TC Electronics Switch amp

[AP2]

To Kurt von Kubik:
Hi,
OK, I know ICEpower, has a good sound.
interesting is the second FB, because t is not easy to implement, depends on the architecture of the amplifier (it must necessarily have a very low delay from input to output) so this is already good.
probably have added a filter on ring of FB to stabilize response at low frequencies(HI-damping is necessary on this zone).

[Eva]

Originally Posted by Kurt von Kubik

Whether the modules can handle the power specified or not, I do not know, since I did not measure it, but I have no reason to doubt it what so ever. They are indeed very strong.

About the multiple feedback loops vs. only one, then this is THE item in class D amplification.
A feedbackloop around the LPF filter in the output will always be slow, and therefor be audio frequencies only. This given the output impedance will rise with frequency, typical the amping factor ends up around 1-10 @ 20KHz or even worse.
In addition stability is poor.
ICE Power with its extra loop, is both very stable and also has a smoother decrease in dampingfactor than alternatives.
The TC module though has an outputimpedance @ 1KHz measuring a few µ Ohms, giving it several millions in dampingfactor, of which tens of thousand are still available @ higher frequencies.

There are many myths around class D feedback schemes that are not necessarily true. Taking the feedback after the output filter does not always result in high output
impedance at high frequencies or instability.

I get around 0.075 ohm output impedance at 10khz with a "single" feedback loop, and this is in the version of my amplifier intended for low frequencies, whose output filter resonates at 12khz and which switches at 125khz, but the feedback loop eliminates any trace of filter resonance. Also, my feedback scheme allows to get -1dB around 15khz, thus extending the usable frequency response of the amplifier well above filter resonance.

UcD exhibits similar performance, but they don't go to the point of extending frequency response past filter resonance. ICEpower suffers from high output impedance at high frequencies. The full range version of my amplifier has everything moved up in the frequency domain by approx. a 2x factor at the expense of some efficiency loss. The low frequency version can also play music quite loud on 4 ohm withou any heatsinking other than the copper tab of the TO-220 transistors, over 100V peak. We are probably using the same latest generation IR or Fairchild MOSFET. This is probably going to become standard performance level within a few years.

[AP2]

to EVA:

Hi,
this is class D module (not public),developed in 2003
300w rms,400 Khz triangle wave, includes:
clip led,alc,pb adj,mute,regulate +/-15 on board,all protections.
continuos power without externalparts.
20Hz-40Khz bw -1 dB

very hi-Resolution. sound vey similar at class A-B
at 400khz, all is very complicate...

[Ltralus]

Originally Posted by Eva

The two feedback loops on ICEpower are redundant. The same result may be achieved with a single post-filter loop and an output filter and layout having low parasitics. That's UcD, although it may be considered as having two loops because the signal taken from the output follows two different paths. In general, I think that a "single" feedback loop (like that) can do it all, but it may include several poles.

The 60A peak current capabilty may easily be real, although that's not very reliable for one pair of MOSFET with such a small heatsink, unless there is time/temperature dependent current limiting. But then the modules should also be rated at 2 ohm, and they aren't. Also, output coils don't look like capable of handling more than 10A rms or so for some time.

For example, my current project can do around 5kw on 2 ohm for 1 second (with time-dependent true-RMS current limiting to protect not only the amplifier but the power source and the load ). Current limit is 75A peak and 25A rms long term, but that's achieved using pairs of parallel MOSFET, and 13 AWG wire on output coils. There are low cost tricks to calculate rms current without expensive multiplier ICs.

It is not UCD eva, and it wouldn't be the same result at all as their performance is not equivalent. Perhaps you should reread the threads where their differences have already been discussed. Why must all your posts turn into a product advertisement for yourself?

[Ltralus]

Originally Posted by Eva

There are many myths around class D feedback schemes that are not necessarily true. Taking the feedback after the output filter does not always result in high output
impedance at high frequencies or instability.

