UCD180 questions

[JohnW]

Bruno,

My mistake – your right, I was thinking about the Gate Oxide – fading memory (combined with the hair loss)..

Its not surprising that reducing the Epi layer reduces the Avalanche ratings….

John

[peranders]

Originally posted by classd4sure



Welcome to the dark side Peranders, you'll never go back.
Originally it was "Ultimate Class D" and now it's "Universal.." but..
it's pretty much the ultimate today anyway. Have you seen a simpler amplifier, witch such good specifications, and such good sound?

You're right it's just a half bridge, the usual advantages can be had by going with a full bridge. Power supply pumping immunity, less noise, more power.

Thanks for your endorsement for the class d forum, best to stick us in our own little corner before we take over

I think class D is where digital photo is today. Give class D a couple of more years and we will have something which can meet real high-end.

I think class D is exciting but also difficult. I'm thinking of RFI/EMI mostly and what this affects equiptment.

[classd4sure]

Originally posted by peranders

I think class D is where digital photo is today. Give class D a couple of more years and we will have something which can meet real high-end.

I think class D is exciting but also difficult. I'm thinking of RFI/EMI mostly and what this affects equiptment.

OK, out with you!!

I think it not only meets real hi-fi now but defines it.
Really every class of amp isn't without its difficulties..

See, I can tell you've looked into it very little, (not at all) and those are rather strong statements to make considering that.

With a balanced filter and proper design techniques, RFI/EMI... won't be very different that of your cell phone, monitor, pc power supply... etc.

Give it a chance you might change your mind, is what I'm saying.

[phase_accurate]

I think there are two facts that delayed the evolution of class-d amps:

1. ) Availability of suitable components, this problem can be regarded as solved.

2.) Engineers who work in the switchmode-area are usually not audio enginners. And much worse most audio engineers lack the lateral thinking needed for the development of class-d amps. But this one is solved also nowadays.

BTW: The oldest patent proposing a really cool class-d topology (with the inclusion of the output filter into the NFB loop) is from the late seventies. At least two professional products are available that use this topology.

Regards

Charles

[ewildgoose]

The first PWM amplifier kit on the market (that I am aware of) was from ....



.... wait for it ...


... Clive Sinclair ....!


What a guy! Someone showed me an original advert for one the other day

[Jan-Peter]

Hi Guys,

I have been a way for a few days , sorry for the late reply!

Roland (Paradigm),

Nice to hear about your experience!

Many thanks for your congratulation. We are manufacturing for almost 10 year audio power amplifers (besides my 15 years of personal hobby experience), and during this time I have seen a lot of Class-D amplifiers. When I test an amp on the workbench I always first put a dummy load on the amp and a sinewave generator together with an oscilloscope. To see how much power we can get out of this amp and if everything looks ok. By testing the Class-D amplifiers I was always very disappointed with the outputsignal of this kind of amps, a lot of HF-switching noise and an awful clipping behavour.

Till I get the opportunity for a demonstrating by the Philips Labs in Belgium of the Universal Class D amplifier. On that moment I saw for the fist time a Class-D amplifier with a very clean outputsignal, who runs in clipping very nice, and showed a very good 10KHz rectangular wave at the output.

After a listening test and a comparing with our own analog amplifier I was convinced and decided to use this technique!

Roland, can you show us your pictures on this forum? I am quit curious....

Peranders,

Yes, indeed we use an half-bridge output. The advantage in comparison with a full bridge is;
- only one outputcoil.
- a real grounded output. Not a positive and negative outputsignal.
- less EMC output.
- no need for an extra powervoltage.

Class-D is were digital photos are at the moment? Interesting comparation
I guess for this discussion it will be the best Bruno could jump in.
I am not such an expert in true High End Amplifiers

Regards,

Jan-Peter

www.hypex.nl

[classd4sure]

Originally posted by Jan-Peter
Hi Guys,

I have been a way for a few days , sorry for the late reply!

Roland (Paradigm),

Nice to hear about your experience!

Many thanks for your congratulation. We are manufacturing for almost 10 year audio power amplifers (besides my 15 years of personal hobby experience), and during this time I have seen a lot of Class-D amplifiers. When I test an amp on the workbench I always first put a dummy load on the amp and a sinewave generator together with an oscilloscope. To see how much power we can get out of this amp and if everything looks ok. By testing the Class-D amplifiers I was always very disappointed with the outputsignal of this kind of amps, a lot of HF-switching noise and an awful clipping behavour.

Till I get the opportunity for a demonstrating by the Philips Labs in Belgium of the Universal Class D amplifier. On that moment I saw for the fist time a Class-D amplifier with a very clean outputsignal, who runs in clipping very nice, and showed a very good 10KHz rectangular wave at the output.

After a listening test and a comparing with our own analog amplifier I was convinced and decided to use this technique!

Roland, can you how us your pictures on this forum? I am quit curious....

Peranders,

Yes, indeed we use an half-bridge output. The advantage in comparison with a full bridge is;
- only one outputcoil.
- a real grounded output. Not a positive and negative outputsignal.
- less EMC output.
- no need for an extra powervoltage.

Class-D is were digital photos are at the moment? Interesting comparation
I guess for this discussion it will be the best Bruno could jump in.
I am not such an expert in true High End Amplifiers

Regards,

Jan-Peter

www.hypex.nl

Hi,

I would have thought the main advantage to a half bridge is reduced cost, but it suffers in other areas with respect to a full bridge. I was also under the impression that a full bridge has less EMI.

I'm not sure what you meant by no extra power voltage, you don't operate it from one rail do you? If so, don't you sacrifice your real grounded load. Maybe I misunderstood?

All that aside, which one should sound better?

[peranders]

Originally posted by Jan-Peter
Class-D is were digital photos are at the moment? Interesting comparation
I guess for this discussion it will be the best Bruno could jump in.
I am not such an expert in true High End Amplifiers

What I ment is that it's a real alternative now. 4 Mpx with very good optics are OK for many applications.... but not all. Not even 10-14 Mpx isn't the same as film. The very main thing is the power consumption of the camera

So what I mean is that Class D has potential not only for bass or low-fi or mid-fi.

I wish you good luck with you modules, they sure look nice. Can't you supply as with more detailed photo?

[peranders]

Originally posted by Jan-Peter

Yes, indeed we use an half-bridge output. The advantage in comparison with a full bridge is;
- only one outputcoil.
- a real grounded output. Not a positive and negative outputsignal.
- less EMC output.
- no need for an extra powervoltage.

What about using four transistors which are the same compared to one P-channel and one N-channel which never (by nature) can be alike?

[phase_accurate]

What about using four transistors which are the same compared to one P-channel and one N-channel which never (by nature) can be alike?

Most class-d designs use only N-channel MOSFETS nowadays due to better specs.

Another advantage of single ended amps: They can be bridged far more easily than full bridges !


Regards

Charles