More audiophoolery: discrete op-amps better than ICs!

[denelec]

But any claim of better sound must be validated in a "double blind trial".
If you can't tell the difference, it doesn't exist.

How often do "better sound" claims are said to be validated by a double blind trial? 

There's a lot of placebo effect and cognitive dissonance going on with audio equipments.

[SeanB]

Major advantage of the IC amplifier is that if you make 10k of them, then you can do very fast and simple testing to ensure that all are within the parameters desired, and you can get low noise, good gain and very similar performance with almost unmeasurable difference in the performance between any randomly selected units.

The discrete amplifier requires adjustment and selection of parts that have to be matched for each unit, and making 100 will take longer than what it takes to have the 10k of integrated circuits go from raw metallic silicon to finished, packaged, labelled and tested units ready to ship out.

The IC makes it near trivial to ensure matching, and this will hold true over a larger range than for any discrete transistor in almost every case. Unless you cut them from the die as a unit and keep them bonded together until casing they will vary. In that case you might as well use an integrated circuit differential pair, or a IC array.

[dannyf]

But any claim of better sound must be validated in a "double blind trial".

Why?

If you can't tell the difference, it doesn't exist.

If a tree fell in the forest but you didn't hear it, did the tree fall?
If someone committed a crime but you didn't see it, did he commit the crime?
....

[dannyf]

If you're old enough, vacuum tubes amplifiers will deliver the best sound to your ears.

Not sure if they deliver the best sound but tubes do deliver better than than solid state amplifiers when over-driven.

That is well understood.

[GreyWoolfe]

If that cable got my wife pregnant, I would be suing everyone in sight since my wife has had a full hysterectomy.  Then, I would make Jerry Springer pay us 10 million dollars to come on his show to tell our story.  I bet we could be even bigger reality TV stars than Snooki and Kim Kardashian!

[denelec]

But any claim of better sound must be validated in a "double blind trial".

Why?

Because of the placebo effect. If someone expect an equipment to sound better, it probably will to his ears.

And the trial must include a statistically significant number of participants.

But the subject is complex.  For some people, lower distortion, lower noise and higher dynamic range doesn't necessarily means better sound.  "Better" for someone may mean "worse" for another.

[denelec]

If you can't tell the difference, it doesn't exist.

If a tree fell in the forest but you didn't hear it, did the tree fall?
If someone committed a crime but you didn't see it, did he commit the crime?
....

I should have said: "It doesn't matter."
Ideally, when choosing between several audio equipments, you should listen to each without knowing which one you are listening to. If you can't tell the difference between two equipments, then you should base your choice on other criteria.

[dannyf]

Because of the placebo effect.

So?

[/quote]And the trial must include a statistically significant number of participants.[/quote]

"must"?

[Circlotron]

If you're old enough, vacuum tubes amplifiers will deliver the best sound to your ears.
The best electric guitars amps are made with tubes...

With a musical instrument amplifier the situation is different to a hifi amp. A solid state guitar amp for example sounds much the same as the volume goes up and up till finally (and suddenly) it hits the brick wall of hard clipping. Truckloads of negative feedback add to this sudden onset of grating distortion and clipping. With a vacuum tube amp, generally the distortion climbs gradually with the volume, and then right at the end it gets worse(?) quicker, but nowhere near as sudden as with a solid state amp.

The benefit of this is that the musician can use this gradual drift into distortion as an extra dimension of expression, much the same as a softly played piano has a gentle sound, but a firmly played piano has a much more urgent sound because of a different harmonic structure. The amp contributes to the timbre of the sound at the whims of the artist. Definitely desirable with a musical instrument. Really bad news for a hifi. It's horses for courses. Each device has it's own benefits and drawbacks.

[Galenbo]

But the subject is complex.  For some people, lower distortion, lower noise and higher dynamic range doesn't necessarily means better sound.  "Better" for someone may mean "worse" for another.

The subject isn't complex, but the uninformed religious fundamentalists are.

"better sound" is simply how close output and input signals are related. This can be measured and compared by people who are schooled to do that. The other ones can go discuss about their emotions, what they say is important for psychiatrists, not for technicians.

[David Hess]

I would submit that with sufficient degenerative resistors, a random pair of transistors is practically no different from a well matched pair of transistors, discrete or integrated, in an opamp.

Degeneration will lower gain and increase noise significantly.  They go to great lengths to lower the Rbb and Rbe resistance in low noise differential pairs.  Large area discrete transistors may be even lower noise but require higher currents.

[David Hess]

A discrete design may have the advantage of preventing thermal feedback between the output and input transistors which among other things limits open loop gain but the same thing may be accomplished by adding a discrete buffer stage to the output of an integrated operational amplifier.  This is especially the case when an audio design may use low impedance feedback networks to keep noise down.

I would be more impressed in a discrete design using integrated matched input transistors like the SSM2220/SSM2212 or LSK389/LSK489

[Bassman59]

That sound went 50 times through a 5532 before the recording was made.

