Digital Amplifers vs Analog Amplifiers

[Bing Fung]

As digital amplifiers become more main stream are they soon going to replace the brutish heat sinks, huge power supply and capacitors required in an analog amplifier?

Digital amplifiers are said to offer more efficent power use and management because they do not have to supply power over the entire analog wave form, rather it amplifies in typical digital ON/Off fashion once it has converted the wave form into a series of digital pulses. This allows less power consumtion and less heat build up, thus no more Monolithic blocks comprised of power supplies, capacitors and heat sinks required for a 7x200W chassis.

So, are digital amps really the next best thing, or will they always be shunned by the Audio purists as having no soul to the sound?

When you stop and think, the Purist still cling to Tube amps and vinyl media with groove harmonics :roll: Will the analog amp live forever?


You may ask what is the purpose of this rambling....? Well I'm just wondering if a person should put down good money on an Analog amplifier these days or adopt a wait and see attitude....

I already have enough analog amplifiers to create a decent system, nothing breathtaking, still decent....

[Jariten]

Not many around are they?

they must have an interesting electronic signature...
Didn't Onkyo make a Digital Powr amplifier?

I still prefer the massive Heatsinks and Huge Torroidal transformers and Hugs Caps ^_^;;;

[Bing Fung]

Hey Jariten, I'm with you. I like the huge heatsinks, Caps and Power supplies as well. :T

I was wondering if on a technical aspect they have the possibility to have a cleaner signature due to the fact that they will be only amplifing audio data.. I don't know?

They could be a few years out before the trickle down make it main stream

I read Yamaha is releasing Digital amps this year.

Yamaha Digital Amplifier

Global Source Article

[JonMarsh]

There are many possible ways to make a digital amplifier- some being not too expensive, some being very expensive in principle.

Most existing "digital" amplifiers are not really digital, but should be better described as pulse width modulation switcing amplifiers- they don't use any type of digital signal that even remotely similar to what's in a CD player, for example. This applies to amplifiers from QSC, Crown, LC Audio, PS Audio, etc.

A few try to build a power stage using either one bit concepts based on DSD (Sharp, for example), or actually use a modulator which is in essence a power DAC. These approaches are more expensive, and like the PWM type, have pretty high levels of output switching noise; enough to make RFI filtering a problem, and enough that the output filter networks cause considerable level interaction with varying loudspeaker loads. Improvements are always being made; the B&O ICE modules reportedly being among the best sounding of this technological direction.

Class D amps tend to have different kinds of colorations and interactions than class AB amps; a well designed Class D amp may be sonically superior to a mediocre AB amp. I personally prefer Class D amps running at relatively high switching frequencies, in full bridge, with two or more stages in quadrature, and no conventional feedback taken from the output. But then, I'm an opinionated S*B; I have built several Class D amps, and had papers published in venues like AES conferences and journals.

I haven't heard a Class D amp that beats the best AB circuits I've heard, but who knows, some day? The complexity of doing Class D well tends to limit it either to high output powers, where the additional control complexity is justified by the power levels and efficiency, or to applications where efficiency and waste heat are major considerations, like subwoofer amps. As dedicated control and modulator chips become available, the proliferation of Class D amps should continue; in princicple, all one should need is the conditioner/comparator/modulator chip, a half bridge driver chip, and the power output devices and clamp diodes. Ahh, but the devil is in the details...

Regards,

Jon

[Bing Fung]

Jon, I know that Soundstream made a few digital amps a while back. One of them was as small as a Feddback destroyer, yet put out 400 w/ch and was bridgable to like a 1000 w.

I was under the assumption that all Digital amps were Pulse Width Modulation (PWM), not Code (PCM) modulation.

[JonMarsh]

The Soundstream's have to be using a switching power supply, too, to achieve that form factor. Crown BGA series use a conventional supply which in comparison is relatively low tech, but has higher peak current capability. Switch mode power supplies tend to have pretty good regulation until they hit the current limit, then poof - shutdown or foldback.

I have some TriPath modules, too, that I've been meaning to tweak up and play with (They're used by Bel Canto and others), but I just haven't had the time available- they'v been sitting in a box in the closet along with power supply parts for almost two years!

These days, all my effort has been focussed on either the speakers, or on the Aragon Xmod project, which is a total rebuild of the audio and power supply circuits for Aragon amplifiers (8002, 8008 series, and Palladium), using non loop feedback circuits with a heavily biased AB output stage (class A to between 50 and 100 watts). That's entering PCB layout for the third design iteration. I think this will be the one I go with... 8)

~Jon

[Bam!]

