Denon AVR-X4700 AVR Review (Updated)

[bigguyca]

Just read through this entire thread again. It's clear that the output signal clips at 1.4 volts with any combined use of internal and external amps.

Here is the question I think a lot of people have about the Denon 4700 (and other Denon's as well)
Based on this graph, is it a safe assumption or can it be assumed that with internal amps off the SINAD of the output voltage remains as high or near the curve on this graph with 5 channels connected to an outboard amp? Another way of asking: It appears to me that it's SINAD is 97 @2.3 volts with internal amps off. How would the SINAD of that signal be affected with 5 or 7 channels out? Amir? Others?

- Graph Omitted -

There is no way to turnoff the internal power amplifiers.

OK my bad, but I'd bet you know what I mean. Using the 4700 as a preamp/controller only, with 5 or 7 preamp channels out to an outboard amp what would the SINAD be at 2.3 volts?

The forum has science in the name. Making chains of assumptions that are unlikely to be verified and then betting on what other people think doesn't fit well with science. It isn't even clear what "Safe assumption or can it be assumed," means.

Without measurements or at least schematics of the X4700H, the characteristics of preamp channels that have not been measured is guesswork.

 

[amper42]

The forum has science in the name. Making chains of assumptions that are unlikely to be verified and then betting on what other people think doesn't fit well with science. It isn't even clear what "Safe assumption or can it be assumed," means.

Without measurements or at least schematics of the X4700H, the characteristics of preamp channels that have not been measured is guesswork.

We don't have exact measurements with the Denon 4700 preamp section only and a 2.3V output but, I have used a Purifi based Stereo amp with the Denon 4700 in pre-amp only mode and I'm not detecting distortion from listening tests at low or high volumes. From my view this is a non-issue.

 

[peng]

OK my bad, but I'd bet you know what I mean. Using the 4700 as a preamp/controller only, with 5 or 7 preamp channels out to an outboard amp what would the SINAD be at 2.3 volts?

Educated guess: Yes it should be close to that, say within a few dB.
Reasoning:
-The preamp outputs are always on anyway whether in preamp mode or not.
-Amir has already measured the front L/R using the amp assign feature, under that condition, the other 9 channels were in fact connected to the internal power amps, so in that sense, it's been sort of tested, not just pure guess work that bigguyca might have alluded to.
- It is the same vol IC and DAC IC for all channels, no schematics available for purchase for that model, but this is a "safe" assumption based on circumstantial evidence.

One caveat, my assumption is that you will use it with an external power amp that has input impedance equal to or higher than that of the internal amps. If not, you may still get approximately the same SINAD but it would depend on other assumptions, so the guess would not be an educated guess, or not a "safe" assumption any more.

 

[kevin1969]

I have an external March Audio P252 connected via front pre-outs and in full pre-amp mode it does sound better than if it's in 7ch w/ Zone2 configuration but it's not so much better that I bother to keep it in preamp mode all the time. It does sound good enough that I want to get a second external amp for my Zone2 speakers though because why stop now when I only have another $700 to spend.

 

[peng]

I have an external March Audio P252 connected via front pre-outs and in full pre-amp mode it does sound better than if it's in 7ch w/ Zone2 configuration but it's not so much better that I bother to keep it in preamp mode all the time. It does sound good enough that I want to get a second external amp for my Zone2 speakers though because why stop now when I only have another $700 to spend.

I assume you compared it to 7 Ch+zone2 without the FL/FR disconnected but SINAD won't really deteriorate audibly until pre out voltage gets over 2 V (still 75 dB SINAD at that point), so I wonder what volume were you at when you could hear the difference? Also, which XLR to RCA interconnect are you using? I have to ask because this is the amp I would be interested in, if I eventually want to try a class D Hypex and don't want to buy the DIY kit.

 

[JonfromCB]

I assume you compared it to 7 Ch+zone2 without the FL/FR disconnected but SINAD won't really deteriorate audibly until pre out voltage gets over 2 V (still 75 dB SINAD at that point), so I wonder what volume were you at when you could hear the difference? Also, which XLR to RCA interconnect are you using? I have to ask because this is the amp I would be interested in, if I eventually want to try a class D Hypex and don't want to buy the DIY kit.

