digital amp for HT? (H/K DPR1001)

[tpg]

I stumbled across this at Circuit City... and thought it looked very intriguing. Digital amps run very cool... and this one does everything I would want. My current receiver gets quite warm... and I have been considering an upgrade anyway...

Has anyone used one of these? Heard one of these? Done neither of the previous but still have an opinion on it? I am interested in giving it a try, but don't want to be stuck with it if it is no good. The reviews on CC seem positive enough... I am not sure if I am in the market for a new receiver or not, but it might be nice. I upgraded speakers, so why not the receiver, too? heh I am open to comments on this... Are the AVR series receivers by HK better sounding?

[JuneBug]

Curious that you posted this today, since I just replied to another thread on digital amps in the 2 channel forum.

I had been intrigued by digital amplifiers for several months now, since reading so many great things about them on other forums. I had been most intrgued by the Panasonic units, but had been holding out for the newer models. These were supposed to come out this month, but they seem to have been delayed. I started to look around, and found that there are several companies that are making these (Sharp, JVC, etc). Needless to say, JVC is not well known for quality audio, so I was soewhat aprehensive.

Then I cam across the DPR-1001. I had previously had a Harman Kardon receiver from the late 80's (HK 385i), and loved the way it matched up with my Heresy's. I was most intrigued about the low-level resolution that these digital amps are supposed to have, and since they were described as working well with relatively insensitive speakers, i was curious to see how thy would do with highly sensitive speakers like Klipsch. The fact that the digital amps are almost 90% efficient in terms of energy consumption was also of interest.

After sniffing around, I found a closeout for them at J&R Audio. They gave me a great price, and I walked away with them.

I have to say that after 3 weeks, I am still impressed. Right out of the box, even without calibration, it sounded great. The 2 channel stereo sound is absolutly incredible. The imaging is rock solid, the have zero noise (at all volumes), the bass is super tight. I could go on, but you just have to hear them to believe it. And that is just 2 channel stereo. Multi-channel reproduction is just as good. I was watching Master and Commander the other night, and it was like the cannons were going off in my living room!

They are also ultraflexible, since each surround mode is independently configurable. The bass management is great, allowing independent crossover settings for each channel, and options for global settings, or independent settings for each input.

My system sounded good with my old receiver (Technics SA-TX30), but it is clearly blown out of the water by the HK. One of the things that bothered me the m,ost about the old receiver was that, like most SS amps, it just did not sound right at the low levels that Klipsch speakers usually run on. I always had to raise the volume to a certain point before the speakers would "bloom" into their best sound. This amp does that at all volumes, which lets me run it comfortably at low levels at night, which is handy when you live in an apartment like I do.

I don't think you can go wrong with this amp!

[tpg]

Thanks for the reply. I was hoping good things were to be said about this unit...

H/K has newer models out... but they cost a fortune. heh This one is an older model... but all the reviews I have read (inucluding yours) have been positive.

I usually listen two-channel direct (no sub) now that I have the RF-3's. It seems my subwoof-age cannot keep up with the new speakers. Go figure... Needless to say, with my current receiver, bass is wonderful once you get it up to really darned loud levels. However, when you turn it down for night listening, I don't have much (if any) bass... From what you said, I take it this receiver is well balanced on all settings, which is a major plus.

I also scanned through the owners manual and saw the individual x-over settings... very good feature. I suppose if I tried, I could even get multichannel music with no subs. heh I am kind of tired of using subs... my more powerful sub's amp has two fans that are insanely annoying. Consequently, it doesn't get used unless I am watching a movie or listening to loud multichannel music, both of which are rare.

I suppose I might have to scrape together my pennies and go out to give one of these a try and maybe pick one up. My local Circuit City supposedly has one... so maybe I could give it a good listen. They are $511 there... plus tax... so more than you can get them for online, but I don't suppose that is too bad... I will get a warranty and exchange policy for 30 days. heh

[Scp53]

tpg, tell us how it goes. Im looking for a amp to power my rb25's and sb3's and a sub preout to my titanic 10". I have a very basic SS stereo receiver. clean sound/power but not what you guys call "clean sound/power". I ve ruled out tubes because of expense and reliablity/longevity/etc issues. maybe a digital amp is the trick??