Bing!

We sure are busy in the new forum ain ? :lol: :T

Panasonic has come out with one... the XR45!


Here's a quick review on it :Few audiophiles will stumble on and embrace the XR45. And certainly not in public.

“Say George, I just traded in my $8000, 200 pound Krells for a 9 pound, 3" high Panasonic receiver. Would you like to come over and listen to it?”

“No Tony, it’s OK, I have to cut my cats nails right now and then my wife and I are going on 2 year world tour so you don’t need to try calling me again. Ever.”

Even Panasonic isn’t making it easy. Fire up the XR45 out of the box and it sounds like the cheapo receiver you expect it to be. Thin sounding, with no bottom end whatsoever. I have worked with enough TI digital amp evaluation boards and prototypes to know that the sound had to be better than that.

The factory defaults appear to be surround sound with some type of trick “enhancements” and a 100Hz subwoofer filter. The factory obviously assumes that it will fulfill it’s lowball mission of driving a cheap set of speakers and subwoofer in a “venue” (hall, movie theater, tavern, grotto ) surround mode. After fighting my way through the menu system for 90 minutes, I was able to arrive at a simple, unfiltered, modeless and unenhanced stereo configuration.

The result was a truly amazing bottom end normally delivered only by the likes of Spectron, Classe, Bryston etc.. Deep, powerful bass with superb pitch definition out of a 9 pound package. It was many days before I could stop gazing in wonder at the XR45 every so often during listening sessions. Even with my background of digital amp evangelism, the hearing and the seeing requires a radical mental re-alignment.

[Andrew Pratt]

Interesting question Bing. I know that digital amps are being looked at seriously in the industry and you can't really blame them if they can be made lighter and smaller for shipping...which is esp. true if you're trying to pack in 7 high power amps, a tuner and other components etc into a receiver box.

From what I've heard the digitals can sound very very good when done right but they don't typically sound like traditional solid state amps...and very different from tube's. It'll be interesting to see how the audio community takes to them given our preference for large heavy box's with large impressive heat sinks on the front but sooner or later I bet these will be where the industry goes as we demand more and more amp channels at higher and higher power ratings.

[aarsoe]

Well, in my own humble oppinion I dont really care what kind of technology my amp is using - as long as it sounds good. Having said that, there is absolutly something about not wasting space and energy on something if it can be avoided.
Used to have a power amp that was rated as 2x100W in pure class a. It sucked up something like 500W just when turned on - and that was before playing music. The top of it was so hot that you could not touch it without discomfort.
Did it sound good - yes, but I still got rid of it, as the electricity bill simply became to high.. :M
I am sure that people said the same thing when the majority of the industry moved from valves to transistor..

Also, dont know if anyone have read reviews of the fairly new Bang and Olufson speakers (Beolab 5) using ICEpower.

http://www.bang-olufsen.com/sw887.asp

They (the reviewers) claim that they beat almost everything out there and they are based on digital amps. Infact they have 2500Watt for each speaker - and they are tiny compared to something like Wilson Watt/puppy and similar..
Must admit that when I listened to them in a really bad demo enviroment, they just sounded about 100.000 times better than my own equipment..
The sad part though is that they cost about 17.000 USD
- but hey, then you dont need any power amps.. :T

[Bing Fung]

Andrew, I also feel nomatter how good digital amps could be, they probably will be shunned because they won't have the huge overdone stuff that esoteric Audio philes typically like.

Bam, so the reviewers liked the XR45? Seems like it....


Arrsoe, interesting B&O stuff.


Jon, why aren't Pro amps like the Crown 1000 Watters and Samson 1000W amps used for main speaker systems? What is fundamentally wrong with using these relatively cheap W/$ ratio units for a stereo or HT set up?

Are they not capable of musicallity, transperency, imaging... (__________ insert Superflous adjective here) reveling sound?

If the answer is yes to the above, why? (Big scary Electrical/Sound Engineering explanation coming up, *brace myself*, empty the mind to receive large blocks of complex data )

Just teasing you Jon, give it to me straight :W

"Aragon Xmod project" ??? Thats awesome when the factory best (of a good brand name) just doesn't cut it and needs modifications :rofl: True admiration! :T