Harman/Kardon DPR 1001 digital path receiver: Is this the future?

Discussion in 'Archived Threads 2001-2004' started by KeithH, Dec 20, 2002.

  1. KeithH

    KeithH Lead Actor

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  2. Angelo.M

    Angelo.M Producer

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    I have no idea if this thing is the future, but it is one sweet looking receiver, and I'm a sucker for a pretty receiver (and a sucker for H/K). I'll be in line to demo one at home when these things hit the stores, no doubt.
     
  3. Kevin C Brown

    Kevin C Brown Producer

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    I'm still trying to understand how this is *different* from any other reciever/pre pro out there...
    And, does it do Logic 7 on 5.1 sources? [​IMG]
     
  4. Tony Lai

    Tony Lai Stunt Coordinator

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    It has real digital amplifiers?

    T.
     
  5. Guy Usher

    Guy Usher Supporting Actor

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    What are "Real Digital Amplifiers" anyway? Whats the difference between a analog amp and a digital amp?
    Do we finally have an amp whos power supply is the house current???
     
  6. Chu Gai

    Chu Gai Lead Actor

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    Looks like a bringing to light of the Eagle's song...New Kid in Town. Certainly there's been a lot of hype regarding the digital amps and even 'esteemed' publications such as Stereophile have waxed poetic. Everyone loves the new kid...the new amp...but is it better, at least at this stage, than existing amps? I think they have the promise of driving costs of amplification way down...probably to the point where you'll see soundblaster cards pumping out 5x100 watts. Right now they seem to be a bit pricey and seem to have a variety of performance issues. Read a little more about them here. Presently they don't seem yet to deliver logical performance but that's never stopped an idea from succeeding.
     
  7. KeithH

    KeithH Lead Actor

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    Chu, thanks for posting the link. I knew that Sharp makes a digital amp, but it is very expensive. Anyway, I will be watching development here closely. Hopefully more digital amps will become available at reasonable prices soon. I'd also like to see some digital stereo amps too.
     
  8. Kevin C Brown

    Kevin C Brown Producer

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    If anyone would want to post a quick summary of the differences between analog and digital amps, I wouldn't mind... [​IMG]
    (Too lazy *and* satisfied with analog to check out that link...)
     
  9. Danny Tse

    Danny Tse Producer

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  10. KeithH

    KeithH Lead Actor

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    Danny, I forgot that the 'S50ES and 'C70ES have digital amp sections. Thanks. There still aren't many digital amps out there. It looks like the higher-end companies have not yet embraced the technology.
     
  11. Chu Gai

    Chu Gai Lead Actor

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    I look at Digital amplifiers as basically switching amplifiers which may or may not necessarily have digital control of some sort. There is a fair amount of debate about what truly constitutes a true digital amp and the lack of agreement amongst companies will no doubt lead to some differentiation amongst the specific implementations such that 'justification' can be had for charging outrageous amounts of money for what will be penny technology. Some will say, any amp with an SP/DIF is a digital amp. Some say it's those with a switching power supply but conventional amplification circuitry. Or maybe its the other way around. Or maybe both the power supply and the output stages have to be switching. So whatever you're reading is my take on this. Apologies to those who disagree, but I'm generalizing a bit here and i'll leave it to others to hair split matters.
    Switching amplifiers are generally small and as the frequency with which they switch increases, their size and weight decreases. When one considers these particular advantages and contrast them to say transformers that rely upon an iron core, it's no wonder they're rather compelling. Easy for the manufacturer to implement, neglible heat issues, shipping costs and manufacturing costs are reduced, all lead to their attractiveness. They're found in pc's, tv's, etc. and now we're seeing them hit the audio area. Work has even been done on designing digital crossover...name your slopes, tailor it however...the promise of better speakers with better characteristics i think. some speaker manufacturers have even examined the feasability of 'intelligent' digital crossovers that can correct themselves for peculiarities of your room. maybe we can make those white van speakers really sing now! Getting back to the amp thing, the ability of digital amps to model any amp out there shouldn't be underestimated. Musicians have been using digital amps to get the sound out of a no longer made Fender from the 60's and anything in between. No doubt the purists will rail at this and cry 'foul', but a time will come when your soundblaster card can be made to sound like any tube amp out there from any time period.
    So what are some of the issues with 'digital amps'? Well for starters, the fact that they switch is very problematical since it results in transients that make their way to the speakers. To counteract that, low pass filters need to be used. But these filters then increase the output impedence of the amps at the higher frequencies. This results in frequency responses that are tied to the speaker's impedence curves. Just think, you can now have the crappy performance issues (maybe not as bad) as SET amps and still get gobs of power! No wonder the Stereophile comix like them [​IMG] Keep in mind, that at least at the present time, these filters are needed in order for the amp to comply with FCC Part 15 EMI rules. I certainly haven't surveyed all the vendors out there, so probably there's some that find ways around this.
    The above paragraph touched upon frequency response issues with digital amps. To get a better idea of what's going on, let's look at two amps: one digital, the other linear.
    http://www.stereophile.com/fullarchives.cgi?253 look at figure 1.
    http://www.stereophile.com/fullarchives.cgi?245
    now why Stereophile likes the digital is beyond me...new kid in town? sufficiently high price? you be the judge.
    Now digital amps can invariably drive a low impedence load, like ML's or other planars where dips below 2 ohms and even 1 ohm are possible. Not to say there aren't switching mode amps out there that have issues with low impedence, but it SHOULD not be a problem provided the manufacturer wants to spend a few extra dollars.This is a bit more difficult with linear amps but certainly it can be done. In fact, there's oodles of car amps that routinely drive 2 ohm or so impedences using con. Depends on the implementation right?
    If one refers to the two links above we can see that both amps have some degree of IM distortion but they're different. Is one better than the other? Dunno...if it's below the threshold of audibility does it matter? Also in the same two links the amount of power delivered at 2 ohms can be found. In this particular example, the two amps put out roughly the same amount of power although at low impedences, the switching mode can only produce about 1/4 the power.
    My overall thoughts on this is that this is interesting technology, but still not mature. It's a bit telling, at least to me, that the absence of published specs suggest the manufacturer's recognize there are issues such as I've mentioned above. Spec's ain't everything people say, but leaving them out has to make you question things. At least I do. Eventually I think we'll see, in our lifetime too, switching amps that give performance that rivals and even equals that of conventional amps at significantly lower costs. My gut feeling is that they'll be looking at increasing the frequency modulation beyond where it is now and perhaps then some of the issues that've been touched upon will be non-issues. I even see third party products, perhaps controlled by something like a Palm device that'll have various tube performance parameters that can be downloaded. Won't that piss off the 20,000 tube dudes? Then we'll be in agony won't we? We'll have amps that put out 5 kW into 1 ohms and only have to weigh a few pounds. Cases will be made of plastic or graphite fiber, maybe spray coated with anti RFI/EMI solutions. Of course we can always toss in some depleted uranium and get that weight back up, right?
     
