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Do you have to have that fat, lush, tube character to have the palpable, liquid texture, or can a very neutral amp like an RM-9, ARC, or VTL have neutral character and tight bass, but will be liquid?
Boy what a tangle of subjectiveness.
Follow Ups:
The 'rich' sound of tubes is usually the 2nd order. But that is not something a tube *has* to do- its a product of the topology of the circuit.
For example, if you want neutrality and detail without artificial lushness, the circuit should be entirely differential and balanced from input to output. In this way all even orders will cancel with each succeeding stage. All that remains is the 3rd. If its fully differential, the 5th and above will not be showing up.
However, if you mix single-ended with balanced as in a Stereo 70 or similar, you will get a 5th harmonic. And of course in a single-ended circuit the 2nd predominates, followed by the 3rd and 4th (with the remaining harmonics showing up once the amp puts out power over about 25-33%).
Of course you can use feedback to reduce harmonic distortions, but you will find that it makes the amplifier brighter as it will add slight amounts of odd ordered harmonics. The ear uses these harmonics to determining how loud a sound is, so there is a good argument for finding a way to get rid of distortion without feedback.
So you can see that topology is the main thing that determines the distortion and the resulting tonal character (if you've not sorted it out by now, the ear hears distortion as tonality).
The simple fact is you can have a tube circuit that is neutral and musical, without being overly lush, unless the music itself is lush.
I think it has more to do with excessive distortion in the bass due to poor output transformer design, which is why OTLs rarely sound like typical tube amps. It is also why very good transformer coupled amps are very expensive if you want this characteristic under control.
Just one thing I'd add Ralph - since ALL amplifying devices distort to some degree, much (most?) of a device's overall characteristic tone is determined by the distortion spectrum created by that device. And (this is personal experience only, YMMV!) I find most listeners prefer a distortion spectrum that is NOT exclusively odd-order products but instead a "waterfall" of even and odd orders, with each higher order lower in amplitude than its predecessor (i.e., 3rd is lower than 2nd, 4th is lower than 3rd, etc.).
Incidentally - despite the multiple loops and > 30db of total NFB the "McShaned" Citation II can be set up to have the "waterfall" distortion plot, yet no 5th order or higher is visible on my analyzer. If there is any it's lost in the noise, meaning it's down over 100-105 db or so, the limits of my test capability. I have seen this with my own eyes on my own test bench. I'm not saying no 5th order or higher products exist, I'm just saying they are so low in amplitude they are (again IMHO) not significant shapers of the amp's overall tone.
FWIW...
Its true that the higher odd orders are often difficult to measure! But that they are hard to measure is not the same as they are not there- and our ears, being tuned to pick them out, find them easily where our instruments struggle.
IOW, many things in engineering can be ignored once they become 'negligible'; but in the case of audio, odd-ordered harmonics can't, as our ears use them to determine volume- for them there literally is no 'negligible' value.
It is this aspect of human hearing that is why two amps with equal bandwidth can sound quite different- one bright and the other not (once both are driving a load that both amps are happy with...). It has entirely to do with odd ordered harmonic distortion, often of vanishingly small amounts.
I'm not sure what "liquidity" means, but I assume that it has something to do with ease and pleasure of listening. My Vacuum State RTP3 definitely has that, along with "palpability".
I don't have enough experience with other comparable preamps in my system to comment on its neutrality (except to say that it is tonally very similar to an ARC SP-11), but I gather it is widely acknowledged to have a very neutral balance.
The same goes for my push-pull 300B monoblocks, designed by Keven Kennedy.
Alex
Check out Lamm "ML" series SETs to have your cake, and eat it too!
"Your liver suffers dearly now for youthful magic moments...so rock on completely with some brand new components"
IMHO based on my study/work in the field the "liquidity" is predominantly a result of the amount of even order harmonic distortion produced - predominantly 2nd order.
