Q: Overview of CLASS D amps out there?? - diyAudio
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Old 22nd October 2004, 04:06 PM   #1
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Default Q: Overview of CLASS D amps out there??

Ok,

here's my question:

How about an overview of the various DIY class D units that are currently out there, especially those with kit/partial kit/pcb availability, prices, *and* a brief on their pros and cons??

I realize that if you've been reading the Class D area for a while you've probably got a good grasp of this, but heck, I'd like to come up to speed on this without having to review a few hundred posts...

Maybe this might make a good sticky??

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_-_-bear
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Old 22nd October 2004, 04:44 PM   #2
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I wonder, are there any DIY class D projects which are worth mentioning, I mean which produce decent fidelity?
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Old 22nd October 2004, 06:59 PM   #3
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I've been looking around recently and have not actually located any class D projects with PCB's and such. The only things I've seen are evaluation boards from fairly large companies... and the cheapest ones there are $99 from Tripath. Others are $199 and up. I would be very interested in having a list of DIY projects aas well... I am interested in building, but cannot locate anything that is cheap enough to warrant me "experimenting" with. If I kill a $200 amp, I will be somewhat upset.
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Old 24th October 2004, 12:38 AM   #4
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Elektor has published a very interesting amp based on the Tripath TA 3020. Issues June, september and october this year. A PCB is 49 euro and all SMD parts are already soldered on. Also includes metal cores for the coils.
Cheaper and probably better (due to the SMD parts) than the evaluation boards from Tripath.

But I don't think I will order these boards myself. Still working on an Aleph-X. When the Aleph is finished I will probably go for the UCD modules. According to some posters here they are manna from heaven. And Hypex which sells the UCD modules is only half an hour drive from here........
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Old 31st October 2004, 07:22 PM   #5
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Default Online info on Elektor class-D amp?

Hi dr.strangelove3 (and others)

Apart from that one 'teaser' picture of the elektor amp included in your post - is there any other 'on line' info on this construction out there i cyberspace ???
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Old 1st November 2004, 05:31 AM   #6
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Go to

http://www.classd.org/indexold.html

and have a look under OEM products.

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Charles
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Old 5th November 2004, 04:10 PM   #7
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Default classd.org

Their reviews are old. For example the ICE Power review. They state the ICE power modules use the LM324. Other than a few prototypes, they have never shipped modules with the LM324. They currently use the MC33078 and MC33079 devices which are quite good.

I know the designer of these modules personally (and have reverse engineered them) and the design is very good. I have used thousands of their modules and have had rave reviews from our customers. And only one field failure.

While they don't measure quite as good as the finest linear amplifiers, their distortion characteristics are closer to a tube amplifier than a traditional class AB amplifier.
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Old 7th November 2004, 10:01 AM   #8
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Default D2Audio

Hi,
Any info or comments on D2Audio. They offer some really interesting features like built in cross-overs. But my feeling is that this is consumer level gear. Am I right? Or do they perform up to ICE or UCD?
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Old 8th November 2004, 04:42 PM   #9
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Default D2Audio

I am very familiar with D2audio products. only a month ago I had dinner with founder of the company and am in almost daily correspondence with several of their engineering staff. I have been to their headquartrs in Austin TX, have received pre-production prototypes of several products and had further meetings with the management at the AES show in San Francisco barely more than a week ago.

And I have the evaluation kit for the 4 channel unit in my office and have 24 of the 8 channel modules in stock with 220 more on order.

So yes, I'd say I am familiar. We are using their XS100, 8 channel module as the basis of a steerable column speaker. This is where by using the DSPs in 2 eight channel modules, we can take an array of 16 speakers and electrically steer the vertical dispersion pattern. and we're doing it in a way that unlike the competition who merely use stepped time delays, with patented technology from Europe, that there will be essentially no uncontrolled side lobes in the horizontal plane.

Their early modules did not meet, in my opinion, modern consumer audio specifications, let alone pro specs. However, now that they have their own silicon, they re now well above the threshold for consumer audio, are just at professional level but are not quite at audiophile grade. However, the DSP in the modules is really nice and really easy to use. We don't use their GUI and have a completely different one in the ones we get but their standard setup is really useful and easy to use.

They ship piles of the 4 channel modules to Harmon International every month. I have no idea if their products are available on the small user market. See their web site at www.d2audio.com.

Overall, I would say that if you can get their current production modules, I would say that they are an interesting thing to look at.

And how do they sound? I would say that compared to the ICE Power modules, they are reasonably similar though there may be a little more low level granularity in the D2Audio because they are pure digital while the ICE Power are analog PWM. Also, set the limiters so they can't clip. The clipping is a lot harsher than in the ICE Power. This is because the ICE Power people have deliberately put a soft clipping feature in their products while the D2Audio clips just as bad as a Class AB amplifier.

The bad part - D2Audio products have no power supply rejection ratio and must be used with a regulated power supply. We are getting a 320W 48V power supply from a company called Skynet for about $85.00 each that seem to work just fine.
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Old 11th November 2004, 02:40 PM   #10
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hi.

if you want to make your own survey may i suggest you take a look at: www.cadaudio.dk

rgds - karsten madsen - cadaudio.dk
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