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Denon DRA-800H Review (Stereo Receiver)

ttt

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@amirm :
I'm absolutely not sure you measured the main AKM DAC at ZONE2 output.
There are 2pcs PCM5102 TI stereo DACs on the board (right up next to AKM) for ZONE2 and Subwoofer outputs. These are responsible for driving the above 2 outputs, even when the main zone and zone2 plays the same music or different. It is necessary use separate DACs there to be able to provide you can also play back separate sources in the MAIN ZONE and ZONE2 same time. According to see a bit closer the main AKM DAC, there are numbers (2-4) of NE5532 opas around there, because of dual-differential DAC configuration needs many opamaps for I/V and filtering, so the number of NE5532s are OK, no other ones for ZONE2. IMHO, because of the ability to drive simultaneosuly the MAIN and ZONE2 there are no separate digital and analog signal path routing/switching (I mean using the main DAC for all zones output - and separately analog routing of signals, different DACs). So Denon decided to use digital only, the Zone2 and for Subwoofer wit separated and much simplier DACs. This may explain your bad results.
 

peng

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@amirm :
I'm absolutely not sure you measured the main AKM DAC at ZONE2 output.
There are 2pcs PCM5102 TI stereo DACs on the board (right up next to AKM) for ZONE2 and Subwoofer outputs. These are responsible for driving the above 2 outputs, even when the main zone and zone2 plays the same music or different. It is necessary use separate DACs there to be able to provide you can also play back separate sources in the MAIN ZONE and ZONE2 same time. According to see a bit closer the main AKM DAC, there are numbers (2-4) of NE5532 opas around there, because of dual-differential DAC configuration needs many opamaps for I/V and filtering, so the number of NE5532s are OK, no other ones for ZONE2. IMHO, because of the ability to drive simultaneosuly the MAIN and ZONE2 there are no separate digital and analog signal path routing/switching (I mean using the main DAC for all zones output - and separately analog routing of signals, different DACs). So Denon decided to use digital only, the Zone2 and for Subwoofer wit separated and much simplier DACs. This may explain your bad results.

Keep in mind the PCM5102's SINAD is only 93 dB. That means the very best the DRM-800H can do it 93 dB SINAD, that's only if there are no other losses in the signal chain of the preamp/DAC.

The AK4458 used in the Denon AVRs have SINAD of 107 dB, that's 14 dB better than the DRA-800H. Even if the DRA receiver is in fact wired in differential from input to output, it cannot make up 14 dB, 3 to 6dB at the most in theory, and I highly doubt it is wired in differential mode anyway. I do expect any receiver in that price range would have the volume control, DAC and OPAs all wired in differential model either. As to why Amir had to measure zone2, I thought he had no choice because this receiver does not have pre out for the main zone.

Edit: Sorry i thought the receiver had the PCM5101/5102, so my comments above don't apply.
 
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ttt

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Keep in mind the PCM5102's SINAD is only 93 dB. That means the very best the DRM-800H can do it 93 dB SINAD, that's only if there are no other losses in the signal chain of the preamp/DAC.

The AK4458 used in the Denon AVRs have SINAD of 107 dB, that's 14 dB better than the DRA-800H. Even if the DRA receiver is in fact wired in differential from input to output, it cannot make up 14 dB, 3 to 6dB at the most in theory, and I highly doubt it is wired in differential mode anyway. I do expect any receiver in that price range would have the volume control, DAC and OPAs all wired in differential model either. As to why Amir had to measure zone2, I thought he had no choice because this receiver does not have pre out for the main zone.
I wouldn't expect Denon lies about the AKM DAC's dual differential setup. It's one of the main selling point of this device, bolded everywhere. The number of NE5532 OPAs around it also an explanation of this. In this setup the S/N, SINAD, distortion would be also improved compared to "normal" setup. Definitely not worsen. This plain old but sound good OPAs have no explanation of this bad output.
If you open the TI's PCM5101 (or 02 - I guess the 01 on PCB) data sheet, the output filter page have very much similarity to the current cut-off filter plots as well, in dB ranges and cutoff as well. The max output of PCM chip is 2V RMS, masured 4V means there should be OPAs between it and output, worsen the 93dB theoretical S/N, even in normal setup. So, in dual diff setup, all AKM analog output is in use, that's the another main reason added 2 PCM5101 extra DACs are added for simulatneous playback on ZONE2 plus the analog subwoofer.