[richinlr]

About 1 month ago, I bought a DPR1001 at 11 AM on a Saturday. Took it home and spent the afternoon hooking it up. Turned it on and

HHHHIIIIIIIISSSSSSSSSS!!!!!!!!!!!!!!!!!!!!!!!!!

LOUD HISS. Re-checked everything, tried to make some sense of the abysmal H/K manual. No luck. Got REALLY p****d! Unhooked everything, packed it back up and returned by 5 PM.

Went straight to Best Buy, bought a Yamaha, hooked it up exactly the same way. ZERO hiss. Never looked back.

If you have good tweeters (like Klipsch) you ain't gonna like it.

Just my own personal experience BUT I HAD read about the hiss problem with the DPR1001 on other forums and the price absolutely beguiled me. Learned my lesson.

CC also told me that they are having trouble giving these things away.

[JuneBug]

I have had no issues with hiss. I have the receiver connected to Forte I's, a KV-3, and KSB1.1s, and they are dead quiet, in all modes. I had read one other person mentioning hiss (not on Klipsch speakers), but I think that that may just be an individual unit.

I really can't say enough about this unit. It has given me everything I was looking for. I don't think I will be upgrading anything else in my system for a while.

[richinlr]

It may well be a configuration issue. Are you using any of the pre-outs?

I use the front L and R outputs to feed my main two channel pre-amp which feeds my main 2 channel power amp. Used this way I can get the benefit of maintaining my current 2 channel setup and integrating my mains into my HT.

If you are not using the pre-outs and using only the HK amp sections it just might be quiet. However, even the specs indicate that the S/N is about 20 dB less than comparable Yamaha gear.

[JuneBug]

I have the DPR-1001 as the only amplification unit in my system. My sources are connected digitally (CD & DVD - optical, Cable - coaxial) so that the only Digital to Analog conversion is at the output stage.

I think that might be a reason you got bad results. You are daising chaining a bunch of different components to form a long electrical circuit before you get to the speakers. There must be a significant degradation in sound quality by going through so many boxes. Another possibility is that you may be creating ground-loop problems by going through so many boxes.

Also, that completly defeats the purpose of digital amplification.

[richinlr]

1. All audio sources connected to the DPR1001 WERE digital.

2. The pre-outs are supposed to be line-level and capable of being sent straight to another power amp.

3. Only additional box is the pre-amp.

4. I do not feed ANYTHING from my Electro pre-amp back to the receiver.

5. Ground loops do not produce hiss - they produce hum.

6. Yamaha connected in EXACTLY the same configuration results in no hiss or hum. The Yamaha has a 20 dB BETTER S/N ratio than the HK. 20dB is no small amount - set your receiver volume on -20 dB and then raise it to 0 dB to hear the difference in 20 dB.

7. What is the purpose of pre-outs if you can't use them?

8. The DPR1001 (or just about any other HT receiver in the sub $2K range) cannot come even close to my Electro pre and power amp in performance.

9. I do not allow noise or hum in my system and everything is connected in star ground fashion. If a component produces noise it's outta here...

Bottom line: the DPR1001 may be fine if it is the only amplification in your system. Obviously the pre-outs were not executed very well on the HK...

The fact that a receiver that started life in the $1200 range and now can be purchased for $450 says a lot. It is also discontinued. CC can't sell 'em and HK has replaced it with better performing models.

I am glad you are having good luck with it. Again, as a single point of amplification it is probably pretty good.

[JuneBug]

After reading your post, there is only one other thing I can think of - did you have the receiver near a CRT TV set? One thing that I did read several times when I was researching these amps is that they may be very susceptible to RF interference. If the unit was near a CRT, it may have been picking up the electromagnetic field generated by the tube.

