Class D Amps - will they be the future.

[Cereal Killer]

Have been thinking about Class D amplification. Why for all its qualities and eco friendliness has it not become the norm. Since were all moving closer and closer to a full on digital invasion is there any reason why we stick to analogue, is class D just not there yet or is it just a technology that doesn’t work as well. I’ve never owned or even heard a proper class D amp such as, tact, bel canto, lyngdorf etc. the American and Europeans seen to have taking the bate. Are there any British made units?

the best application is can think of is the German ADAMs top flight speaker cant remember what its called but it used 40 ice units in total and is supposed to be amongst the best active speakers in the world.. so is Class D not used because were so entwined in the industry, its production process and its current form that a wholesale change would effectively re-invent it? or is Class D just in its infant days and as of yet, needs to find its feet?

 

[shrink]

well... i have owned bel canto class D amps... and they are very good in many ways.. but not perfect. I dont think class D is all the way there yet. I find the treble a little dry and the bass a tad over dampened. My accuphase E-550 stuffs the 1000w class D monoblocks truly. It wasnt even close.

Class D might mature well, but its a long way off the best traditional solid state and valve solutions yet.

 

[Papa Lazarou]

well... i have owned bel canto class D amps... and they are very good in many ways.. but not perfect. I dont think class D is all the way there yet. I find the treble a little dry and the bass a tad over dampened. My accuphase E-550 stuffs the 1000w class D monoblocks truly. It wasnt even close.

Class D might mature well, but its a long way off the best traditional solid state and valve solutions yet.

My findings exactly, having also tried (well owned actually) the 1000w Class D monos (Bel Canto).
My Karan absolutely stuffed the Bel Canto pre-power at half the price, it wasn't even close!
I find that music usually sounds quite detached and soulless through Class D.

 

[muzzer]

I have heard a power amp built around the Hypex modules and mighty fine it was, I am saving for one at the moment. The one in question was built by Colin at Chevron Audio nr Derby.

 

[adam69]

is class D just not there yet or is it just a technology that doesn’t work as well.

IMHO it is there and if it doesn't work (sound) as good then again I don't think it's been designed well, I use class D 400W monos and the resolution is simply unbelievable, there is no way anyone can say class D hasn't come of age, they just need to hear the right class D amps

Sonneteer Bronte was a class D amp using a Tripath chip.

Class D has arrived.

 

[Jonboi]

Well, it depends really.

I think Class D will become more prevalent, and is a godsend for actives, as the technology can be small and give off very little heat, and compared to say a Class A SS amp, comparatively cheap to build.

There are also different implementations of so called class D, or switching amplifiers, or PWM (Pulse width modulating) amps as they're sometimes called.

Some, such as the B&O ICE power technology, are analogue in that they use an analogue input signal from which they create the waveform 'pulse' for amplification by switching the output transistors and thus controlling the power supply. Others, such as TacT Millienium, Lyngdorf, Sony S-Master Pro, and I believe some of the Matsushita (Panasonic) designs use a digital bitstream to create the waveform 'pulse'. Some (such as the ICE power) use global negative feedback, whereas others such as the Sony use no negative feedback at all, so there is Class D, and Class D.

I would expect the ICE power designs to have more bass grip and drive, whereas the TACT/Lyngdorf/S-Master Pro which are all very similar in design essence, to be softer in the bass, but have a greater sense of resolution and musical 'flow'. As to Class D not being quite 'there' I read my share of reviews on my amp when I got it, and read of owners on US forums of McIntosh and Krell, trading 'up' to the big digital Sony, so once again personal preference strongly comes into it i would suggest.

I've heard the latest ICE power Rotels, and to my mind they have the excitement/PRaT of olive Naim, with non of the shortfalls re edge, grain, glare etc. They have a very smooth, rich creamy sound, full of life; darkish tonality, a bit like the latest classic naim in that regard. I use naim as a sound reference here, only because I've owned the stuff, and many here still do, so can possibly relate to what I'm describing by way of comparison.

Of my experience with Naim and the big Sony; well I clearly prefer it to and rate it better than an NAP500 - again others will differ, but I dont' think it could be described as immature technology. Then again, whilst there are drawbacks to class D design, I'm pretty sure with the push to environmental considerations, and the attractiveness of small, low heat amplifier modules, that it will become mainstream in a big way before long, and that in turn will lead to technology likely overcoming the shortcomings of the design.

Personally, I love it... but hey,, that's just me... I've been learning to think outside the conventional 'Hi-End' hifi pen for a while now...lol

Best

Jon....

 

[muzzer]

r-tee.
The one I heard was in Colins own system so I cannot really compare it to anything apart from his previous amp which was a highly regarded DPA amp suffice to say it sounded very neutral,detailed, sort of somewhere between a valve and solid state in character but without the compromises of these types.
The ones on the Chevron site are top of the range but Colin can quote for many different configurations. He can do an integrated based on the Tent Labs volume control and Hypex modules for example.
http://www.chevronaudio.co.uk/html/amplifiers.htm

 

[Cereal Killer]

Interesting stuff. So am i right in understanding class D and a full on digital amp like lyngdorf TDAi2200 are two completely different thing? And if so what exactly is a fully digital amp?

 

[PigletsDad]

Class D usually used to describe analog in, switching power stage.

Full digital means digital in. Depending on details of implementation, there may or may not be a small signal analog representation involved.

 

[Cereal Killer]

so are all switching amps class D? like chord and linn for example?

 

[muzzer]

Aren't the Karan and Accuphase around $6000 new, not exactly cheap.

 

[Jonboi]

Interesting stuff. So am i right in understanding class D and a full on digital amp like lyngdorf TDAi2200 are two completely different thing? And if so what exactly is a fully digital amp?