Edit: checked the linearity of PCM 5101/DAC from other measurent, showing the similar 15bit resolution as measured here.


If anyone still doubt what I'm saying about it, I'll open my 800H and messure it from the PCB. Documenting with hi-res photos.

I just wanted to please check again @amirm what you measured and said about this machine despite to DAC(s) inside without knowing what and how is working under the hood.
 
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peng

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I wouldn't expect Denon lies about the AKM DAC's dual differential setup. It's one of the main selling point of this device, bolded everywhere. The number of NE5532 OPAs around it also an explanation of this. In this setup the S/N, SINAD, distortion would be also improved compared to "normal" setup. Definitely not worsen. This plain old but sound good OPAs have no explanation of this bad output.
If you open the TI's PCM5101 (or 02 - I guess the 01 on PCB) data sheet, the output filter page have very much similarity to the current cut-off filter plots as well, in dB ranges and cutoff as well. The max output of PCM chip is 2V RMS, masured 4V means there should be OPAs between it and output, worsen the 93dB theoretical S/N, even in normal setup. So, in dual diff setup, all AKM analog output is in use, that's the another main reason added 2 PCM5101 extra DACs are added for simulatneous playback on ZONE2 plus the analog subwoofer.

Edit: checked the linearity of PCM 5101/DAC from other measurent, showing the similar 15bit resolution as measured here.


If anyone still doubt what I'm saying about it, I'll open my 800H and messure it from the PCB. Documenting with hi-res photos.

I just wanted to please check again @amirm what you measured and said about this machine despite to DAC(s) inside without knowing what and how is working under the hood.

Sorry, my mistake, I thought it had the PCM5101 or 5102. If it is the AK4458 and wired differential then great, too bad they did add preout and up the price a little to cover the added cost.

Post edited, thank you for corrected me.
 

ttt

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Sorry, my mistake, I thought it had the PCM5101 or 5102. If it is the AK4458 and wired differential then great, too bad they did add preout and up the price a little to cover the added cost.

Post edited, thank you for corrected me.
They had no choice if ZONE2 pre-out requires simulatneous (different) playback at the same time. So they just used this 2 "extra" DACs to hande these two "extra" outputs (zone2 and subwoofer) because the dual-differential setup occupied all the 8 I/V output of the AKM chip. The AKM + OPAs are directly driving the poweramp, no available output fron it wired to the back panel. So, I and others would be happy if @amirm corrected the measurement, at least with some notes, that this is not the main DAC, only "a cheap one" to drive ZONE2.
I'd assume to make new measurements based on headphone out, because it's dedicated, the source DAC is the AKM and not going through the power stages. Would be a bit more acceptable.
 
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peng

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They had no choice if ZONE2 pre-out requires simulatneous (different) playback at the same time. So they just used this 2 "extra" DACs to hande these two "extra" outputs (zone2 and subwoofer) because the dual-differential setup occupied all the 8 I/V output of the AKM chip. The AKM + OPAs are directly driving the poweramp, no available output fron it wired to the back panel. So, I and others would be happy if @amirm corrected the measurement, at least with some notes, that this is not the main DAC, only "a cheap one" to drive ZONE2.
I'd assume to make new measurements based on headphone out, because it's dedicated, the source DAC is the AKM and not going through the power stages. Would be a bit more acceptable.

Why do you think the power amp output didn't measure better? In fact much worse than the avrs.
 

ttt

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Why do you think the power amp output didn't measure better? In fact much worse than the avrs.
As I know, in this AVR, the headphone output has dedicated driver, which is usually called "low level" compared to power output, which has affected by the high level design components and architecture.
So saying, the low level dedicated headphone output is a bit closer to a "pure DAC output" what was the original goal.
Sure measurement including the power stages would give the full picture, but the power stages has worse effect on S/N and THD than a low level. Would be see both if possible
 

