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Denon AVR-X4700H 2020 AVR Review

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peng

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They actually a very small company in grand scheme of things compared to likes of Sony, Panasonic, Samsung, etc.
But if you compare it, especially if you include Marantz as they obvious share resources now, to Sony and Panasonic's home hifi, HT,(including the pro branch the Denon does have)departments, then they may be comparably big, yes/no?

Thank you very much for keeping us informed on the progress in your communication with Denon.
 

hi_speed

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Since in EU models the tuner is not available, it would have been also interesting to compare NA x4700 and EU x4700.

Maybe they measure the same, maybe not, since they have different internals... who knows.

@amirm if you have the opportunity to speak with Denon engineers could you please ask if they expect NA an EU models to have different performances?

I’m from Italy and I was ready to buy x4700 day one... But since your review I canceled my preorder and many other guys did the same.

I really need a new AVR now, I wanted HDMI 2.1 and 2020 Denon X series was just fitting my needs at the right time, but I don’t want to trade sound quality with one HDMI 2.1...
 

Dj7675

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One difference between the 3xxx and higher series is AL32 processing. It is explained here:
https://denon-uk.custhelp.com/app/a...6/~/alpha-processing-and-what-types-are-there
”AL32 Processing: Denon has further developed its proprietary AL32 Processing, an analog waveform reproduction technology, to support the 192 kHz sampling frequency. AL32 Processing, thoroughly suppresses quantization noise associated with D/A conversion to reproduce the low-level signals with optimum clarity that will bring out all the delicate nuances of the music.”
Possible it could be doing more harm than good?
 
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I don't want to get ahead of the game. :) I have other units coming in including 3700 so I think we will have good coverage ourselves.

Measurements of the Denon X6700H would really be nice. The power amplifier channels in the X6700H are the same as those in the X8500H and Marantz SR8012. These power amplifiers should be the best in the D/M AVR world based on several design features vs. lesser D/M designs. so it would be great to see how they actually measure.
 
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There are actual technical reasons why the performance of the L and R RCA outputs of the X3600H is so good. These outputs have a better design IMO than any other recent model Denon or Marantz AVR or AVP. There is nothing exotic or particularly expensive involved in the design, but it is different. The following explanation is as simple and short as I can make it, but you still likely will have to invest time and thought in understanding it. I’m just a hobbyist so there isn’t anything really challenging here.

There are two major areas of difference between the X3600H L and R RCA outputs and the outputs of other D/M AVR’s and AVP’s.

o Connections to the NJR audio switches and volume controls.

D/M uses the NJR 8-Channel volume control NJU72343.

https://www.njr.com/electronic_device/PDF/NJU72343_E.pdf

Go to page 15 in the datasheet, look at the upper left corner graph, In A1, Out A.

Note that the THD+N at 2V output at 1kHz is about .0005 or -106dB. This is the input used by the L channel directly from the DAC circuitry (DAC IC plus opamp-based filter). The R channel uses a similar input.

The graph also shows performance at other frequencies. The next graph down shows performance at various input levels and attenuations.

D/M uses the NJR 7-in/3-out Analog Switch to route analog signals before and after the volume control.

https://www.mouser.com/datasheet/2/294/NJU72750_E-779912.pdf

In the X3600H the L, R DAC output signals only go through the volume control and not the switches. In all of the other recent, higher-level D/M gear the L and R signals also go through at least one switch and in some cases, two switches.

This website shows measurements from NJR taken when the volume control and switch were first introduced.

http://www.siliconsolutionstream.it/958/

Note that at 2V output the THD+N at 1kHz is .001 or -100dB,

Using these THD+N ratings the best most of the D/M units can do is -100dB vs -106dB in the X3600H.

Noise and distortion accumulate as a signal goes from the output of the DAC IC to the RCA output, so the ultimate performance will of course be worse for either component. The X3600H has a 6dB lead in this horse race. Note that the rated performance of the basic DAC IC in any of these D/M products is at least -106dB, so better DAC IC’s make little to no difference.

o Design of DAC opamp filter circuitry

For a reason only known the Denon the X3600H has the best DAC filter circuitry for the L, R, and C channels of any of their upper level AVR’s or AVP’s.