I get around 0.075 ohm output impedance at 10khz with a "single" feedback loop, and this is in the version of my amplifier intended for low frequencies, whose output filter resonates at 12khz and which switches at 125khz, but the feedback loop eliminates any trace of filter resonance. Also, my feedback scheme allows to get -1dB around 15khz, thus extending the usable frequency response of the amplifier well above filter resonance.

UcD exhibits similar performance, but they don't go to the point of extending frequency response past filter resonance. ICEpower suffers from high output impedance at high frequencies. The full range version of my amplifier has everything moved up in the frequency domain by approx. a 2x factor at the expense of some efficiency loss. The low frequency version can also play music quite loud on 4 ohm withou any heatsinking other than the copper tab of the TO-220 transistors, over 100V peak. We are probably using the same latest generation IR or Fairchild MOSFET. This is probably going to become standard performance level within a few years.

Have you not seen the datasheet? Of course UCD has small signal response beyond filter cut off, where do you think you got the trick? Just another advertisement.

[Workhorse]

Originally Posted by Kurt von Kubik

Yes it is the current LC module, but it is not designed by Lars Clausen.

Doest it means, it will have lesser catastrophic modes also

BTW:do you guys have good customer support like brenda offers?

[Workhorse]

Originally Posted by Eva

Taking the feedback after the output filter does not always result in high output
impedance at high frequencies or instability.

Taking feedback AFTER the filter[post filter], always reduces OUTPUT IMPEDANCE in comparision with pre-filter feedback.

[Kurt von Kubik]

Well the Hypex modules uses a different technology than B&O.
You can read all about it @ their website, they actually produced an endless series of academic papers, presented at AES conventions through the last decade.
The designer of the TC module was part of the team behind amongst others this paper http://www.icepower.bang-olufsen.com...ntion/5197.pdf
This describes in detail some of the essentials in ICE power, which is not at all available anywhere else in any form besides TC.

Through time`I´ve had many visitors coming by showing me their class D amplifiers, and it has been a long row of funny experiences.
Four times did the amps commit suicide just in front of us, all of these burns were due to unloaded condition. This because we compared them to my linear amps, but when unloaded for a few minutes they died.
It was amps from Hypex, Nuforce and Tripath.
ICE power amps such as Acoustic Reality and Bertram were in the contrary unconditionally stable, and they could easily be switched on without load.

Today ICE has sold more than 100 mio channels, and more than 30 engineers are employed in optimizing the technology.
Looking at data and theory of operation of both ICE and Hypex, leaves no doubt on which technology is superior, and in my experience this also goes for the sonic impression.
Unfortunately ICE is not available to DIYérs, but luckily the TC module is. It is a bit pricy though, but compared to linear amps available on the market, you´ll have to spend loads of money to get comparable performance.

[Workhorse]

Originally Posted by Kurt von Kubik

Four times did the amps commit suicide just in front of us, all of these burns were due to unloaded condition. This because we compared them to my linear amps, but when unloaded for a few minutes they died.
It was amps from Hypex, Nuforce and Tripath.
ICE power amps such as Acoustic Reality and Bertram were in the contrary unconditionally stable, and they could easily be switched on without load.

UCD committs suicide when driven with NO LOAD??

Recently I saw a smoked ICE-Power amp in active speaker, the speaker coil wire was broken, probablya manufacturing defect, but it created the same open-load condition.

[Kurt von Kubik]

Originally Posted by Workhorse

Doest it means, it will have lesser catastrophic modes also

BTW:do you guys have good customer support like brenda offers?

The TC module is completely "LC less" which means it does not share any kind of technology with both ZAP pulse and New Class D.

What do you mean "costumer support"?
I´m not trying to sell any of those modules, they can be ordered at LC audio, but I do not have any interest in that business.

We are building our own support circuitry for it, later when they are closed, you can have schematics.

My interest in this is only, that I became quite impressed by the sound of it, and that was a first time ever for class D.