Hi Peng, For my understanding, don't you mean the SINAD is still over 95 dB at 2 Volts rather than 75?

 

[peng]

Hi Peng, For my understanding, don't you mean the SINAD is still over 95 dB at 2 Volts rather than 75?

95 dB would be for preamp mode, or for the FL/FR channels that are disconnected via amp assign settings. I said 75 dB because Kevin was talking about 7 ch with z2 so I thought he meant without FL/FR disconnected and also without using preamp mode.

 

[JonfromCB]

Thanks, that helps me understand.

 

[amper42]

I assume you compared it to 7 Ch+zone2 without the FL/FR disconnected but SINAD won't really deteriorate audibly until pre out voltage gets over 2 V (still 75 dB SINAD at that point), so I wonder what volume were you at when you could hear the difference? Also, which XLR to RCA interconnect are you using? I have to ask because this is the amp I would be interested in, if I eventually want to try a class D Hypex and don't want to buy the DIY kit.

@peng - I'm using the Monolith Monoprice 6ft Premier Series XLR Male to RCA cable between the March audio P452 and the Denon 4700. It's found here: https://www.monoprice.com/product?p_id=4777
The same cable would work on the P252. Alan at March Audio ([email protected]) confirmed it has the correct connections.

The P252 has a 26dB voltage gain which is a bit lower than the Denon Receiver amps but it does offer 150W in 8 Ohms. The 2 channel NC252MP from Buckeye amps is $499 vs March Audio version at $795 plus $90 shipping. The Buckeye amp seems a bargain in comparison.
https://www.audiosciencereview.com/...amplifier-builder-line-up-announcement.16835/
email ([email protected]) for orders
Current build ETA for new orders: June 28th

 

[kevin1969]

I assume you compared it to 7 Ch+zone2 without the FL/FR disconnected but SINAD won't really deteriorate audibly until pre out voltage gets over 2 V (still 75 dB SINAD at that point), so I wonder what volume were you at when you could hear the difference? Also, which XLR to RCA interconnect are you using? I have to ask because this is the amp I would be interested in, if I eventually want to try a class D Hypex and don't want to buy the DIY kit.

I'm not sure what 2V is in terms of volume.

 

[MikelLeen]

Apologies in advance if this has been answered. Been reading through this, but it's taking time.
Quick question has the 2 channel only distortion issue described in the initial post of this thread by Amir been resolved?
I'm looking to place an order for this possibly tomorrow.
Thanks

 

[amper42]

Apologies in advance if this has been answered. Been reading through this, but it's taking time.
Quick question has the 2 channel only distortion issue described in the initial post of this thread by Amir been resolved?
I'm looking to place an order for this possibly tomorrow.
Thanks

I'm using analog Denon CD player or Qobuz with UPnP DLNA access for stereo playback with the Denon 4700. No detectable distortion in these configurations. I also use 4K Sony Blu-Ray UBP-X800M2 player for ATMOS and 7.2.4. I'm also not detecting noticeable distortion with these configurations with the Denon 4700. I'm happy with the sound quality.

 

[peng]

I'm not sure what 2V is in terms of volume.

That's fine, I am just wondering what have you been setting the volume to when using the AVR with the external amp P252 vs just using the internal amp (that is, before you have the P252). With such info, I can estimate roughly (very roughly) what the maximum pre out voltage need to be.

 

[kevin1969]

That's fine, I am just wondering what have you been setting the volume to when using the AVR with the external amp P252 vs just using the internal amp (that is, before you have the P252). With such info, I can estimate roughly (very roughly) what the maximum pre out voltage need to be.

I'll try and do some tests today and let you know.

If there's any specific steps or tests you want me to do please feel free to just message me. I'll make sure the levels are the same with an SPL meter and I'll tell you what difference is I can hear between preamp vs front pair off.

 

[peng]

I'll try and do some tests today and let you know.

If there's any specific steps or tests you want me to do please feel free to just message me. I'll make sure the levels are the same with an SPL meter and I'll tell you what difference is I can hear between preamp vs front pair off.

Thank you very much for taking the time to do it. Based on the difference in gain, I would expect the volume setting will need to differ by 2-3 dB for the same sound level, without changing the level trim settings, but obviously if you run Audyssey again after adding the amp, it would increase the level trim settings to offset the lower gain. That's just on paper, your experiment will show the actual difference.

