Fascinating interview with Class D inventor Bruno Putzeys

Thanks Bill but someone already beat you to the punch in correcting me.

 

I'm sure if this was the early 1960s when transistor based audio equipment was introduced the same could be said.

And imagine if we judged ALL transistor based audio equipment on the performance of what was then available which were a lot of pretty poor sounding audio equipment when compared against tube equipment. It took many years before a great sounding transistor amplifier was designed.

 

I agree with this entirely, room acoustics are a huge factor, just as they are in a live venue. After that its a case of a little luck with matching components that work in harmony. I am not saying that Class D or any other type of amp is more satisfying than any other. One of my favourite amps was the forerunner to Audionote gear ( Audio Innovations 2nd's ). In no way would it be close to Hypex based amps in any measurable parameter, but it sounded delicious with a valve pre amp and open baffle speakers of 98/w on most material. Was it accurate ? no way.

2nd harmonic distortion can add some lovely flavour and certainly make some borderline recordings sound more listenable than they might be with an accurate wire with gain amplifier. I suppose I'm getting round to the realisation that accurate replay is not everyones cup of tea. In an ideal work of great recordings where all is revealed in a fantastic approximation of the real thing tone manipulation would be not quite so desirable or satisfying.

 

Agreed. However, I think DSP's true frontier will be the intelligent optimisation of any speaker in any room, i.e with zero effort from the user. This will have far greater influence over sound than amp modelling.

 

Take a look at the Kii 3. Interesting..

 

Being from Brooklyn, I'm not even going to attempt pronouncing that last name.

To business - I have a CA Azur 851A integrated, which runs in their "proprietary" class XD, e.i. the first 10W are in class A, above that it switches to class D. It certainly isn't the last word in amplification, but sounds nice, and I honestly can't hear the switch from A to D.

However, when I see class D equipment priced in the stratosphere, like Jeff Rowland, for one - it makes me wonder...

 

And WAS said I'm sure! However, I think NP is saying that the basic operation of Class D does not lend itself to amplifying analog audio (say that 1o times fast!). So that's why it's a miracle than anyone can design a decent one.

On a different note, my dad STILL uses a Philips radio (AM/FM/SW, he likes to listen to overseas shortwave) which was the first transistor radio sold in South America. It is older than me! It is older than the moon landing! It sounds quite good, probably because the quality of the speaker is better than what you'd get today in a similar item.

 

Yes, I agree, although I think this will be a niche that will take a while to become mainstream, if ever. At least among "normal" speakers-a review of the Apple Homepod says it actually optimizes itself to the room as it plays music-maybe like an old rock concert sound trick which would do out/in FFTs of the music playing to determine the response of the system.

I was fortunate enough to attend a "Virtual Soundcheck" event before a Tom Petty concert at The Forum, and the EAW Anya system is DSP-tunable to the room. 9 years of software development. The system sounded really good throughout the venue-close seats, high seats, out front, to the side. It was really remarkable.

 

I would be scared to know what you guys think of my TEAC AI-301DA.

I got it on sale for $325 recently. I'm happy with it and I feel like it's a major improvement over the internal circuitry in my iMac. But, as you might guess..it's a Class D amp with a BurrBrown PCM 1795 D/A converter.

 

Yup. Like I said upthread, my Pioneer receiver has phase control for the sub, which makes it sound like a completely different, far tighter unit. People go on and on about the electronic crossover and the room EQ, and they're important to be sure, but I suspect the real audible advantage of sophisticated auto-correcting DSPs won't come from that, but from correcting for phase and timing issues. I suspect those are actually the biggest barriers to accurate reproduction in most setups. Wouldn't be surprised to see a DSP able to transform meh speakers into audiophile-grade performers by tweaking a slew of parameters.

 

I'd get one of those for that price if I could get one that cheap in Spain,but unfortunately won't be the case.

 

Touring is what most class-D amplifier's are used for, because they are lighter. They are also used extensively in fixed live sound PA applications, like in theaters, where they sound good.

I have an small 19" audio rack behind the TV, that has two Crown XTi-2000's in it. It is on wheels, in the event that I wanted to take the A7's out of the listening room.

They have a dynamic that works well in a live sound environment.

I have a pair of RTiA9's that I would drive with an Emotiva XPS-2 power amplifier. It is rated to deliver 250-Watts into an 8-Ohm load and 400-WPC into a 4-Ohm load. It also weighs 72-lbs. It seems happy sitting in the same spot that I placed it in when I first bought it (it is a generation one), so I remain content to leave it where it is.

It powered the A9's excellently well. Those large tower speakers can really put out some sound and could fill almost any room well. They, like the Polk LSiM707's that I'm currently running as mains, do like to have a lot of power. But then, thy both put out a lot of sound.

I do use one of the XTi-2000's to run a 15" horn loaded passive commercial sub. I have the Crown running in bridged mono mode, which can deliver 1,600 watts into 8-Ohms. The sub is a UCS1 and it can handle 1,200-Watts program material and operate at a sustained 133-dB.

You need a serious amplifier in order to create large amounts of sub-bass.

This is where class-D really shines. It will even drive 4-Ohm loads in bridged mono mode, which most amplifier's can not even come close to doing.

A year or so back, I did purchase a used Peachtree Decco65, which was when Peachtree first switched from A/B power amps to class-D. I was curious to find out how their new class-D stuff would sound and thought it might be nice have as a back-up amplifier.

As @Helom previously commented it dd have a sterile sound to it. But then I was running it on the Altec A7's, where SS amplification does have a sterile sound. For this reason, I have stopped using any SS amp on the horn driven A7's. With the Altec's, tubes are the only way to go.

Since Peachtree came out with their first class-D efforts, they have had two or three generations of integrated amplifier's to improve their class-D efforts, as well as having newer DAC's.

Class-D has probably progressed to the point that some of the units, that are now current models, would sound OK with average tower speakers. The kind that would be used for HT and stereo, that are voiced with SS amps, to begin with.

 

My Esoteric I-03 Class D Integrated weighs 68 pounds. Class D equipment can be heavy!

 

6moons Esoteric I-03