The DAC filter circuitry contains an opamp in a differential amplifier configuration that combines the + and – signal from each channel from the DAC IC. This circuit functions to boost the signal level from 1V (-1V) on each leg to 2V, remove common mode noise, and remove remaining noise from the DAC process. The design of this circuit is fundamentally (exactly) the same on all D/M units. It uses an NJR 8080 opamp of very modest quality, and associated resistors and capacitors.

o Resistors

Most Denon AVR’s appear to use 5% tolerance, thick film surface mount resistors. Thick film resistors have excess noise and distortion above the normal Johnson noise in a resistor. The tolerance of the resistors affects how well the common mode noise is removed.

- Except -

The X3600H which uses 1% tolerance, thin-film surface mount resistors in ALL of the DAC filters for all channels. This type of resistor now costs little more than thick film resistors and has no excess noise or distortion. The higher precision means better matching between resistors which improves the reduction of common mode noise. Marantz has adopted these resistors on some of its most recent models including the AV7705 for example. At current prices there is little added cost to use these resistors. Better resistors make an improvement, everything helps.

o Power supply filtering

The L, R and Center channel DAC filters have an extra filter on the negative supply rail for the opamps. This will reduce the amount of noise that is transferred from the opamp to the audio signal. No other D/M AVR or AVP that I’ve seen has these filters. The rail voltages for the opamps are (+,-) 8V vs. 7V in other D/M gear. This increase in voltage is to account for the voltage loss in the DAC negative supply rail filter, but provides slightly better performance for all the opamps in the X3600H, and the signal switches and volume controls which also use this supply. Another contributor to better performance.

For interest: Similar filters are used in the power amplifier channels for the SR8012, X8600H and X6500H for (-) rail of the input and voltage gain stages.

Summary:

The L and R RCA outputs of the AVR-X3600H, when disconnected from a power amplifier channel, measure better than those in other D/M products. There appear special features in the design of the X3600H that make the X3600H design different from the design of other D/M units These differences in design would appear to lead to better measured performance and may account for the superior performance of the X3600H.

The added cost of the special features in the X3600H is likely minimal. It is unclear why Denon (or D/M) chose to use a superior design for the L and R channels of the X3600H, a relatively modest product in the Denon lineup.


Note: If this post appears familiar, I previously posted this piece on the AVSForum.
 

Dj7675

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There are actual technical reasons why the performance of the L and R RCA outputs of the X3600H is so good. These outputs have a better design IMO than any other recent model Denon or Marantz AVR or AVP. There is nothing exotic or particularly expensive involved in the design, but it is different. The following explanation is as simple and short as I can make it, but you still likely will have to invest time and thought in understanding it. I’m just a hobbyist so there isn’t anything really challenging here.

There are two major areas of difference between the X3600H L and R RCA outputs and the outputs of other D/M AVR’s and AVP’s.

o Connections to the NJR audio switches and volume controls.

D/M uses the NJR 8-Channel volume control NJU72343.

https://www.njr.com/electronic_device/PDF/NJU72343_E.pdf

Go to page 15 in the datasheet, look at the upper left corner graph, In A1, Out A.

Note that the THD+N at 2V output at 1kHz is about .0005 or -106dB. This is the input used by the L channel directly from the DAC circuitry (DAC IC plus opamp-based filter). The R channel uses a similar input.

The graph also shows performance at other frequencies. The next graph down shows performance at various input levels and attenuations.

D/M uses the NJR 7-in/3-out Analog Switch to route analog signals before and after the volume control.

https://www.mouser.com/datasheet/2/294/NJU72750_E-779912.pdf

In the X3600H the L, R DAC output signals only go through the volume control and not the switches. In all of the other recent, higher-level D/M gear the L and R signals also go through at least one switch and in some cases, two switches.

This website shows measurements from NJR taken when the volume control and switch were first introduced.

http://www.siliconsolutionstream.it/958/

Note that at 2V output the THD+N at 1kHz is .001 or -100dB,

Using these THD+N ratings the best most of the D/M units can do is -100dB vs -106dB in the X3600H.

Noise and distortion accumulate as a signal goes from the output of the DAC IC to the RCA output, so the ultimate performance will of course be worse for either component. The X3600H has a 6dB lead in this horse race. Note that the rated performance of the basic DAC IC in any of these D/M products is at least -106dB, so better DAC IC’s make little to no difference.

o Design of DAC opamp filter circuitry

For a reason only known the Denon the X3600H has the best DAC filter circuitry for the L, R, and C channels of any of their upper level AVR’s or AVP’s.