For those who read all the misuse of the word "harmonic" on forums, harmonics are simply tones produced that are multiples of the fundamental. In other words, if you play a 1KHz tone you will also find tones at much lower levels at 2K, 3K, 4k, etc. If the number is an even number it is even-order distortion (2nd, 4th, etc.), if the number is even (3rd, 5th, etc.) it is odd-order distortion. Even order harmonics added to the fundamental sound warm and "musical"; odd-order harmonics added to the fundamental sound cold and shrill/harsh/etc. Harmonic distortion is the term used to describe it.
So it is clearly possible to have an amp that has extended frequency range and also has a distortion signature that is mostly 2nd order - meaning a warm "liquid" tone - but not have the rolled off top end that makes it "fat/rolled off" and "lush".
All instruments produce a fundemental tone and overtones or harmonics which give the characteristic tone of the instrument. These overtones are not distortions but are produced by the instrument. However in reproducing an instrument if the overtones are not reproduced in the original amplitude and phase relationships you would then have harmonic distortions. You can also have im distortions which are harmonics produced by combining two or more fundementals. The correct reproduction of harmonics is absolutely necessary for accurate reproduction of sound.
Alan
but the complex 'shape' of the attack or starting transient, which fully characterises the instrument. That is, we know it's an oboe very quickly, before the sustain happens.The next most important to our hearing and affective systems is the decay, and the continuous tone and ITS harmonics comes last.
Note also that a large number of instruments don't do continuous tones, no sustain, Pianos, all percussion, and harpsichords. But they still have characteristic tone and expression, and so do their players.
The ability to retain the relationship of the fundamental and harmonics in the starting transient wave form is very important, and if that is right steady state behaviour will also be fine IME.
Matching rise and settling times in the recording and reproduction chain are also important. One of the reasons why our rooms and recording venues are important.
Good output transformers and matched speakers are vital.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
Edits: 08/15/12
"All instruments produce a fundemental tone and overtones or harmonics which give the characteristic tone of the instrument"
Right - but if the tones reproduced by an amp (let's say) weren't part of what was fed into that amp then they are distortion. If they are multiples of the fundamental OR the overtones that were input into the amp then they are harmonic distortion.
"im distortions which are harmonics"
Not exactly, at least IMHO....
Intermodulation distortion is is new tones created by the sum and/or difference of two or more other tones - not just at harmonic frequencies of either original tone, but also at the sum and difference frequencies of the original tones AND at multiples of those sum and difference frequencies. The multiples are harmonics - but since a new IM generated tone can be lower in frequency than either of the original tones it can't be defined as a multiple of the original tone (unless your multiplier is less than 1, which gets into a real grey area, at least for me!).
But this is a bit O/T - we totally agree that if the tone was not in the program material fed to the device then it is distortion - and some distortion is perceived differently than others. Some is perceived as musical and pleasant, some as amusical and unpleasant.
Modern circuits and components can maximise those advantages. Often not mentioned among the others is that truly large PSU storage is easier for valve amps than for SS, even baby classics.
My rebuilt / modified LEAK Stereo 20 amps don't sound warm or thick at all. BIG stiff PSUs were an intended part of both rebuilds. 20WPC 20-20k in pentode instead of a bit over 10 wpc in UL, using 7189/EL84M valves. Review here at AA.
Mine sound nice in ways that few modern SS amps, esp. for the cost, could hope to approach. If the recording is BRIGHT and a multi-close miked mono mix-down you'll sure know, but all the valve expression and nuance stuff still happens, and on real stereo ..., wow!!!.
Very quiet, transparent, and capable of letting you hear an Aphex Aural exciter doing its thing [ or its worst? :-) ] Even the bass has SLAMM.
In OEM / old stored state? Boinggy and thuddily slow in the bass, and noisy including burrps and farts, and just-audible hum.
IMO many current tube power amps still have smallish power supplies and use minimum rating R's , .... ! Some still run the OPT stage too hard.
I didn't get into tubes for the warm rolled off limited bass sound nor the PSU limitations known as sag to electric guitarists, and loved by many of them as an effect, but to let them get out of the way, like they can given the right 'systems support.'
If you have speaker's and a set-up you are know is optimised, you need to listen to some amps, including some optimised classics.