GiBo61

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I'm no expert so I'm confused and I need some help: the hypothesis is that the ZONE 2 output receives the signal from two PCM5101 extra DACs whose quality is lower compared to the main AK4458 DAC that is busy driving the ZONE 1 power amps. Is this just a speculation or a fact?
Is this also the reason why Denon do not advertise the ZONE 2 output as a real "pre out" (even if it's labelled "pre out"-ZONE 2 on the back of the DRA-800H)?
On the contrary, the (almost identical) twin receiver Marantz NR1200, besides ZONE 2 has a clearly advertised "pre out" output (I guess connected to the internal AK4458 DAC) for a power amplifier for front speakers (as stated in the manual).
Another issue: if the AK4458 DAC performs well in the Denon DRA-800H and is busy feeding the internal power amps, I guess that the not exciting "Amplifier Measurements" in the second part of Amir's review are due to the modest amplifier section. In summary, even if the AK4458 DAC provides a clean audio processing, everything is ruined downstream by the power amplifier stage.
 

peng

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As I know, in this AVR, the headphone output has dedicated driver, which is usually called "low level" compared to power output, which has affected by the high level design components and architecture.
So saying, the low level dedicated headphone output is a bit closer to a "pure DAC output" what was the original goal.
Sure measurement including the power stages would give the full picture, but the power stages has worse effect on S/N and THD than a low level. Would be see both if possible

I understand your point and logic on the DAC part, and of course I also understand that while the preamp/DAC may perform very well, it does not mean the power amps will. However, I hope you understand my logic too, that is:

- If you are right about the DAC being implemented with the very good OPAs NE5532 for "dual differential" then the only reason for the power amp section to measure so much worse than the AVRs such as the AVR-X3600H would probably be because the power amp section of the DRA-800H is so much inferior than that of the AVR-X3600H's.

- So if this assumption is correct (to me the only logical explanation I can think of), then why would Denon even bother with using all of the 8 channels of the AK4458 DAC IC and the required NE5532 to implement the so called (by Denon's marketing) "dual differential" scheme? Now if they had provided the main channel pre outs like the Marantz NR1200 did, then okay I would understand why they would do it. Otherwise it makes no sense, unless we are missing some important facts.

You don't need two 8 channel AK4458 to include pre outs, left + right + sub1 + sub2 count as 4 channels, so you only need 8 channels for differential connections. Even the AVR-X8500H don't have separate DACs for the pre outs, they are just connected in parallel with the inputs to the power amps.

By the way, if you are so sure the DRA-800H uses the OPA NE5532 with the AK4458, can you kindly tell us your source? I tried to search for the information but Denon's or any other websites that mentioned the DRA receiver did not mention anything about the NE5532 OPA.

I am not trying to contradict you in anyway, just want to understand why Denon would use a seemingly very nice preamp/DAC and NE5532 OPAs to drive a not very well measured power amp section, and yet failed to provide the pre outs like its Marantz cousin (NR1200) does, to take advantage of the AK4458 implemented in differential configuration with the NE5532s.

Take a look for your self, and see my point about the AVR amps (using the AVR-X3600H as example) versus the DRA-800H amps:

Not only the AVR-X3600H is a little more powerful into 4 Ohm, it also has almost 14 dB lower in distortions plus noise at the knee point, that's significant!!


index.php
index.php
 

mike7877

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Best you could hope for is 6db better snr from the dual differential. But you never get 6db because of the op amps. Anyway, the 3700 thd+n is -98, so DRA800h could be -104. But that's definitely not the case because I hooked up an external DAC of -102db and it was quieter and subjectively clearer with better bass. This DAC also sounds about the same amount better than the one in the 3700. But the amp in the 3700 is better. My educated guess is in the best case, thd+n of the dual differential DACs in the 800 is the same as the DAC in the 3700. DAC engineers probably didn't optimize the design after seeing the performance of the power amp section. The extra DACs and op amps were already purchased, so they were included to not be wasteful. But just hooked up and not tested cause it didn't matter. I'm joking. Half joking,
 

peng

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Best you could hope for is 6db better snr from the dual differential. But you never get 6db because of the op amps. Anyway, the 3700 thd+n is -98, so DRA800h could be -104. But that's definitely not the case because I hooked up an external DAC of -102db and it was quieter and subjectively clearer with better bass. This DAC also sounds about the same amount better than the one in the 3700. But the amp in the 3700 is better. My educated guess is in the best case, thd+n of the dual differential DACs in the 800 is the same as the DAC in the 3700. DAC engineers probably didn't optimize the design after seeing the performance of the power amp section. The extra DACs and op amps were already purchased, so they were included to not be wasteful. But just hooked up and not tested cause it didn't matter. I'm joking. Half joking,

Interesting, but you may be onto something! It could have been sort of an aborted project for some unknown reason.