Not really completely different operating topologies, no. But a fully digital amp, such as the TacT Millenium, and the Sony S-Master Pro, provide what is in essence a fully digital path from input to the output loudspeaker filters, as they amplify a PWM pulse that is derived from a digital bitstream, i.e. 1's and 0's, rather than an analogue waveform as in the case of Bel-Canto, ICE power technology etc.

At the end of the day, I think properly implemented the differences are likely small; pure digital, feedback less designs can seem more 'pure' but, because of the way the output filter interacts with the impedance of a connected loudspeaker, the damping factor of the amp is high, and the frequency response will also vary by very small amounts according to the connected speakers impedance load. For instance, on paper, my amp will drop in F/R by about 0.5db at circa 20k, depending whether it is seeing an 8 ohm, or 4 ohm load re the speaker.

On the other hand, analogue Class D, such as ICE power, uses global negative feedback schemes, has lower distortion figures, better damping, and I would expect it to have more grip in the bass, and be more or less not affected in it's character by whatever speaker you connect to it. One could argue that it's less 'pure' in it's signal path, but that the extra grip and drive and immunity from speaker loads affecting the overall F/R makes up for it.

However Sony do use feedback in their design, but in the DSP 'pre-conditioning' of the digital bitstream, where they condition the signal to eliminate timing errors and jitter, and at the end of the day it is hard to say which is the better implementation of Class D technology. Certainly 'pure' digital has some advantages as you can run a digital signal from source to effectively the loudspeaker output. This makes the likes of streaming audio from a computer very attractive, as no intermediary DAC is needed; the amp is to all intents and purposes a powered DAC in and of itself.

There are minor drawbacks to both approaches as I've mentioned, but I'm equally sure they will be ameliorated in time as further advances in the implementation of the technology are developed.

HTH

Best

Jon...

 

[PigletsDad]

The same techniques can be used in power supplies; at least some of the Linn design are class AB amps with switch mode power supplies. Chords are class D.

There are four (at least) combinations, switching amp with switching power supply, switching amp with conventional power supply, conventional amp with switching power supply, conventional amp with conventional power supply.

Switching power supply is smaller and lighter, doesn't drop voltage under load, but potentially generates interference which may be disliked by other system components. They are also not easy to design.

 

[Jonboi]

The same techniques can be used in power supplies; at least some of the Linn design are class AB amps with switch mode power supplies. Chords are class D.

There are four (at least) combinations, switching amp with switching power supply, switching amp with conventional power supply, conventional amp with switching power supply, conventional amp with conventional power supply.

Switching power supply is smaller and lighter, doesn't drop voltage under load, but potentially generates interference which may be disliked by other system components. They are also not easy to design.

I believe that to be the case re potential interference from switch mode power supplies. Whether that be the reason I don't know, but the big Sony mutha uses a massive toroid/linear power supply which certainly contributes to it's weight of some 62lbs. Lightweight it ain't....

Best

Jon...

 

[Papa Lazarou]

Aren't the Karan and Accuphase around $6000 new, not exactly cheap.

I paid circa £6k for my Bel Canto PRe2 and REf 1000 monos. Then spent a further £1500 on modifications!

The Karan cost me £2500. Admittedly the RRP has gone through the roof somewhat lately. Still I have heard quite a few other amps at less money i'd gladly pick over the Class D offerings.

 

[Cereal Killer]

papa, have you tried any other than bel cantos

 

[Papa Lazarou]

Yes. The Red Wine Audio Signature was my favourite so far (the little integrated that runs off a battery). It sounded pretty good TBH.

 

[Jonboi]

I paid circa £6k for my Bel Canto PRe2 and REf 1000 monos. Then spent a further £1500 on modifications!

The Karan cost me £2500. Admittedly the RRP has gone through the roof somewhat lately. Still I have heard quite a few other amps at less money i'd gladly pick over the Class D offerings.

Is it possible that different geographic locations, and price difference between products based upon their origin/exchange rates etc, might skew results?

For instance, I prefer my digital amp to an NAP500. On the other hand someone else would prefer it the other way around. And why not - they're both extremely high quality products. But I think most would agree the performance envelope is very similar, and it would be down to personal preference as to what one would prefer. BUT, when one is sourced from Japan, and the other from the UK, exchange rates, import duties etc all come into play, as does small scale manufacturing, profit margins of middle men distributors etc. The big Sony was RRP A$6,000.00. (it's an integrated digital amp). On the other hand, an NAC552/NAP500 combo is A$79,000.00. If someone preferred the Naim combo and could afford it I'd say why not, but if they were to opinion it is A$73,000.00 better, I'd say they were a candidate for a comfy building with pink walls, staffed by nice people in white coats.

IMV that's where Class D has a very big advantage generally speaking - bang for the buck. However I guess as usual, the so called high end specialists will jump on it, put their marketing spin on it, and triple the price as per usual.

But that's just me....

Best

Jon...

 

[Cereal Killer]

which sony amp do you have jonboi?

 

[Jonboi]

which sony amp do you have jonboi?

TADA9000ES - sadly no longer available in the West. Japan only update is TADA9100ES - has HDMI and upgraded amplifier chipset.

But not available outside of Japan. The one big drawback with Sony is that they release these statement products, and then sit back on their laurels for a few years. Which is why I like the new Rotels for instance. ICE power technology, great sound, build and finish; sensible pricing. You can buy more or less the same amplifier technology in a say, Jeff Rowland box, or an Bel Canto box, and pay double and triple the price. Well, it is a nicer box, but you get my drift. The sonic differences are likely to be very small. (No offence intended to Bel Canto or Jeff Rowland owners).

Best

Jon...