Single or dual differential?

[SY]

I think it was whatzhisname at SWTP who first woke me up to this folly.

Dan Meyer?

In any case, it's pretty easy to get the amp-induced harmonics an order of magnitude lower than the audibility numbers being bandied about. Topology is an important factor, but as PRR has pointed out, it's just one factor. If we're designing for ultra-low distortion figures, well, all of this becomes important. If we're doing something easier, like merely designing a box of gain that cannot be detected by ear, we are free to forget about the mice and concentrate on the elephants marching around in the room.

[bocka]

.

What does seem to matter is getting the spectrum to slope steeply, and/or get it well below noise level.

I highly agree with this statement.

How about a harmonic weighting factor of: A=(n-1)!/2

John,

can you make this formula a little bit clearer to me? It looks nice, but I don't know where to start. Is second harmonic n=2? And what do you think is the max. amount of k2?

In my opinion there are several other important things.
The following statements are just an assumption:

1. The higher the output voltage the higher the distortion may be
2. Distortion should be independant from the load
3. Reversed error spectrum (higher output voltage/power) with decresed distortion is bad. This is typical for many class AB-amps.
4. The higher the output voltage the more higher harmonics may be present in the spectrum
5. Distortion should be independant from frequency
6. Distortion spectrum should not vary when two or more signals appear
7. With coupled rf-noise the the input distortion spectrum and levels should not vary

It's just my opinon but I think this therory is more complex than only viewin' to one (technical and therefore simplified!) signal

[john curl]

How about A[H(n)]=amplitude of the individual harmonics (n) The [ ! ] is a factorial.

[hitsware]

I think NP makes a good point in one of his papers for the viability of the single ended approach. (He's speaking of output stages, but the same should hold true throughout the chain):
Sound is single ended I.E. we don't live at 0 p.s.i. The natural state of an acoustic wave is to vary around a positive value rather than to be bipolar...........mike

[PMA]

(Factorial)

[PMA]

Originally posted by hitsware
I think NP makes a good point in one of his papers for the viability of the single ended approach. (He's speaking of output stages, but the same should hold true throughout the chain):
Sound is single ended I.E. we don't live at 0 p.s.i. The natural state of an acoustic wave is to vary around a positive value rather than to be bipolar...........mike

But this has already been received by the microphone, you do not need to add any more non-symmetrical acoustic pressure distortion

[bocka]

The problem is we cannot build a distortion-free amp (with only one exception...)

In this way we should keep the audible distortion level below the hearing threshold level. Unfortunaltely no one know exactly what this means. So we use static signals in order to map the "audible quality" to measurable signals...

[hitsware]

>But this has already been received by the microphone, you do not need to add any more non-symmetrical acoustic pressure distortion

But for the electronic device to act in an 'airlike' manner, should it not run the same way. Granted sort of metaphysical but ??????

[PMA]

Originally posted by bocka
The problem is we cannot build a distortion-free amp (with only one exception...)

In this way we should keep the audible distortion level below the hearing threshold level. Unfortunaltely no one know exactly what this means. So we use static signals in order to map the "audible quality" to measurable signals...

Agree, we should examine dynamic spectral distortions and and intermodulations ....

[bocka]

Agree, we should examine dynamic spectral distortions and and intermodulations ....

Yes, I think so, but I fear it's a multi-dimensional problem...

Spectral distortions and and intermodulations at nearly every frequency, aly load, any level. It's gettig (too?) scientific.