  12. Kevin C Brown

    Kevin C Brown Producer

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    Chu- I have to read your post more in depth, thanks!
    I presume that the new PS Audio HCA amp is digital then. I already have a bad taste for that one, because even though Stereophile liked its sound, the guy who actually did the measurements for it was "disappointed". And then a whole bunch of them showed up on the used market.
    And I believe that class H is also a switching power supply. But my uninformed knowledge tells me that class H only shows up in cheap receivers... [​IMG]
     
  13. Chu Gai

    Chu Gai Lead Actor

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    another thing that I 'think' you'll see with switching amps is an increase in harmonic distortion introduced into one's power lines. To get an overview on this harmonic distortion, consider the following link. This seems to be something that occurs whenever one throws any kind of switching power supply on the line. And if I'm correct, as the frequency of switching occurs, that'll change the distribution and magnitude of this harmonic distortion, moving it into higher multiples of 60 hZ. Now for some companies that are out there making AV equimpment, the presence of this, which is admittedly low, is likely not a problem with regards to equipment interference. For others who know. I guess we'll probably see different approaches, such as were mentioned in the link above to try and mitigate it. For anyone who's ever read some of PS Audio's website, they publish some harmonic data that they took next to a PC setup. Then they show you how wonderful their power plant regenerator is as it eliminates this, all the while loosening your pursestrigs. Wouldn't it make more sense to save your hard earned cash and just remove the PC from the power line? To me, it's rather convenient they chose that scenario rather than a different one don't you think?
    I don't know what PS Audio charged for that amp. Far as I'm concerned, it wasn't worth it and I still see that technologoy as not ready for prime time. Time though moves quickly in the digital world and i've got a feeling it won't be long before they start to measure a whole lot better. Like I said, I sure expect to see high power output sound cards in the not too distant future. That'll drive the costs down for sure. Now if only esteemed audiophile designers would learn how to make a product that deals so exceptionally well with EMI as a soundcard does, we just might have something.
     
  14. Justin Lane

    Justin Lane Cinematographer

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  15. Kevin C Brown

    Kevin C Brown Producer

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    Justin- Is that right? I couldn't tell if you were joking or not...

    If true, wow...
     
  16. Chu Gai

    Chu Gai Lead Actor

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    if you read that link from harmonic tech, you'll see what the negative effects of harmonic distortion are and i'm not talking about issues with sound or video quality.
     
  17. LanceJ

    LanceJ Producer

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    "Class H" is not the designation for an amp using a switching power supply.
    "Class H" is an amplifier utilizing two voltage rails. This is so that, at least in Technics receivers, they run cooler than their older "New Class A" amp designs. One voltage rail is used for low power conditions; the other is tapped when an explosion or heavy bass needs to be reproduced. Both designs still use a modified class "A" amp design, which is the cause of their high heat output even while idling. I used to sell HT equipment for three years & Technics was our most reliable brand--so much for their supposedly crummy heat sink construction!
    Here is a hi-end digital amp manufacturer that gets good reviews: http://www.tactaudio.com/
    LJ
    (A satisfied Technics SA-DA8 receiver owner)
     
  18. skip marr

    skip marr Stunt Coordinator

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    Regarding the HK digital unit, all I have read (and some from the inside) is that:

    1. The sound is pristine - no audible distortion.
    2. No slew or negative feedback issues to deal with.
    3. The bandwidth is more than covered (historical HK feature).
    4. The footprint is smaller.
    5. The power and amp headroom is fantastic.
    6, And most important - the heat is not an issue.

    Anyone who doesn't think this is the future of amplification as we know it needs to just stand in line for the already substantial discounts being passed on to the consumer for current (and soon obsolete) products. Yamahs, Onkyo, Integra, Marantz, Denon, PE, and even Rotel are all dealing as I have discovered in my research and shopping for A/V units since November. Anyone paying full retail should get a receipt and re-negotiate. HK has a real advantage as they keep their lines short and to the point. The others can't turn quite as quick because they are over-sku'd. Good luck to anyone who can't wait!!
     
  19. Lewis Besze

    Lewis Besze Producer

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    While I agree this could be the future,I have a feeling that the "usual suspects" who generaly favour analog over digital will declare this as a "looser" proposition.
    I think that Plasma tvs and digital amps are the future,if not the immidiate one.
     
  20. Kirk Gunn

    Kirk Gunn Screenwriter

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    So when will this baby show up as a OneCall special purchase on the HTF Deals page ?
     

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