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Class D Switching Power Amplifiers and Power D/A conversion

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Old 1st January 2009, 09:03 AM   #1
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Default I could really use some feedback!

I plan on building Hypex 400 monoblocks in a single chassis with one IEC inlet.

I want to use either a Hypex 500va transformer on each channel or a Hypex 250va on each channel.

Which transformer would you recommend?

Can I use a - SINGLE - Softstart module to control both transformers (assuming I use the 500va transformers)?

Thank you in advance.
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Old 2nd January 2009, 11:30 PM   #2
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Default UcD 400 power supply

I've actually had really good luck with the Coldamp 800w SMPS powering my UcD 400 implementations. Simpler to wire, less weight, and no need for the soft-start at all. Fabulous sound too!

Regards,
Tom
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Old 3rd January 2009, 05:25 AM   #3
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Default Re: UcD 400 power supply

"Luck", indeed..


Slowlearner, two 250VA is enough but you'd likely be happier with either one or two of the 500VA for practical reasons, where you then benefit from soft start, and one of them can switch two transformers as you can see for yourself in the datasheet.
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Old 3rd January 2009, 01:39 PM   #4
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Default Linear vs Switching supply...

classdphile,

I am curious. Have other folks had bad "luck" with the Coldamp supply?

I've abused mine pretty well and it works fine. I have insulated the heck out of it and have been careful about the clearances (all SMPS scare me) but so far it has been an immaculate solution.

I've built a few UcD400 and UcD180 boxes (some traffo'd and some SMPS'd) and I don't notice any sonic difference but the amps weigh 80% less and are far easier to build based on the SMPS.

I'd be interested why you are not a fan.

Regards,
Tom
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Old 3rd January 2009, 11:11 PM   #5
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It seems negotiating with hijackers isn't an option here, any such post will mysteriously be deleted.

At least your questions were previously answered in the actual discussion on the matter, that you took part in.

I'd still like to know, if you hear no sonic differences between the two types of supply, can you say it works as advertised:

http://www.diyaudio.com/forums/showt...10#post1106210
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Old 4th January 2009, 12:46 PM   #6
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Default a thousand apologies...

I am sorry.

I didn't have any intention of hijacking this thread - I felt the info I offered slowlearner was relevant.

My side-track to you was undisciplined but not an intentional hijack.

To his question, directly, If he wants to go linear that I found (as classdphile points out in my previous post) that a single 1kva traffo was most efficient build-wise and seemed to have plenty of headroom for both UcD400's to run flat-out. I think that the gains realized by a *complete* dual-mono implementation aren't worth the additional hardware, wiring, and weight.

Once again I apologize for the misunderstanding.

[edit]
classdphile - to your question.
The SPS80 has performed to spec and as advertised. It doesn't add any magic sonics - in fact - I can't hear any difference between the linear supply and the SMPS implementations of the UcD400. It has been reliable for about a year of pretty hard use.
[/edit]

Regards,
Tom
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Old 4th January 2009, 08:03 PM   #7
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Default Re: I could really use some feedback!

Quote:
Originally posted by slowlearner
I plan on building Hypex 400 monoblocks in a single chassis with one IEC inlet.
I'm doing the same right now. Just trying to find time to get it all into the chassis now.

I used two 500VA transformers. 250VA is technically enough for real world use, music, etc... but I'm a fan of overkill ;-)
(the larger supply should in theory allow for a little better load regulation by the transformer, a bit stiffer supply, may or may not make much audible difference to the end result...)

Also, I didn't by Hypex transformers. I'm sure they're good, but didn't feel like paying to ship them here. I did buy their soft start since it has some nice features. And Yes, it will work for two transformers, or any number really, as long as your total is below 1500VA (Hypex spec for the softstart - somewhere in their docs)

good luck & have fun!

-Chris
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Old 4th January 2009, 11:44 PM   #8
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eclectic2k,

Could you please tell me where you purchased your transfomers and which specific ones you purchased.

And to the others who responded here. Thank you for your replies. I would like to use a SMPS for the UCD 400s, but a Hypex SMPS for the 400s is not available yet. I read that a SMPS for the 400s was supposed to be available at any time, but nothing yet.

The Coldamp SMPS sounds interesting, but I don't have the same confidence in Coldamp that I do in Hypex.
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Old 5th January 2009, 04:45 AM   #9
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Default Re: a thousand apologies...

Hi Tom,

In view of the link your declaration doesn't seem to measure up somehow.

Really though, you should hear a difference in your prototypes, just as you should with dual mono. Must be more to it than size, weight, and ease of plugging it all together.
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Old 5th January 2009, 03:40 PM   #10
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Default hi berns

hi berns,

I do hear a difference in both dual-mono and the SMPS implementations as opposed to a single linear power supply - it's just that those differences aren't *magic* or game-changing. Furthermore ones choice of loudspeakers makes a huge difference.

BTW - My old link you posted had but a single reply that didn't answer my question so I didn't flog it further.

After having built a few of these amps I agree that there is more to it than plug-n-play, <grin>, however, when you're building a pile of them the ease of assembly makes a big difference...

Regards,
Tom
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