The DAC filter circuitry contains an opamp in a differential amplifier configuration that combines the + and – signal from each channel from the DAC IC. This circuit functions to boost the signal level from 1V (-1V) on each leg to 2V, remove common mode noise, and remove remaining noise from the DAC process. The design of this circuit is fundamentally (exactly) the same on all D/M units. It uses an NJR 8080 opamp of very modest quality, and associated resistors and capacitors.

o Resistors

Most Denon AVR’s appear to use 5% tolerance, thick film surface mount resistors. Thick film resistors have excess noise and distortion above the normal Johnson noise in a resistor. The tolerance of the resistors affects how well the common mode noise is removed.

- Except -

The X3600H which uses 1% tolerance, thin-film surface mount resistors in ALL of the DAC filters for all channels. This type of resistor now costs little more than thick film resistors and has no excess noise or distortion. The higher precision means better matching between resistors which improves the reduction of common mode noise. Marantz has adopted these resistors on some of its most recent models including the AV7705 for example. At current prices there is little added cost to use these resistors. Better resistors make an improvement, everything helps.

o Power supply filtering

The L, R and Center channel DAC filters have an extra filter on the negative supply rail for the opamps. This will reduce the amount of noise that is transferred from the opamp to the audio signal. No other D/M AVR or AVP that I’ve seen has these filters. The rail voltages for the opamps are (+,-) 8V vs. 7V in other D/M gear. This increase in voltage is to account for the voltage loss in the DAC negative supply rail filter, but provides slightly better performance for all the opamps in the X3600H, and the signal switches and volume controls which also use this supply. Another contributor to better performance.

For interest: Similar filters are used in the power amplifier channels for the SR8012, X8600H and X6500H for (-) rail of the input and voltage gain stages.

Summary:

The L and R RCA outputs of the AVR-X3600H, when disconnected from a power amplifier channel, measure better than those in other D/M products. There appear special features in the design of the X3600H that make the X3600H design different from the design of other D/M units These differences in design would appear to lead to better measured performance and may account for the superior performance of the X3600H.

The added cost of the special features in the X3600H is likely minimal. It is unclear why Denon (or D/M) chose to use a superior design for the L and R channels of the X3600H, a relatively modest product in the Denon lineup.


Note: If this post appears familiar, I previously posted this piece on the AVSForum.
Does the 100 max sinad likely apply to the x8500 as well? Wondering if you have seen the schematics for the x8500 to compare to the x3600.
 

peng

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There are actual technical reasons why the performance of the L and R RCA outputs of the X3600H is so good. These outputs have a better design IMO than any other recent model Denon or Marantz AVR or AVP. There is nothing exotic or particularly expensive involved in the design, but it is different. The following explanation is as simple and short as I can make it, but you still likely will have to invest time and thought in understanding it. I’m just a hobbyist so there isn’t anything really challenging here.

There are two major areas of difference between the X3600H L and R RCA outputs and the outputs of other D/M AVR’s and AVP’s.

o Connections to the NJR audio switches and volume controls.

D/M uses the NJR 8-Channel volume control NJU72343.

https://www.njr.com/electronic_device/PDF/NJU72343_E.pdf

Go to page 15 in the datasheet, look at the upper left corner graph, In A1, Out A.

Note that the THD+N at 2V output at 1kHz is about .0005 or -106dB. This is the input used by the L channel directly from the DAC circuitry (DAC IC plus opamp-based filter). The R channel uses a similar input.

The graph also shows performance at other frequencies. The next graph down shows performance at various input levels and attenuations.

D/M uses the NJR 7-in/3-out Analog Switch to route analog signals before and after the volume control.

https://www.mouser.com/datasheet/2/294/NJU72750_E-779912.pdf

In the X3600H the L, R DAC output signals only go through the volume control and not the switches. In all of the other recent, higher-level D/M gear the L and R signals also go through at least one switch and in some cases, two switches.

This website shows measurements from NJR taken when the volume control and switch were first introduced.

http://www.siliconsolutionstream.it/958/

Note that at 2V output the THD+N at 1kHz is .001 or -100dB,

Using these THD+N ratings the best most of the D/M units can do is -100dB vs -106dB in the X3600H.