I experienced something like this once with my old (analog) receiver. Due to space constraints in my living room, I was forced to locate the receiver relatively near my old 32" TV. That thing put out a wicked EM field. I could feel the hairs on my forarms stand up a foot and a half away from the CRT tube. It created a really annoying whine that would not go away no matter what I did. I eneded up getting an outboard digital processor to connect my sources with fiber optic cable, and that finally got rid of the whine.

As for the discounted price, I think that is more a function of HK quickly coming out with newer, more powerful units, and stores needing the shelf space for these, rather than any inherent problems with the DPR-1001.

[Griffinator]

The Panasonic XR digital amps are what inspired HK to get into the market. Unfortunately, Panasonic actually put some major effort into their offerings, while my sources say HK rushed theirs to market just to get a slice of the action. It doesn't surprise me, the way Harmon Audio has gone with most of their brands, that theirs is an inferior product.

I still say the Bel Canto Evo's are the only choice for the serious audiophile - but if you don't have the dosh, and still want to experiment with digital amps, then the Panasonic is the way to go.

[tpg]

Panasonic? Really?

I have never liked them much.... I guess it is a personal bias. I'll look into them, though, if they are really better.

[Griffinator]

In the price range, they are.

If cost is no object, the Bel Canto Evo's are the way to go...

[richinlr]

I have a 65 in. Hitachi rear projection unit. Receiver was/is placed on a shelf above the television. This would place it at least 4 feet above and away from the RF generating parts of the television (in the bottom of the TV). So that should not be an issue.

Since you are not having the noise problem and not using the pre-outs and I did have one using the pre-outs, I cannot help but think the pre-outs themselves are the issue. And they were just thrown in as a need to compete (probably used some cheap op-amps to implement). When I was looking for an HT receiver with pre-outs, one thing quickly stood out. For reasons I could not fathom, the price of admission for a full complement of pre-outs was $500 minimum for the receiver. None of the cheap ones have them. However, every receiver $500 and above has them.

As far as RFI goes, I have a problem with ANY manufacturer (including the real high-enders) not taking this issue into account when they design something. Good gear almost always includes a 'ground plane' (foil everywhere)with the circuit traces designed to specifically avoid RFI on their circuit boards nowdays just for this reason.

In this wireless world, RFI is as prevalent as pollution. Get a good multimeter with capability to measure millivolts. Set on AC scale and simply hold the probes in the air and look a the c*** it is measuring. Usually in the neighborhood of .25 to .35 mV...

Go to your local CC and ask them how the DPR1001 is selling. My local CC said that it basically has done nothing but languish on the shelf. And I suspect that the report of noise on other forums has caused the lack of sales.

[JuneBug]

The RFI issue I mentioned appears to be inherent to all PWM amplifiers, not just this one. If I remember correctly, it has to do with the way that filtering is applied to remove the high-frequency artifacts from the D/A conversion in the final stage.

I am not surprised that the HK isn't selling well at CC. This particular unit has been available since last year, but I had not heard anything about it. Even though HK won an Engineering and Design award at the 2003 CES for the DPR-1001, it doesn't seem like they put a lot of effort into marketing this unit. If you look around for information on these digital amps, you will continually run across references to the Panasonic units, and occasionally the Sharp 1-bit designs, but practically nothing about the DPRs.

As for the quality control problems you mentioned, all I can say is that I knew they had some issues with their stuff in the early '90s, but things seem to have gotten under control lately. I knew about QC issues with their CD players, because I had read a lot of complaints about the 8550 changer.

I can honestly say that I haven't had sound quality this good coming out of my system since the days of my my old Denon PMA-590 integrated amp. Even my wife noticed the difference, and she usually thinks that I am insane when I try to talk to her about subtle changes in the system from small tweaks.

[tpg]

Hmm... I am not too certain of going with this receiver... but I might check it out at my local CC if I get some time.