All-digital path receiver

I posted a similar question on the Home Theater forum, but this may be a more appropriate venue:

I am curious about the Harman Kardon DPR1001 'all-digital' receiver (they apparently have more all-digital models in the pipeline, too). The salespeople rave about how cool they run, the superiority of the digital path, and the compact size. But if the digital path has to be converted at some point to analog (like at the speaker terminals), what's the advantage? For example, if I connect an SACD player to the 5.1 inputs, I would be using analog inputs, and (hopefully) bypassing the digital altogether.

This receiver is being phased out and so it can be found for $500 or so, making it a very attractive upgrade. Has anyone used this receiver?

I noticed that there are several people who have questions about the HK DPR all-digital receivers. Is there really no one out there who's auditioned one of these?

I haven't heard these new digital amplifiers, but they convert to analog in a new way. Basically instead of having an analog voltage waveform there is a discrete of/on set voltage which is switched extremely fast - it's ambiguous whether you would call this waveform analogue or digital. The signal is put through to the speakers and the switching is so fast the speakers move as if it were a continuous waveform. You could say that the speakers do the digital to analog conversion!

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Originally Posted by CSMR

...you could say that the speakers do the digital to analog conversion!

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This is very interesting. Is this bad for the speakers? Do some speakers handle this better?

Actually there may be something before the speakers which smooths the signal somewhat. I don't know much about this. If you go to
http://www.audiocircle.com/circles/v...20avd&start=70
there's some discussion and a link to sony's technical info about this.

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Originally Posted by nightflier

...I am curious about the Harman Kardon DPR1001 'all-digital' receiver (they apparently have more all-digital models in the pipeline, too). The salespeople rave about how cool they run, the superiority of the digital path, and the compact size. But if the digital path has to be converted at some point to analog (like at the speaker terminals), what's the advantage? For example, if I connect an SACD player to the 5.1 inputs, I would be using analog inputs, and (hopefully) bypassing the digital altogether. ...

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I have a Panasonic SA-XR25 receiver which is "all digital". The digital to analog (DA) conversion is at the output stage of the amplifier, i.e. just before the signal is sent to the speakers.

If you connect your source via a digital input, (optical or coax), the signal is processed by the DSP (digital signal processor) and sent to the amplier in entirely in the digital domain. If you connect via analog inputs, including both stereo and the 6-input connectors for DVD-A or SACD, then the signal is converted to digital, then sent to the DSP and on to the amplifier.

Most non-digital AV receivers have a "direct" switch that lets analog signals by-pass AD conversion and the DSP and go directly to the (non-digital) amplifier. However this does not apply to "all-digital" receivers or amps since the immediate input to the digital power amp section must be digital.

All digital amps are starting to come of age and it looks to be an interesting future for them. A friend of mine (an audio lunatic) just bought a 500 WPC all digital Yamaha amp to drive his B&W 802's. Pricey unit - but being compared in audio rags to big SS amps costing 4 to 5 times more.

It is definitely the smallest amp of this kind of power I have ever seen - with the lowest power usage to boot (due to the inherent efficiency of digital amps).

A whole host of all digital amps seem to be arriving at the moment - some very inexpensive indeed (usually around 100 wpc).

Frankly I am currently watching rather than buying. Let the market settle a little and take the plunge when it has matured a bit more.

If I understand this correctly digital amplifiers use PWM to produce a voltage. Then the speakers inductance, resistance helps to lower the THD to an acceptable level. Wouldn't that speakers resistance to inductance ratio have a huge impact on sound quality. Would electrostatic speakers sound terrible with a Digital amplifier? I am not trying to "diss" digital amplifiers, I think these are the future of audio. I am just curious as to how they work.

I purchased the HK DPR1001 from J&R for just $429 with free shipping and no tax (I'm in CA). I am comparing it to the similarly priced Onkyo TX-SR601, which it replaced and that I really liked. Everything being exactly the same, here are my observations:

- SACD via the analog inputs sounds just about the same. Even tested this with my laptop and a spectrum analyser.
- Coax-digital input sounds a tad better. There seems to be more breadth in the music. It also sounds much crisper, although this could be coloration too. But I do like it better.
- I can''t figure out how to get the 5.1 analog inputs to work with the component video inputs for the DVD. It seems that it always associates the DVD with the coax input. If anyone out there has a solution, please chime in.
- The 5.1 inputs are completely independently assignable (see previous point) something that was not the case on the Onkyo and for me a real pain in the rear.
- Zone 2 output is only via speaker terminals, the Onkyo has RCA outs. That said, the HK can play 5.1 surround in zone 1 at the same time, something the Onkyo could not without an external amp.
- HK can do 7.1 (if there is no zone 2)
- The front A/V inputs can be switched to outputs. Now that was cool: I recorded onto my camcorder from the front connectors.
- Despite the promises, this receiver does run hot, albeit, not as hot as the Onkyo.
- Despite the 50 watts per channel rating, this is 50 watts to each of the 7.1 speakers, something the 85 watt Onkyo cannot do. I have yet to reach a performance limit on the HK, and I've been playing it very loud...
- There are two remotes, and the large one is pretty full-featured with LCD and backlighting. It does revert back to the receiver after 30 seconds, though, which is annoying.
- The read-out on the receiver is actually readable from across the room, I always had trouble with the Onkyo and had to switch to the onscreen display everytime.
- Neither receiver up-converts video (and the on-screen display) to component video.
- The HK has 7.1 pre-outs, which you can connect to an external amp.

If you have questions, feel free to post here. For the price, I just can't imagine a better receiver. If you need more power, HK has 100 and 120 watt newer models that I'm sure will have even more features, but for me, this is a fantastic receiver.

I will be borrowing a 180 watt Adcom behemoth of a receiver from a friend's house to see what that will do, but until then, I'l be dusting off some old CD's. (Now if I had the room and the money, I'd like to throw some Outlaw 200 monoblock amps under this receiver and crank out 1400 watts throughout the neighborhood. Wouldn't that be a kick in the pants!?)