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ClassDAudio Amps - Intro

wushuliu

Super Member
Begin of shpiel: I haven't perused AK in a while (frequented the TT forum, but my setup has been down for a while), so I thought I'd check in to see what people have thought of the ClassDAudio.com amps that are a big hit on AC and have been mentioned on other forums. So I did a search and man almost zilch! So I thought I'd at least get this info out to you guys! Since this is a more 'tinker' friendly forum I think it'll be a perfect fit.:thmbsp:


The Classdaudio amps are International Rectifier-based Class D Amps. As I go through forums I still read a lot of lingering doubts and old opinions of Class D/T amps that people still have, like they're bright or slightly unnatural or missing something, just good for subs, etc. Mostly opinions from years ago that just gets passed on. In the past few years ClassD/T amps like the Virtue Audio and Red Wine audio amps for instance have shown that the quality of sound is now firmly high-end and there are a lot of varieties that are still unknown to many people, except the hardcore diy crowd (I first heard about these on diyaudio and no other forum had even heard of them yet).

With the classdaudio kits you can build your amp. All the components are assembled already so literally all you need to do is connect them with wire and figure out how you want set up your switches/enclosure/rcas. And the sound quality is outstanding. Not mid-fi. Straight high-end. You can check out the Cheap and Cheerful forum at AC. People have sold their $multiple-k setups and replaced them with these and they have been compared to similar value gear over and over.

There are 120Wx2, 250WX2 in 4 and 8 ohm and more, and they are bridgeable.

Hate to sound like a commercial, but since there's almost no info here about these amps I'm trying to provide info to introduce to folks. Maybe some people who are familar can chime in so I don't seem like a shill. I'm just a big believer in cross-pollinization of info.

This kits are extremely easy and would make a great beginner project (just be careful, of course). Also Tom at CDA is super nice and accessible.

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Pic of my 250Wx2 (4 ohm). I'll add more later. Here endeth shpiel.
 

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I'd love to hear one.

Seems like a simple and relatively cheap way to build yourself an amp.
 
I contacted them about getting a bare board with no luck for the TI based amps. I have some ICs already from TI I just need to get around to laying out the boards and what not.

By the looks of it the boards that he uses are just the reference TI layout. I cant wait to hear one my self but ill have to do the boards my self.
 
I'd like to hear one of these myself. What is the rail +- voltage for the 250 wpc version?
 
40 to 50 V DC. It helps to check the web page! I have a mosfet kit amp that needs some work, it's running 45 volt rails with a shared 600va torroid trans & 2 22000 uF filter caps. I could strip out the heatsinks & amp boards & drop a 254 right in there. I have an old pro amp that delivers 250 wpc at 4 ohms, but it sure isn't 90% efficient!
 
You have read my mind !!! Just today I was wondering about some budget DIY amp, just looking for some info.. What about the chassis? Hoy to mount and really build one of this?
 
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You have read my mind !!! Just today I was wondering about some budget DIY amp, just looking for some info.. What about the chassis? Hoy to mount and really build one of this?

I've used a basic wooden enclosure and now have a Par-Metal Gold Alodine 20 series 12*12*4 enclosure. About $70 w/ shipping.

The kits come with standoffs to mount.
 
40-50V rails sound low to me for 250W amp??

No, I believe that is accurate. The IR chips takes an absolute max of +/-60v I believe. The International Rectifier pdf lists +/- 45 to 60v for 250wX2. My 250w kit was shipped with an Antek 32v 300VA toroid. If I understand correctly the rectifier in the PS = tranny voltage x 1.4. So 32v would come to 45v at the amp. If you have specific questions about the PS email Tom at classdaudio as he is very responsive.
 
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I just got my first taste of Class D/T amps, and so far, I'm really impressed!
Next step, will probably to find an inexpensive DIY kit, and substitute upgraded components..........................................

Steve
 
I dig this stuff... Ran the Dayton $20 t-amp for a few months while I built tube amps and was not disappointed.

I did change out the input caps and install a power switch.

Very impressive, really would be the route I'd recommend for my friends that want good audio on the cheap. Some nice vintage speakers and a $100 "t-amp" could be a rockin' budget system.
 
The first official, or unofficial, Class D amp was the SWAMP sold by Infinity. It was, as many of the products of the day, unreliable with unusual loads. Unusual loads were the order of the day in High-End Audio then.

I recently heard a T-Amp in my home and I have great hope for the genre.
 
I've used a basic wooden enclosure and now have a Par-Metal Gold Alodine 20 series 12*12*4 enclosure. About $70 w/ shipping.

The kits come with standoffs to mount.

Just this? Do you need to drill something? I 'm sure I can get something like this here in Buenos Aires. I should also get the transformer here, since I think it' s a bit heavy for mail shipping (I don' t know if the transformer that comes with the Kit is a very hi-quality one, It's difficult to get quality electronics components down here.)
 
Fact is, today, there are many low cost high performance amp options around. By the time you buy the PS, casing, etc.; the kit amps above are at around the same price as some very good pro options. The Behringer EP2500 is such an example; perfectly suited to any high performance speaker setup - only mod it needs is fan swap for an ultra-low noise fan and otherwise, you have an entirely finished amp with ability to drive just about any speaker load and produce up to 1100 watt x 2 into 2 Ohms, and despite the price, it is of very good build quality and design. This is a just a general summation, and I don't mean to suggest any particular brand or model.

-Chris
 
The first official, or unofficial, Class D amp was the SWAMP sold by Infinity. It was, as many of the products of the day, unreliable with unusual loads. Unusual loads were the order of the day in High-End Audio then.

I recently heard a T-Amp in my home and I have great hope for the genre.

Yes, T-amps are neat however things have come a long way since the 2024 sonic impact craze thanks to the DIY crowd.
 
Just this? Do you need to drill something? I 'm sure I can get something like this here in Buenos Aires. I should also get the transformer here, since I think it' s a bit heavy for mail shipping (I don' t know if the transformer that comes with the Kit is a very hi-quality one, It's difficult to get quality electronics components down here.)

? Drill? Maybe. How you build the enclosure is up to you. He does sell enclosure as well. Check the website. The transformers are high quality antek.
 
? Drill? Maybe. How you build the enclosure is up to you. He does sell enclosure as well. Check the website. The transformers are high quality antek.
I mean make holes for some power button, lights or leds, connectors... I'll check the enclosures offered in the website, I think they will match better....
 
I've been looking at these off and on for a while now. I've been looking for something to replace my Adcom GFA-545. As someone else said in the AudioCircle thread, I'm having a hard time finding a review comparing one to something I'm familiar with. For example, I've been looking at the Odyssey Stratos and McCormack DNA .5 and would love to hear how something from Class D Audio compares.
 
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