented is forum debates - interested people should read the originals.
And yes, I consider that the process of making great high-end equipment is additive, not just being strictly neutral. Others will think differently.
It may not be the goal, but it is always the result.
The difference in tone between instruments is the harmonic content the instrument adds to the fundamental. I believe the flute is the nearest to a pure tone and the characteristic sound of an oboe is because it adds quite a lot of 5th harmonic (IIRC it is decades since I studied this).
The differences in timbre between different violins, for example, or violinists is due to the different levels of harmonics, also known as overtones, added to the fundamental by the body of the instrument or the way it is held and bowed.
This means that adding harmonics will definitely change the timbre and all SETs add harmonics since the basic circuit is not sufficiently linear to avoid doing so.
I quite enjoy the sound of SET amps, but I know they are rose tinting the sound.
Does that mean it is a used car salesman has given the best explanation or that he has has the same opinion as you?
It is not open to discussion that SETs produce more distortion than any other type of amp, and most of them have an uneven frequency response due to poor speaker impedance matching. That is fact.
What is open to discussion is whether people like SETs because of this added distortion or not. My interpretation of the information is definitely yes. I have never seen a cogent disavowal, though I have read page after page of discussions thereon.
HI Frank, Mike did not give any explanation, his system sounds awesome though. He uses Dartzeels. Btw, I do agree with you about SET and poor speaker impedance matching - I am surprised to see the kind of speakers people use SETs on, and the problems are easy to hear, but I do like them on some horns. The best I heard the Animas - as did most - were on the expensive Trafomatics at Munich this year, but it was a one-off amp the guy created, priced at some 120k.
It's very important to note the difference between THD and relative amount of harmonics.
THD is a technical measurement which gives rough idea how linear a component is but it doesn't tell much how it sounds like.
Harmonics and their relative amounts needs to be inspected to relate measurement and "real life"
Like you said a flute would sound like oboe if level of 5th harmonic (lets just say 3%) in amplifier (amp 1) would match that of natural sound of oboe. However another amplifier (amp 2) with equal amount (3%) of second harmonic would not make flute to sound like oboe at all. How would it sound then? I can't answer that but generally 2nd harmonic is considered as pleasant and thus might not be so critical at all and amp 2 would be greatly preferred over amp 1 as source of natural sound even though they both are "technically" equally "good".
What's really interesting is which amounts of distortion and what kind of relative distribution between harmonics is acceptable or even maybe preferable.
Many tube amps "excell" in higher even harmonics and relatively minor amount of odd harmonics. Maybe bit of "natural" distortion adds to close miked dry studio recordings
I agree that your first point is not open to discussion and is essentially fact.
What is open to discussion though is not what you have stated. What is open to discussion is the audibility of the distortion that SETs make vs. the audibility of the distortion that is made by other kinds of amplification types and it's detrimental impact on sound quality.
I do not believe there is such a thing as "euphonic" distortion. All distortion degrades. What has been clear though from about 60+ years of work is that not all distortion is created equal and its impact on audibility is exponentially connected to the order of the harmonic. The higher the order, the more objectionable the sound and the less it is masked from our ear/brain. Our ear/brain masks harmonics close to the fundamental so that up to fairly high levels they are inaudible. Content matters more than quantity. The question is where are those lines crossed.
It's very important to note the difference between THD and relative amount of harmonics.
THD is a technical measurement which gives rough idea how linear a component is but it doesn't tell much how it sounds like.
Harmonics and their relative amounts needs to be inspected to relate measurement and "real life"
Like you said a flute would sound like oboe if level of 5th harmonic (lets just say 3%) in amplifier (amp 1) would match that of natural sound of oboe. However another amplifier (amp 2) with equal amount (3%) of second harmonic would not make flute to sound like oboe at all. How would it sound then? I can't answer that but generally 2nd harmonic is considered as pleasant and thus might not be so critical at all and amp 2 would be greatly preferred over amp 1 as source of natural sound even though they both are "technically" equally "good".
What's really interesting is which amounts of distortion and what kind of relative distribution between harmonics is acceptable or even maybe preferable.
Many tube amps "excell" in higher even harmonics and relatively minor amount of odd harmonics. Maybe bit of "natural" distortion adds to close miked dry studio recordings
I do understand the "difference" between thd and relative amount of harmonics. If an amp has audible levels of thd it is definitely adding to the harmonic structure of the instrumental timbre. I have read loads of opinion pieces about which harmonics are unpleasant and which not, but that does not change the fact that SET amps have a sufficient magnitude of harmonic distortion to change the instrumental timbre, particularly when pushed.
I have been reading about even order harmonics = nice and odd harmonics = nasty for decades.
This is where I disagree with you. Some distortion is harsh, some euphonic. SET amps produce lots of distortion but usually sound nice therefore the distortion they are producing is euphonic. If the distortion level is low enough it will effect the sound less, harsh distortion will always be objectionable.
Harmonic distortion must change the timbre of instruments.
The idea that there is some magic about SETs which makes them sound nice despite being non linear has made a renaissance, I don't buy it and I have never seen a convincing hypothesis as to why such magic could exist.
I am still convinced that people like SETs because of their distortion characteristic is changing the sound to their taste. I see nothing wrong with making such a choice btw.
OK!
IMHO you can not ignore the comparison with other amplifiers when debating distortions. Even solid state amplifiers having very low distortion figures sound quite different from each other - probably by similar reasons that SET sound different from other type of amplifiers.
What are we exactly calling SET distortion? IMHO just the easily visible part of the iceberg, but not that responsible for the specific sound of SETs. IMHO each topology has its sound signature, people love good SETs because it does not have the signature of the pushpull.
I agree with Jean Hiraga when he says that more than quantity it is the quality.
This is why for SET use, all I've been pointing out is that it is important to use very efficient speakers with benign loads. Distortion will be quite low. I think a lot of the "SETributes" are caused by running them at higher power levels.
ALL amplifiers distort when pushed to the limit. It is hockey stick and each will have a different sound in that region.
If you stay well below that region, you will have a heck of a time demonstrating your opinion to be correct in a provable manner. No two subjectivists will describe the sound of two amps being different the same. And no objectivist will give you time of day by simply asserting that without some repeatable experiment done without bias.
In that regard, you can't start with an unprovable assumption to arrive at another conclusion you insist is true. First you have to work on the former.
What is considered to be efficient? What is considered to be a benign load?
Asking because we drove a 4/6ohm Vandersteen with an 87db sensitivity without any issues with distortion whatsoever
Driving is different from the speaker having the same oomph, mid bass, bass, drive, soundstage - some speakers come alive withe right muscle and sound lifeless but pleasant when driven be SETs. Now, I have no idea what power and control you used on the Vandy, but I have seen an AR 250 struggle to drive the Vandy 7 (83 db), and was acknowledged by the owner who was then looking for a change of amps.
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