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Class D Switching Power Amplifiers and Power D/A conversion

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Old 22nd May 2009, 03:01 AM   #131
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Trying ultra low ESR paper. It good for all class d amp. Having to use high voltage kind, fold thrice. Also to can do ENABle PCB. This control to piezo cap. More can do copy tweak for Aussie Amp. Who steel half cookies? Can to wrap pizeo cap with ultra low and ENAble! Only silver, maybe black gate!! First Watt true, next comming to.

I nowing english some short only, no trnaslate. That gang racist for not agree with gullible club, bad logic. Moderator can do, no even telling what on topic. How many having to ask it for?
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Old 22nd May 2009, 04:58 AM   #132
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Old 22nd May 2009, 03:11 PM   #133
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Quote:
Originally posted by jkeny
Thanks for the report of the stages - it is even more informative & maybe Mike is listening in & could respond.

I came across these caps recently which seem to be stellar performers based on their specs & could have a role here http://www.paktron.com/pdf/Angstor_RA.pdf

They are Ultra-Low ESR Multilayer metallised polymer film capacitors. Capacitance values range from 0.1 F to 20 F and the voltage ratings are 50 VDC to 500 VDC.

This UK co is a distributor http://www.futureelectronics.com/en/...ges/index.aspx
John, hope your back is better. Brief reply will do a more detailed reply in the near future with plots of our amps compared to hypex should make interesting reading.

Nice to see James is making progress. We take on board the comments about caps and are aware of the more exotic low ESR caps but they are not used in our market place as standard.

We do have a new range of amplifiers coming out with more controls on for the pro audio market.

If there was enough interest we could produce a really high quality hi fi amplifier with dual current sources, dual current mirrors, dual differential input and low ESR caps throughout. This would comfortably give a THD+N of better than 0.005%. Please take note of the +N part which you will find others conveniently ignore.
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Old 22nd May 2009, 03:48 PM   #134
jkeny is offline jkeny  Ireland
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Hi Mike,
Thanks for asking - back was fine for a while & on Wed I decided to fix a laptop which needed a solder on it's PS input socket - result: laptop works, back doesn't. irony is the money I saved on new laptop, I will probably spend on physio!

Anyway, I understand your sentiments about esoteric low ESR caps in your products - my advice was more for Sharpi31
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Old 23rd May 2009, 08:37 PM   #135
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I appear to be Not Charles since someone else got there before me. :-)

Quote:
Originally posted by jkeny
Thanks for the report of the stages - it is even more informative & maybe Mike is listening in & could respond.

I came across these caps recently which seem to be stellar performers based on their specs & could have a role here http://www.paktron.com/pdf/Angstor_RA.pdf

They are Ultra-Low ESR Multilayer metallised polymer film capacitors. Capacitance values range from 0.1 F to 20 F and the voltage ratings are 50 VDC to 500 VDC.

This UK co is a distributor http://www.futureelectronics.com/en/...ges/index.aspx
I've been looking for something, second source, similar. Google seems to work. The American side of the pond were, sort of, wound component biased.

These capacitors look like the old Siemens devices which got sold off to Epcos. Just a moment.

http://www.epcos.com/web/generator/W...locale=en.html

Chances are that link won't work

Home page is http://www.epcos.com/

http://www.epcos.com/inf/20/20/db/fc..._B32560_64.pdf

are the 'unboxed' ones similar, maybe, to your equivalents.

One thing I have always liked about Siemens, and then Epcos, is the amount of data that they publish for their components. You might notice a slight difference between the Merkin data and the Epcos data.

Sigh. It means I have to go and qualify sources. Not that I wouldn't anyway but it would be nice if the data was available up front as a confidence builder.

I've got to say that as someone who is used to compensating 'analogue' systems I might feel the need to express some concern about what looks like arbitrary substitution of components in a delivered system.

I'd assume the manufacturer has design the product appropriately so messing about with things might end up breaking something. Reading about then perhaps playing with input capacitors or similar components won't hurt but when it comes to feedback components I'd be extremely wary about playing with them.

Low ESR might 'sound good' but, as a process control engineer, I've earned a bit of money replacing the bits someone bought off the back end of a lorry that were supposedly better/cheaper with the bits they should have used in the first place. The difference was something that did not work, lost production and some fruity repair bills versus something that did work.

They only ask once... Next time they ask first. :-)

Anyway, I am sort of surprised that you consider these components to be 'esoteric' I very much doubt that they are any different to the Epcos devices.

Thanks for the link though. I'll go and grill them. In the mean time it could be important so play safe.

Charles AKA NotCharles
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Old 8th July 2009, 07:12 AM   #136
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I've been using both the NX200 and UCD180HG power amps for a while now. I had been using a grounded grid preamp, then built a buffered passive using a cheap fet buffer board from ebay. With both preamps I liked both amps - the hypex was a bit better but there was very little in it.

Last week I finished building a modern twist on John Curl's JC-2 preamp. The board is available on ebay, and I have no idea how close the schematic is to a proper JC-2 or how it compares one. I first connected it to the NX200 amp and found the sound very detailed but a bit bright and brash (especially in comparison with the fet buffered pre I'd been using most recently). I changed power amps and found a far greater degree of difference than I had noticed previously. The hypex was so much smoother and warmer - for the first time I'm not tempted to swap amps back and forward.

It may well be that my dodgy JC-2 is far happier with the 100K input impedance of the hypex, and that the sound suffers when connected to the 12K input of the NX200. Whatever the reason, there is no doubt that the hypex is preferrable to me in this system.
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Old 25th August 2009, 02:15 PM   #137
kp93300 is offline kp93300  Malaysia
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Default Upgraded version of NX 200

HI Mike,
Have you designed the upgraded version as stated in your last post ?
Besides more power, any sound difference between NX 200 and NX 400?
Thanks
kp93300
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