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
You can have a relatively neutral tonal balance and still have liquidity. Warmth isn't really related to liquidity or "wetness".
Jack
"Boy what a tangle of subjectiveness"
But your self-assessment of your own post gave me a laugh.
Thanks!
I didn't find the ARC VT-100 & 200 to be very liquid at all. The VTL amps I haven't spent enough "quality time" with to have a strong opinion. It has been to long since I've heard either a RM-9 or a RM-200 to reliably comment. I don't, however, remember the RM-9 being what I'd characterize as "very neutral."To my ears the Atma-Sphere do the best job among the tube and hybrid amps I've heard of retaining tube virtues (liquidity, palpability) while getting rid of tube distortions/colorations (fat, lush, warm).
Edits: 08/04/12
It's been a long time since I've owned ARC amps but here is what I recall.
The ARC VT100mkII sounded very powerful and robust in the mids on down. It had a pretty nice 'full bodied' sound but not quite as rich as a pair of Cary amps that also owned. It was indeed less 'colored' but still very much to my liking. I tried it with KT88s and 6550 tubes but went back to 6550's as they sounded more transparent to me.
The smaller ARC VT50 was a different story. It seemed a little lean in the mids and as expected not as dynamic as it's big brother. I really liked the VT100mkII but I couldn't get the midrange that I wanted from the VT50. I tried KT88's and 6550 tubes in it but neither got me there.
Can you describe what you're not hearing in the ARC VT100 that you like in the VTL and Atma-Sphere amps? I've never owned either of these brands. The closest to the VTL would be the pair of Manley amps I once owned.
The period when I was listening to these amps in known rooms on an almost daily basis is now ten to twelve years in the past so the vagaries of memory are in play.
The short version is that I thought the sound of the VT-100II and VT-200II was too close the sound of good solid state amps to justify the heat and cost of maintenance they involved. The sound was an extremely good reproduction but that sense of palpability or the suspension of disbelief was missing. The Atma-Sphere amps could deliver that without the euphonic distortions of many tube amps. If anything the Atma-Sphere amps in question (M-60 II.2 & MA-1 II.2) were slightly lean from the mid-bass down, they didn't embroider the very pretty but ultimately false sound that many tube amps produce.
The speakers used were primarily Magnepans, SF Amati Homage, Spendor SP-1/2 and more briefly the Vandersteen 5, Green Mountain Continuum 1.5i, the original Wilson Sophia and the Watt/Puppy 6.0.
I've never heard the big Manleys so I can't draw a comparison to them.
The Atma-Sphere M-60s are somewhat limited in what speakers they are truly happy driving. They are not so limited as most SETs but you still want at least a medium efficiency speaker whose impedance doesn't drop below 6 ohms and is typically at or above 8 ohms. The MA-1s, in my experience, are much more flexible although higher impedance loads are still preferred and they don't pair well with speakers that drop much below 4 ohms unless you use the Speltz autoformers. The Atma-Sphere amps are IMO the best tube amps I've heard, and perhaps the best amps period, that I could reasonably hope to afford but I haven't heard the ARC REF150 and several other relatively new possible contenders.
I always wanted to say that ARC's "house sound" is solid state sounding. I didn't want to get flamed from their many fans for saying it, I admire your courage.
I also want to add that Bob Carver was advertizing at one point, that he could make the same model amp sound like a typical golden age tube amp, or if the buyer preferred, a modern sounding tube amp. I think we can safely agree with Ralph, that it is the circuitry that determines the ultimate character of the amp. I imagine everyone except me, knew that already. That's from a guy that is an inveterate tube roller.
Steve
Where is Bambi when we need him?
I don't think the early ARC house sound was at all solid state sounding although it was more incisive and neutral than C-J products of the same era.
IMO it turned slightly more SS sounding in the mid to late '80s but still held on a fair chunk of tube virtues. You almost have to go product by product from this point on as the house sound was something of a moving target. Somewhere around 2000 the house sound took a definite turn toward SS IMO but I understand that the latest generation restores some tube qualities.
The driver tubes on Ralph's amps are (or at least were) somewhat tube rolling amenable.
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