TC Electronics Switch amp

Status
Not open for further replies.
Jump to Latest
#41
But that's not ICEpower modules, these are other technologies for other purposes 🙂 (and maybe another sign showing that ICEpower modules are slowly dying and becoming a less interesting product).

Anyway, nearly all of the amplifiers discussed are based on the "phase shift oscillator" physical principle, something quite hard to patent, I think. Many poles and zeros may be added to the feedback loop in different patented fashions, but it's still a feedback loop arranged to get a phase shift oscillator.

I could add an extra pole or zero, or an extra path, even if it's useless, and get my own patent 😀
 
Last edited:
#42
TO: KURT VON KUBIK
hi,
Maybe my English is not good.
not in my nature to speak ill of others.
I just wanted to point out that I can not find any new technology among large firms
Instead I find much talent on people without means, are able to mortify.
we both know how important marketing, large companies play on this and not on persons valide.il result is what I said before .. everything old.
I probably own sell the patent for new psu for a great company.
personally I greatly admire what he said EVA!🙂
 
#45
I have no doubt that the future (imminent) will be digital-to-digital.
end of all the problems we are discussing.
high fidelity playback? not need ... sound instruments will only be digital.
in 2025 no longer useful amplifier. each receives directly on the brain.🙂
 
#47
Self-Oscillant Amp critical points?

Hi,
because I think the interesting subject matter yesterday, (FB loop).
I propose to discuss why self-oscillator is simple but not easy to get true audiophile performance? (measurements, THD vs-frequency, THD, sn / r, transient response, IMD response).

I think we tried many different solutions, comparator, DT, integration, Op-Amp.
according to you, where is the critical point of a simple self-oscillating amplifier?
would be interesting to discuss this, it clarifies many things.
 
#48
AP2 said:
Hi,
because I think the interesting subject matter yesterday, (FB loop).
I propose to discuss why self-oscillator is simple but not easy to get true audiophile performance? (measurements, THD vs-frequency, THD, sn / r, transient response, IMD response).

I think we tried many different solutions, comparator, DT, integration, Op-Amp.
according to you, where is the critical point of a simple self-oscillating amplifier?
would be interesting to discuss this, it clarifies many things.
Click to expand...

As far as I know there are several critical points in self oscilating amps.
I did not build one myself, but as already told, I´ve tried out some different designs, and two of those were IMHO superior designs.
Both of them had more than one FB loop, the ICEpower amp was the first one I tried which was rugged, stable and also reasonably well sounding, a bit polite perhaps, but remarkably free of resonance and colouration.
The TC works just as good, but its sound is IMHO more acurate and natural and even less colouration is present.

The 2 most important matters pointed out to me was layout and feedback.
I do also know that the linear part of the amplifier ought to be subject for attention i.e. opamps and their PSU´s.

The inner feedback loop should actually provide a very strickt control of the power conversion reducing its ensitivity to jitter dramaticly.
But the whole idea of using more than one FB loop origins in the problems of using just one. If FB is taken before the postfilter, you will not be able to correct unlinearities in the postfilter itself, making it sensitive to load.
Taking your FB signal outside the postfilter, you can correct unlinearities in the postfilter, but you cannot avoid degradation of performance due to phase shift in the filter itself.

The tripple loop system was made to take the advantages of the double loop system a step further, by reducing the problems in having a slow post filter audio FB loop in conjunction with an ultra fast pre filter high frequency FB loop.
This minimises most of the unwanted effects of the outputfilter, since feedback can now exceed the filtering frequencies.
To me this seems to be an indicator showing that the postfilter generally is a huge problem in class D amps, since the third loop is excactly minimising theese problems, and that you can hear with ease.

I find this solution both elegant and sophisticated, and the only reason it came about was, because LC Audio was aquired by TC electronic, and the designer did not like the single loop designs by Lars Christiansen.
And as a former employee in the R&D team @ ICEpower, he knew of both the upsides and downsides of ICE technology.

So now it is possible to obtain enormous dynamic range depending mostly on the quality of your buffer and the supplies for it, and an unbelievable dampingfactor. And as I said before, excactly that is what one remarks emidiately when listening.
 
#49
from : Kurt Von kubik

Taking your FB signal outside the postfilter, you can correct in the unlinearities
postfilter, but you can not avoid degradation of performance due to phase shift in the
filter itself.
-------------------------------------------------------------
yes,
You say right, post-loop filter is essential, but then where's the problem?
(leaving out important devices for now), it remains very simple diagram, suppose comparator, dt / logic stage and driver stage. all configurations in this company has many difficulties to enter good FB. (all amplifier would be perfect or the same performance).
Problem is in the stage pre-drive/drive architecture. all performances depends on it, crystal clear sound quality slew / rate etc..
B & O could not enter directly FB first stage of conversion because of the delay (total)
can not think of the sound driver as a step motor control.
example, suppose you change .. after comparator on Hypex, with traditional drive circuit you think it works the same? I remove entry-point of FB .. but back to the problem of other amp.🙂
vorrei provare un TC module, è possibile?
...Philips has had great intuition...🙂

I would try a TC module, is it possible?
Regards.
Sorry for my english
 
#50
AP2 said:
from : Kurt Von kubik

Taking your FB signal outside the postfilter, you can correct in the unlinearities
postfilter, but you can not avoid degradation of performance due to phase shift in the
filter itself.
-------------------------------------------------------------
yes,
You say right, post-loop filter is essential, but then where's the problem?
(leaving out important devices for now), it remains very simple diagram, suppose comparator, dt / logic stage and driver stage. all configurations in this company has many difficulties to enter good FB. (all amplifier would be perfect or the same performance).
Problem is in the stage pre-drive/drive architecture. all performances depends on it, crystal clear sound quality slew / rate etc..
B & O could not enter directly FB first stage of conversion because of the delay (total)
can not think of the sound driver as a step motor control.
example, suppose you change .. after comparator on Hypex, with traditional drive circuit you think it works the same? I remove entry-point of FB .. but back to the problem of other amp.🙂
vorrei provare un TC module, è possibile?
...Philips has had great intuition...🙂

I would try a TC module, is it possible?
Regards.
Sorry for my english
Click to expand...

I´m not shure that I get what you mean, but if you want to try out a TC module, you´should look here www.lcaudio.dk .
I think they are still open for single pcs orders.
 
#53
Just for clarification: A LC output filter does not add any delay to the signal above the resonant frequency, high frequencies are phase reversed but not delayed at all, so a simple RC phase lead network makes a single loop post-filter system unconditionally stable.
 
Status
Not open for further replies.
Top Bottom