THIS.

[Bassman59]

That's how far down these guys have their heads buried in the sand.

Their heads are buried somewhere else, much darker.

[dannyf]

Degeneration will lower gain and increase noise significantly.

Lowering gain would be a good thing for audio amplification.

As to increasing noise significantly: how significant is your "significantly"? is it 0.1db significantly or is it 10db significantly? is the noise in an amp going from -300db to -200db due to degeneration?

One person's "significantly" can differ significantly from another person's "significantly".

[T3sl4co1l]

I would submit that with sufficient degenerative resistors, a random pair of transistors is practically no different from a well matched pair of transistors, discrete or integrated, in an opamp.

Degeneration will lower gain and increase noise significantly.  They go to great lengths to lower the Rbb and Rbe resistance in low noise differential pairs.  Large area discrete transistors may be even lower noise but require higher currents.

Degeneration doesn't need to be resistive, see "noiseless feedback" for example.

Also, to be clear: dynamic range will drop (gain / noise ratio) for increased degeneration, but total noise (output v_n) will drop.  I think I'd want to run some numbers before making a more precise statement, like how dynamic range varies over chained stages, at different gain settings (and for different approaches, resistive / noiseless feedback, local vs. global, etc.), but I seem to recall it's best for fairly small ratios (a gain of 3 or thereabouts being just enough to get the first stage out of the noise floor of the subsequent stages, so signal grows exponentially while noise grows additively for N stages).  Which is also best for bandwidth.

Tim

[VK5RC]

One interesting low noise pre-amp I built was using paralleled op Amps from a design by Self, by paralleling the noise reduces by the sq-rt 2. IIRC.

[daqq]

Discrete-better-than-integrated seems to be a belief shared by the audionuttery community:

http://www.6moons.com/audioreviews/totaldac3/1.html

As I see it, a DAC is made up from a load of precision resistors. Are they actually being driven by the 74HC574 next to them? Even if that is not the case I wonder how they'd achieve 24 bit resistor driver matching...

[dannyf]

a DAC is made up from a load of precision resistors.

Depending on the specific topology. Many are - most were, but many aren't.

[alpaca]

This stuff is quite normal in the world of audio woo-woo. You REALLY want to see nutso? Try this:

http://www.machinadynamica.com

[calexanian]

I love this sort of nonsense and messing with the people who believe it! I want to make the suggestion to Wendell and Lenora at evil mad scientist to make a discrete 741 kit like they make the 555 kit. They already have the legs and such! Good learning type kit.

[dannyf]

You REALLY want to see nutso?

You are trying to bring too much "rationality" to human comprehension.

A few points for you to consider:

1) the fact that something is unlikely to be useful doesn't mean it is not useful: what's "useful" is highly subjective and dependent on the individual perception / definition of "use" and knowledge at that point in time and the context. A bottle of water is useless for a person drowning but a life saver for the same individual dying of thirst in the middle of a dessert.

2) the fact that something is not explainable today doesn't mean it is explainable: our knowledge will advance over time and a silly mystery today may be common knowledge tomorrow.

3) individual freedom vs. imposition of "intelligence" onto others: however rationale / optimal you may think your position is, you have no right to project it onto others. Everyone of us should be free to make our own decisions, however silly it may seem to you.

4) "religionize" science: science is ***one*** of many possible ways to understand our world. The key to science is the presumed assumption that science as we know it today is always wrong: something better and more comprehensive will come along tomorrow and revolutionize our understanding.

To follow that spirit of science, you have to keep an open mind - what's "un-scientific" today may be "scientific" tomorrow, and vice versa, however unlikely.

What you often see, unfortunately, are "scientists" who treat scientific discoveries with absolutism: what's science today will always be true and what's not science today will never be science.

By doing that, they have violated the fundamentals of science.

[miguelvp]

What you often see, unfortunately, are "scientists" who treat scientific discoveries with absolutism: what's science today will always be true and what's not science today will never be science.

By doing that, they have violated the fundamentals of science.

You should watch or even just listen to MindWalk 6 minutes into this part about a view of science as a religion:



Edit: hmnm the time set in the link is not working, start at 6 minutes exactly.


Actually you should watch the whole movie, it's pretty good for thinkers.

[ConKbot]

One interesting low noise pre-amp I built was using paralleled op Amps from a design by Self, by paralleling the noise reduces by the sq-rt 2. IIRC.

Shhh, dont mention paralleling, you'll bring around stuff like


Paralleling DAC IC's to sound gooder.

[wraper]

Discrete-better-than-integrated seems to be a belief shared by the audionuttery community:

http://www.6moons.com/audioreviews/totaldac3/1.html

As I see it, a DAC is made up from a load of precision resistors. Are they actually being driven by the 74HC574 next to them? Even if that is not the case I wonder how they'd achieve 24 bit resistor driver matching...

I really doubt that this dac can do even 12-13 bit with monotonicity of output. Not to say that analog and digital is highly mixed all over the board.