May be you should (just joking) send yours to the mod company? I no longer remember the name of that company, or those companies. Jokes aside, it is in theory, probable for the DRA receiver to have 100 to 103/4 dB SINAD if you mod it to include the main zone pre out and measure it.

It seems that the Marantz NR1200 is a non identical twin but has main zone pre out. It most likely has no HDAM so it is possible the NR1200 pre out may measure better than the AVR by a few dB because of the claimed (by Denon) differential DAC implementation, and assuming @ttt is right about the use of the NE5532.

To help solve the mystery, we need someone to send Amir a NR1200, and to acquire the service manuals to confirm if the two have the same preamp/DAC section.:)
 
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ttt

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@peng I stated the NE5532 by a testsite close photos:
Attached the zoomed version from the site photoes. Clearly seen the 6x NE5532.
(off: the NE5532 is NOT a premium chip, it has intorducted in 1979, 42years ago, and quite cheap, anyway sounds acceptable)

Today I decided to open my own device, took a lot of close pics and turned to be very disappointed with Denon :(. They seems just replaced the NE5532 OPAs with cheaper mediocre JRC8080. :( Seems that they sent the "premium" version only for listening testers?
They also changed the 2x PCM5101 DAC to the downgraded version of PCM5100. Please seem my photos below.
Anyway, according to the close look, all of the AKM4458VM DAC output goes to the 3x JRC8080 Dual OPAs, (open here: https://www.akm.com/content/dam/doc.../audio-dac/ak4458vn/ak4458vn-en-datasheet.pdf ) so they seems really use dual-differential DAC configuration, and the DAC is AKM4458.

Didn't measure the PCM5100 output, but following the PCB, it goes toward to the ZONE2 and subwoofer. I'd do it later if needed. I have many other pics about the main PCB and phono, so seems that tey also use AKM chip for Analog inputs digitization.
 

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ttt

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@bloodshoteyed thanks, but after clicking on it see this error, can you help?

System Message
The file appears to have been called from an unauthorized website.

Only links called directly from pages on the Vinyl Engine or HiFi Engine websites can be processed. If you have received this message after following a link from one of these sites, please report the problem in the download section of the forum.
 

bloodshoteyed

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sorry, i forgot that direct links don't work there
you have to register on the site, it's free though: https://www.hifiengine.com
 

bloodshoteyed

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there's the part talked about here:
 

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ttt

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@bloodshoteyed Thanks a lot!
So, my assumption was right, according to the attached block diagram (and the PCB photos), the Zone2 (NETWORK/ Z2) has a dedicated PCM5100A DAC. It is not the one we hear when we listen to the music from the AVR!
Also, the AKM4458 has configured in dual-differential setup.
I was wrong stated the the Subwoofer (SW) using the other PCM5100A, however it's one differentuial output cannel from AKM in mono mode.
The question is: what is the reason soof the second PCM5100A? It called "downmix", what is that?
It'd be nice to revise both the "DAC" measurements and the recommendation / conclusion made on that.
 

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GiBo61

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If I'm not wrong the price of a AKM4458 chip is less than $4 if you buy a stock of 500 units (https://www.digikey.it/product-deta...K4458VN/974-1082-1-ND/5287011?cur=USD&lang=en), while the PCM5100A sells for less than $2 (https://eu.mouser.com/Texas-Instrum...s/PCM5100A-Series/_/N-4gxke?P=1yye73wZ1z0zls6).
I guess that using a more complex DAC like the AKM4458 has also an impact on the layout (and the cost) of the PCB. Anyway, to save a few Dollars Denon has decided to provide a lower quality audio output to ZONE2. At the end this is also resulting in a really bad advertisement for the DRA-800H considering that Amir in his review could only evaluate the PCM5100A output.
This is an important piece of information, at least for me. I was considering to buy a Class D amplifier based on Hypex NC252MP or NC502MP and to connect it to the ZONE 2 output but at this point it would be a complete wast of money.
Denon, I'm really disappointed...
 
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ttt

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I don't beleive Denon added this crappy Volume Chip (NJU72343) after the DAC. 10%THD at -30dB! What about the quiet details?
Another one is the input selector. :( :( Why they just don't digitize evetything with a good ADC and drive the poweramp without these "detail killers"?
Don't understand them...
 

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