[avahifi]

I have no clue about "voicing" an amplifier.  It is NOT a musical instrument.  It is not supposed to "sound good".

The best it can do is to not screw up the information presented at its inputs and drive whatever load is connected to it without interacting with or being modified by the load.

The more causes of non-linearities we can identify and fix (without the fix making something else worse ) the more people seem to appreciate the performance of our amplifiers in their audio systems.

We will leave "voicing" to trumpets and tubas and such, and keep doing basic evaluation of circuit electronics.

For example, did you know that a capacitor as a power supply feed likely will have an impedance as high as several hundred ohms as some frequencies, and the circuit formed by the inductance of the leads and feeds to the active devices and the capacitor will have many underdamped resonances that can be mathematically modeled?  That means at some frequencies, you run out of power supply, and you also generate an error signal across that impedance.

A shunt zener regulated supply will take that impedance down to about ten ohms, an active ultra wide band analog regulator will take it down to under one ohm.

Or, the error signal you can generate across a passive supply, even a battery, can be hundreds of times as big as with a carefully designed active analog regulator.  Can you hear the difference?

Well, can anyone hear the difference between our Transcendence hybrid preamps of ten years ago and a new Ultra?

We did not spend any time "voicing", only refining our engineering knowledge and the application of that.

Frank Van Alstine

[martyo]

Since Frank kind of brought it up, I've been wanting to ask the question "has anyone gone from a super pas 3i to any of the Transendence or Ultra pre amps.
I'm wondering what kind of characteristics i have to look forward to when I can upgrade. That was Bob Carver that said that about the symphony and he did talk as if he had a certain sound in mind when he designed products. I own the Platinums and love them, however when I replaced the C16 pre amp with the 3i, in addition to air and definition and soundstage and quickness.........the whole "signature" of the sound changed and when I borrowed my brothers 550 for a month again, in addition to all the positives that are used with AVA equipment, the whole sound was very different. Frank talks about letting the real source thru and Mr. Carver talks at aiming for a particular sound. In my own personal experience it seems to me at least some designers might prefer certain colorations.

martyo

[martyo]

regarding the last post, that was exchanging a Carver tfm75 with the 550.

[Kevin Haskins]

What Frank said...   

[Bob Reynolds]

Not wanting to offend anyone, but my understanding is that the "debate" is not as the original poster suggests. Saying that all amps (or preamps or CD players or DACs) sound the same is an over simplification of the objectivist's stance.

For example, regarding amps there are a few qualifiers: 1) high input impedance, 2) low output impedance, 3) reasonably flat frequency response, 4) applied within its power rating (i.e., not near clipping) and 5) level matched within 0.1dB.

Also, in the ABX trials there are no time limits. Take as long as you wish. The idea is that you take as long as necessary to characterize amp A and amp B. If you believe they sound different, then you should be able to identify X as amp A or X as amp B.

Regarding Frank's comment about the ABX device. Surely that is not the only way such a device is constructed. There is no reason that the inputs aren't switched, as well as, the outputs, i.e., the two amps are completely isolated from each other. I've read that the participants agree before the trials begin that the ABX device is transparent.

The methodology seems sound to me. It removes the placebo effect and is accepted in other branches of applied science.

I think a good way of viewing the objectivists are as consumer advocates. We have "truth in advertising" laws and a department of the federal government to enforce them. We all benefit from this in all aspects of our daily lives. Consumer advocates aren't out to hurt businesses, but to protect the public (not only safety, but from fraud).

I have recently conducted a sighted level matched comparison between two preamps. It was an interesting exercise and I recommend it to anyone doing a home audition of any piece of electronics.

[avahifi]

My goodness, I sold someone one of our amplifiers based upon what it looked like?   

I must have taken too many pain pills that day.

Regarding switching inputs in an ABX test setup, normally switching inputs to an amplifier while it is turned on results in a very large crashing transient, not recommended.  And of course if the ground sides are not switched too, to eliminate this possibility, then the interaction described earlier still occurs on the ground side of the common connections.

Come on now folks, did you ever hear a "scientific" ABX test session in which anything really sounded really good at all?  Of course not, the sum of the distortions of two amplifiers is always worse than the problems with any one of them separately.

Do all amplifiers sound the same?  Of course not.  Otherwise I would not have spent my life trying to do better yet.  Those who rely on scientific methods that do not cover all the basis are overlooking the runner stealing home.  No hits, no errors, but you still lost, even though you will not admit it.

Cables and interconnects:  We can measure their effects on equipment that you (and we) can hear, but it is not a measure of "goodness" in the cables, it is simply the effect of how much the load that cable represents changes the linearity of the equipment it is attached to.  The tests are easy to run, square wave generator and dual trace scope needed. 

