Class D-Amps/ receivers

[Jfconrow]

does any receiver have a a good D-class amp?

 

[furrycute]

Why would you want a class D amp?

Class A is the most desirable. Then there is the class AB. Then there is the class B. Below class B, those amps are only suitable for powering subwoofers.

Of course there are the digital amps using class D (or it is class T? I forget) amps. That's another story.

But most conventional amps use class AB amplification.

 

[Jfconrow]

well Class D receivers are smaller, more efficiant, less heat, and some have thd below A or AB receivers. Plus their new and cooler

 

[Rob Babcock]

Two model lines seem by popular concencus to stand above the crowd: the JCV RX-F10 and the Panasonic X-45. The former is said to have a superb analog section while the latter utilizes a TI chip that keeps the signal pure digital from input thru output. One aquaintence at AC uses his JVC with a $4,500 digital front end and is extremely satisfied. Modded versions of the Panny are said to hold their own against amp/preamp combos costing 4-5X more.

This is a case where not judging a book by it's cover is wise. The new digital recievers may be small and light, but they definately punch well above their weight. The JVC has even been reported to be capable of driving Magnepans adequately!

 

[furrycute]

I heard the new JVC shelf system with those wood cone speakers about a week ago. I am not sure if it was the wood cone speakers or that digital amp, the sound was amazing for a shelf system with such tiny speakers.

Where can you get that JVC receiver? And how much does it cost?

 

[Rob Babcock]

Quite a few places online sell it. Try J&R. Depending upon where you find it it's around $250-300. The slighly older model it replaced is also supposed to be superb, albeit with 5 channels instead of 6. It'll only set you back $200.

For a cheap taste of Class-T, try a Sonic Impact for about $30. I use a Tripath powered Griffin Powerwave with my internet PC (driving a pair of JBL HLS-610s) and I've very happy with it. That'll set you back about $100, but it's also a soundcard and a good 'phone amp.

 

[Francious70]

I have to agree that for Home Audio where power consumption is not an issue, don't go with a class D amp for anything other than a subwoofer.

Check out this page for a good amp class tutorial: http://www.bcae1.com/ampclass.htm

Paul

 

[Az B]

Although Class D amps run cooler and more efficiently, the big draw is low cost. They are far cheaper to make and therefor the manufacturers want you to buy them. The profit margin on mid fi is dropping like a rock and marketing Class D amps for the same or more money than typical A/B designs is simply good business.

They don't sound any better.

 

[Yamahaluver]

I have had the chance to hear the Panasonic class D receiver extensively and can tell you that it is truly nice, has excellent definition and you cant find a better deal at that price.

 

[Rob Babcock]

Whether they "sound any better" is perhaps debatable, especially given the general belief at AH that all amps sound the same. The real point is they don't sound any worse, and certainly as good as anything else you're likely to get anywhere close to their price point. No offense meant, but I have a sneaking suspicion that anyone trying to warn you off of them probably hasn't heard one and is just parroting old superstitions.

Aside from better PS and overall parts quality, many of the modules in those receivers are the same ones used in the kilobuck offerings from Bel Canto and others. I think the Spectron amps might use a proprietary chip, but at the heart of most of the expensive digital amps is the same module built by a handful of companies, much as TI makes all the DLP chips. B&O, TI, Sony & Tripath are the main chip builders. Pop the hood and see what's underneath.

I advise you to try one for yourself. There are several places to buy one that will allow a return if you don't like it. The price is right, though, and it's definately worth looking into. YMMV of course.

 

[Audioholics]

given the general belief at AH that all amps sound the same.

Don't put THOSE words into our mouths. We would most certainly disagree with that blanket statement.

 

[Az B]

I also never said digital amps sound bad. I simply said that the primary motivation for offerering them is price, not sound quality.

I would also disagree that all amps sound the same.

I would, however, agree that properly constructed solid state amps in the same price range will generally have negligible sonic differences.

 

[nate dog]

class d amps...

Although not a reciever, NHT is using class D amps on its upcoming Xd line of speaker systems (you supply the pre amp). Being that this is their flagship speaker line implies that class D amplifiers can sound outstanding. To bad its way out of my price range

 

[furrycute]

How do those digital amps compare to a class A amp? I have heard both on separate occasions hooked up to different speakers. But have never compared the side by side. Just from memory, I like the digital amp's faster sound.

 

[Rob Babcock]

Run a poll then, Hawke. I'm not claiming all amps sound alike, nor claiming you think so either. But I think a pretty good majority of the AH membership would probably agree that, within their linear range, decently designed amps will sound the same. A cursory examination of the amp threads here will show that aside from a few vocal audio mystics, most guys here seem to come down on that side of the issue. I'll take "negligible sonic differences," as another way of saying "sounds pretty much the same." And anyone who knows that amps sound drastically different; well, I know where you can win $10,000. Step up and put your money where your mouth is.

Anyway, I don't think digital amps do sound precisely the same. Of course, I haven't scientifically tested that feeling, either. The digital units I've heard far outperform SS or tubes in their price range, IMO.

