AVI - Class D development

News over at AVI; They are working on a class D amplifier module. This may be used to power a sub though the potential is probably there for other applications. According to the designer, Martin, Class D amplification, as available elsewhere has inherent problems such as 'if one thing goes, the whole thing goes'. It would probably be worth pointing out that others, such as Primare to name only one, use Class D without many reported problems but I guess it can only be good if someone like AVI research and develop the technology and implement their own solution. - In the same article a new, smaller active 2 way is speculated on. It could potentially bring active AVI ownership down to a new lower level.

regards

I've liked Class D for quite a while now (and have made that clear on these forums), and I've yet to understand why those that promote 'accuracy' haven't embraced it. I've now used Class D amplification for my AV system for almost 4 years now and doubt I'll be going back to Class A/B.

Agreed.

I have an ES Sony TA-DA9000ES - Class D, but digital Class D, not analogue Class D, and more akin to an Lyngdorf or TacT Millenium in it's modus operandi than anything else.

I sold my Naim electronics after A/B'ing it to the Naim kit extensively, and would not swap it out for the likes of Krell, Audio Research, Mark Levinson, Gryphon or McIntosh which I've also comprehensively auditioned.  In fact, in the context of a passive separates system, I've not heard anything else that I've liked better, and am a big fan of the Rotel Class D units also.

If you want lots of headroom/power reserves and superb sound quality in a multi-channel amp without the drawbacks of component life shortening excessive heat eminating from a compact box, to say nothing of the need for A/C in hot climates, Class D is very much the way to go IMHO.

JMac

The new Pioneer A-50 is also a Class D amp.

Is that Class D as in "more complex, doesn’t perform as well and is more expensive"?

Still very happy with my Class D powered Marantz.

Something tells me that I've heard that one before,

JMac

I did copy and paste it...

As far as I see, Class D, as used elsewhere, usually offer relatively little dynamic headroom but almost double their power into lower loads. I am not so sure how this would sit with AVI's view of the importance of voltage swing and the dynamic potential of their more conventional power supplies. Perhaps, if these modules are powerful enough, 'headroom' is less important. That is if these will be used to power midwoofers/tweeters in the future, perhaps for the ADM's and perhaps a cheaper model. I guess that remains to be seen but they usually do things with purpose.

Regardless, it is good to see they dont rest on their laurels and continuously are evolving.

regards

From what I've heard, AVI were having some difficulty finding a class D design that fulfilled their requirements, so Martin is currently evaluating his own design.

Here is the rest of the info in a message from Ashley,

I'm being quoted on a other forum, so had better explain again precisely what we're doing.

As I previously said, Class D has higher distortion than good AB, which means, as JB discovered, it sounds better than Naim and as we know, it's not quite as good as our AB.

However Class D distortion at lower frequencies is good enough and for very high power applications, it is less expensive, so we're experimenting with a 500 Watt module for a possible new and better Sub.

The other application we're considering for our Class D amp is a very compact 5" Two way, where it would cost more than AB, but save space and avoid the need for cooling fins. It would only be used on the Bass driver and only then if it sounds okay up to 2-3kHz.

As I've previously explained, Class D is more expensive, more complex and so more likely to fail. Therefore we're thoroughly investigating every aspect of this by testing ours to destruction in a number of different ways. This will show us how to make it as reliable as our present range. So many PCBs were trashed over Xmas that we're waiting for more!

It may well be that we still decide not use Class D, but only by designing our own and not making all the mistakes DIY forum members do will we know.  - Ashley James, AVI.

JC

I wish whfsv would review a Wyred4sound class d product. 500 wpc must be worth a review, surely?

My old Lyngdorf SDAI2175 was bulletprroof. Ran cold. 200 WPC into 8 ohms, almost double into 4 and drove my Dali Ikon 6s until they would burst. Sold on now, but it was a lovely piece of kit. I'd say class D was the way to go.

Although I did have a bit of a smelly, burny moment when I wired in my old sub through the High level without reading the small print.

I don't think I've ever heard a class D amp, unless my Yamaha receiver had them.

Do class D amps consume less power than more traditional designs?

Have to confess I always have one eye on the leccy meter.

Yes.