We are astonished to see how little real curiosity there is out there regarding these effects.  Seems like everyone would rather blather about the sound of their pet cables than actually test them a bit to understand what is really happening.

Frank Van Alstine

[Zheeeem]

>>We are astonished to see how little real curiosity there is out there regarding these effects. <<

Um.  Why should there be curiousity.  If cable effect is, indeed, simply the effect on active components because of a changed load (and I'm well and truly convinced that it is), then there's no real need for curiousity.  Or rather, there's no need for curiousity beyond what resistors, capacitors and inductors "normally" do in an audio circuit.

There is, however, abundant pseudo-curiousity in the form of explanations about how presumably irrelevant physical phenomena impart marvellous new properties to, uhhhhhhhh, wires.

I dunno.  Sometimes I think maybe I'm not curious enough.  I've never tried $1,800 interconnects or $5,000 speaker wires in my system.  Hell, I've never even tried after market power cords of any type.  WRT the latter, nobody has been able to explain satisfactorily how they can possibly make any difference at all, and WRT the former I cannot quite figure out how swapping wires is anything more than a random event in terms of "improving" sound.  Heck, I'm not even curious about intelligent chips, quantum line filters, mpingo disks, shakhti stones, brilliant pebbles, clever clocks, rainbow foil, cable elevators or dozens (hundreds?) of other things marketed to make my system sound better.

But lest you think I have no curiousity at all, this weekend I will employ what little I have to find the best placement for my new speakers (VMPS RM30M) and work on room treatment to try to get the most out of them.  Oh.  And I'm also very curious about a wide variety of musical performances.

[Zheeeem]

A wire has resistance, capacitance and inductance.  Hence, any wire is an oscillator.  This oscillation should be out of the 20-20,000 audio bandwidth.  But equipment may be sensitive to having even an out-of-audio-bandwidth oscillator in series.  If it is sensitive, then stuffing this particular oscillator into the circuit may provide feedback that has an effect on the active components.

Frank had some good Audio Basics articles on wires.  You might scan his index.

[Wayner]

I just hook stuff together and listen to vinyl. By the way, I just finished coating the inside of my AR turntable with plasticlay and that did more that any cable could. 

[mark funk]

cables,cables,cables! The biggest things I did to my set other then all AVA is make my room dead! and clay all may speakers!  The only time I heard any diffrants in cables was when I went from that fine braided high capacitance  speaker wire to Belben 10ga. wire. Ask Martyo about before and after clay and room treatment!

[Horizons]

I have participated in informal tests like these and the results usually make the tweeks cringe.

So funny to witness them state adjectives like "STAGGERING, STUNNING, DRAMATIC, INCREDIBLE, etc."  Then only minutes later be unable to pick between low-fi, mid-fi, and high end components, wires, etc.

The emperor has no clothes but many people make a good living off of these high-end threads.

http://www.matrixhifi.com/contenedor_ppec_eng.htm

[eico1]

A wire has resistance, capacitance and inductance.  Hence, any wire is an oscillator. 

wouldn't that be more like a lowpass filter?

steve

[Russell Dawkins]

I think all amps do sound the same. So do all CD players, turntables, preamps, and speakers. Oh, and microphones - music, too, for that matter!

Not.

One problem in attempting to understand why amps sound different is that measurements seem to have precious little correlation to what we hear.
In an attempt to come to grips with this glaring anomaly HFN of England did some analysis of there own, their conclusion being that the only measurable characteristics that seemed to relate to subjective impressions were the 1) the nature of the amp's recovery from clipping and 2) (strangely) the degree to which the amp's performance was affected by RF contamination of the source signal.

I saw this link on the interesting Dared pages:

http://www.daredtube.com/pages/ampfile%20list.HTM

In it, a rare attempt is made to find logic in the association between measured data for amplifiers and subjective sound quality. It has been pointed out before that there seems to be very little in the way of correlation between the two, suggesting that either the wrong things are being measured, or the results are being mis-interpreted.

Some of this is, frankly, beyond me. It is interesting to note that an amp that does very well according to the criteria outlined in this paper is the Cary CAD 805 monoblock that was the subject of the famous 1994 Stereophile cover showing it and a Krell, saying, famously, "If one of these amps is right, the other is wrong!"

Perhaps someone with some real engineering understanding could weigh in on whether this paper seems reasonable or not.

[srayle]

Do all amps sound the same?

Nah. No way. If you must be aqsking this question, well, the answer will not be available to you
anyway, so just buy something 'quality' so that when you think you're bored, get something elase.
At this point in this "hobby" (hahahahahahahaha!) if you still can't tell if it makes a difference, keep the
damn Rotel or Pioneer and go the to some nice destinations and drop thy cash on some fine food and wine...
(ah, now wine, there's another one for ya).

Cheers!,

Cheers!,

Cheers,
Chears,
CHeArrss,

sTeVE