News flash- pretty much all gear on the market was designed to turn a profit. Santa isn't real either. Sorry to shatter anyone's cherished illusions that audio manufacturers are motivated solely by the desire to benefit all mankind. That said, one maker of digital amps, Solar Hi Fi, provides an environmental impact statement for every product they sell. I'm not a bunny hugger so I don't know all the lingo, but he engineers "green products." Digital amps use a fraction of the power of SS or tube amps and are much more efficient. May not matter to you but it does to some people. How many SS or tube models can wear the "Energy Star" badge?

Bottom line: it's a free country, but if you're answering this thread based on hearing a class D amp in a buddy's car 5 years ago or what you read on some web site 3 years ago, do us all a favor and listen to a new one before you make another post.

 

[WmAx]

Two model lines seem by popular concencus to stand above the crowd: the JCV RX-F10 and the Panasonic X-45. The former is said to have a superb analog section while the latter utilizes a TI chip that keeps the signal pure digital from input thru output.

Hmm. Then my cd player has pure digital output on it's analog outputs. LOL.

PCM input must be converted to PWM for output to the speakers, but in essence this is the aproximate equivalent of a DAC if you minus the anti-alias filter.

But seriously, how/why does it matter? Or was this just a feature proclomation?

-Chris

 

[Rob Babcock]

That's complex, but it does remove one conversion cycle. You could say the module is the DAC, but in a sense your speaker is part of the DAC, too. To clarify, the JVC has an actual DAC section that feeds the amp, where it's modulated by the amp. The Panny can omit this conversion, with the digital amp module "converting" the digital signal. The signal stays digital thru all DSP stage right up to the amp module.

 

[Rip Van Woofer]

AFAIK, the knock on Class D (including digital) amps so far has been that they tend to have higher distortion than conventional analog designs. Whether the distortion is audible with normal program material at normal listening levels is another matter. But it is sure to get better - and the recent THX acceptance of two digital amp designs indicates that progress is already being made.

Supposedly my HK DPR 1001 uses digital amps, but as of now (for reasons unrelated to this thread) I'm running my speakers thru a conventional outboard power amp via the preouts. But I'll be changing that after the New Year so if there are any sonic revelations I'll report back.

Of course, I'm a card-carrying member of the "all amps (with certain qualifications) sound alike" club, so don't hold your breath!

Now, just on a common sense basis it seems to me that keeping the signal digital all the way to the speaker outputs is the way to go. But of course, the only real barriers to that (for those of us who prefer our components in separate boxes) are legal and political, not technological.

 

[Rob Babcock]

You hit the nail right on the head, Rip. It was technically possible to keep SACD/DVD-A signals digital long ago, but legal wrangling has kept it out of reach for most people. I've been a big fan of both formats, but even I must admit they're doing all they can to kill it. My most recent trip to BB revealed an SACD section that's shrunk by 50% over the last four months. The DVD-A section is about the same, but it was smaller to begin with. It looks like BB is giving up on SACD, and that's a bad sign. If it tanks, Sony better realize it's wholly at fault.

I was pleased to see digital amps getting TXH cert'd. While I don't consider THX the "be all, end all", or even really important, it's a sign that the amps are getting more linear. I'll agree that lower distortion is better, all else being equal, but there's a point where lowering it won't be audible. The Tripath has a little more distortion than, say, B&O's ICEPower chip or the TI chip, but ironically it's the one that's getting the most effusive praise from the audiophool community.

Many peoples only experience with digital amps has been in cheap crappy car systems. That's like eating chow mein at the mall food court and determining you don't like Chinese food. Obviously everyone has their biases and preferences, and that's part of the hobby. But I think digital amplification is poised to sweep the market. Certainly it's advantageous in places where size, power consumption, low heat & low cost are necessary (eg inside TVs, boomboxes, clock radios, etc), but imagine the other applications. Think of an HT with all powered speakers barely larger than passive ones. Or a "flagship" reciever in the same space as a conventional SS one.

At the high end, amps like the Bel Canto Evo series and the Spectron Musician III have garned near-universal rave reviews from every publication that's reviewed them. Sure, it's the cheapo ones that are at the forefront of public awareness, but like everything, you can get a no holds barred version if you like.

 

[Rob Babcock]

BTW, BFConrow, although I haven't personally heard them under ideal circumstances, a few guys I know have raved up the new Sony ES receivers. One guy in particular who's works as a recording engineer tells me he's stunned by his new STR-DA5000ES. It uses a proprietary "S-Master" amp module to delivery 170 x 7 into 8 ohms, and purportedly keeps the signal in the digital domain right up to the amp stage. I've heard the digital Sony's, but only in a retail setting- they sounded just fine but I can't say I had any chance to listen critically.

The Sony's seem to be fairly controversial, though. Many love them, but I've heard of quite a few that don't. It's hard to tell if they just hate on Sony in general for being a large company of if there's legitimate problems with them. Best to try to arrange to hear them for yourself.