 

[amper42]

Thank you very much for taking the time to do it. Based on the difference in gain, I would expect the volume setting will need to differ by 2-3 dB for the same sound level, without changing the level trim settings, but obviously if you run Audyssey again after adding the amp, it would increase the level trim settings to offset the lower gain. That's just on paper, your experiment will show the actual difference.

Yes, based on my experience Audyssey will level match the NC252MP connected speakers 3 higher than if they were connected to the internal Denon amps.

 

[kevin1969]

Yes, based on my experience Audyssey will level match the NC252MP connected speakers 3 higher than if they were connected to the internal Denon amps.

Ya. I ran a different calibration for the second preset just in case.

 

[bigguyca]

Educated guess: Yes it should be close to that, say within a few dB.
Reasoning:
-The preamp outputs are always on anyway whether in preamp mode or not.
-Amir has already measured the front L/R using the amp assign feature, under that condition, the other 9 channels were in fact connected to the internal power amps, so in that sense, it's been sort of tested, not just pure guess work that bigguyca might have alluded to.
- It is the same vol IC and DAC IC for all channels, no schematics available for purchase for that model, but this is a "safe" assumption based on circumstantial evidence.

One caveat, my assumption is that you will use it with an external power amp that has input impedance equal to or higher than that of the internal amps. If not, you may still get approximately the same SINAD but it would depend on other assumptions, so the guess would not be an educated guess, or not a "safe" assumption any more.

Differences between Denon preamp channels

Haven't seen X4700H details, but X4500H has an opamp buffer on the L and R outputs after volume control. This is a JRC 8080 dual opamp. The other channels don't have this opamp buffer.

Also note that many recent Denon/Marantz AVR's and AVP's bias the opamps in the DAC filter circuit into Class A with a current source off the negative rail. This means that these opamps, which are driving the volume control run in Class A. This should eliminate crossover distortion from these very modest opamps that normally run with very little quiescent bias.

The X3600H uses this Class A opamp bias for the L, C, R. The X4500H doesn't use this Class A bias. The AV7706, SR8015 and X6700H Class A bias the 7-floor channels.

The above are examples of is why guessing the exact characteristics of all of the preamp channels is just that, guessing.


There is also this rather significant change:

https://www.audiosciencereview.com/...akm-ak4458-dac-ic-in-x4700h-and-x6700h.22798/

 

[oupee]

JRC 8080 slew rate 5V/μs that explains a lot

 

[peng]

Differences between Denon preamp channels

Haven't seen X4700H details, but X4500H has an opamp buffer on the L and R outputs after volume control. This is a JRC 8080 dual opamp. The other channels don't have this opamp buffer.

Also note that many recent Denon/Marantz AVR's and AVP's bias the opamps in the DAC filter circuit into Class A with a current source off the negative rail. This means that these opamps, which are driving the volume control run in Class A. This should eliminate crossover distortion from these very modest opamps that normally run with very little quiescent bias.

The X3600H uses this Class A opamp bias for the L, C, R. The X4500H doesn't use this Class A bias. The AV7706, SR8015 and X6700H Class A bias the 7-floor channels.

The above are examples of is why guessing the exact characteristics of all of the preamp channels is just that, guessing.


There is also this rather significant change:

https://www.audiosciencereview.com/...akm-ak4458-dac-ic-in-x4700h-and-x6700h.22798/

Yes, and I was careful with my wording as I have not seen the service manuals of the X4700H, but your mentioning of the DAC change is for the 2021 models is it not? The X4700H was launched many months ago and if I remember right, Denon did say it has the AK4458.

The X6700H and the X3600H's pre out SINAD are within 1 dB iirc.. (with FL/FR disconnected) so my "guess" still stands, that those models, between 2018 and 2020 would be within a few dB, its a case of educated guess vs wild guess. It would be nice for sure if Amir can measure every Marantz that members own, but that's not realistic. So my point is, if ASR has already measured the SR6014 and SR7015, I would rather see Amir measured some other AVR before the SR6015 that can reasonably be expected, or guessed to perform similarly good or bad as the 6014 and 7015.