Noise and distortion accumulate as a signal goes from the output of the DAC IC to the RCA output, so the ultimate performance will of course be worse for either component. The X3600H has a 6dB lead in this horse race. Note that the rated performance of the basic DAC IC in any of these D/M products is at least -106dB, so better DAC IC’s make little to no difference.

o Design of DAC opamp filter circuitry

For a reason only known the Denon the X3600H has the best DAC filter circuitry for the L, R, and C channels of any of their upper level AVR’s or AVP’s.

The DAC filter circuitry contains an opamp in a differential amplifier configuration that combines the + and – signal from each channel from the DAC IC. This circuit functions to boost the signal level from 1V (-1V) on each leg to 2V, remove common mode noise, and remove remaining noise from the DAC process. The design of this circuit is fundamentally (exactly) the same on all D/M units. It uses an NJR 8080 opamp of very modest quality, and associated resistors and capacitors.

o Resistors

Most Denon AVR’s appear to use 5% tolerance, thick film surface mount resistors. Thick film resistors have excess noise and distortion above the normal Johnson noise in a resistor. The tolerance of the resistors affects how well the common mode noise is removed.

- Except -

The X3600H which uses 1% tolerance, thin-film surface mount resistors in ALL of the DAC filters for all channels. This type of resistor now costs little more than thick film resistors and has no excess noise or distortion. The higher precision means better matching between resistors which improves the reduction of common mode noise. Marantz has adopted these resistors on some of its most recent models including the AV7705 for example. At current prices there is little added cost to use these resistors. Better resistors make an improvement, everything helps.

o Power supply filtering

The L, R and Center channel DAC filters have an extra filter on the negative supply rail for the opamps. This will reduce the amount of noise that is transferred from the opamp to the audio signal. No other D/M AVR or AVP that I’ve seen has these filters. The rail voltages for the opamps are (+,-) 8V vs. 7V in other D/M gear. This increase in voltage is to account for the voltage loss in the DAC negative supply rail filter, but provides slightly better performance for all the opamps in the X3600H, and the signal switches and volume controls which also use this supply. Another contributor to better performance.

For interest: Similar filters are used in the power amplifier channels for the SR8012, X8600H and X6500H for (-) rail of the input and voltage gain stages.

Summary:

The L and R RCA outputs of the AVR-X3600H, when disconnected from a power amplifier channel, measure better than those in other D/M products. There appear special features in the design of the X3600H that make the X3600H design different from the design of other D/M units These differences in design would appear to lead to better measured performance and may account for the superior performance of the X3600H.

The added cost of the special features in the X3600H is likely minimal. It is unclear why Denon (or D/M) chose to use a superior design for the L and R channels of the X3600H, a relatively modest product in the Denon lineup.


Note: If this post appears familiar, I previously posted this piece on the AVSForum.
You are referring to the left, right and center channels so are you saying that the differences, i.e. the switches in the signal path, 1% tolerance resistors, differential connections of the filter circuitry only apply to the LCR channels but not the other 8 (surround/height/Atmos) channels?

And how about analog input, in that case the benefits of the dac filters would be irrelevant but how about the NJU72750AV switches, would the 2020 models have an extra switch in the path even in the analog input (assume direct mode is used) path?

Edit: One more question, the only difference in the signal path between the AVR-X4500H/X6500H and the X4700H/X6700H regarding the use of the switches is that the 4700/6700 is has to provide the all channel preamp mode so more switches are probably needed to do the disconnections to the power amps. So if my logic is right on this, why wouldn't Denon skip one switch for the X4500/6500H like they did with the X3600H and save some money?

Thank you very much for such valuable information (at least for us curious engineers).:D
 
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Does the 100 max sinad likely apply to the x8500 as well? Wondering if you have seen the schematics for the x8500 to compare to the x3600.
It would be best to have measurements of all these products. The X3600H is different enough in enough areas to make a case why the differences exist. That said...

Like most higher-level D/M gear all the L and R channels in the X8500H (and Marantz AV8805, see below) go through a switch and then the volume control. In the X8500H, from the volume control the output divides, one leg goes directly to the RCA outputs with no switch in the middle. The other leg goes to another set of switches that controls routing of channels among the power amplifiers.

In the Marantz AV8805 the output from the volume control goes to a set of switches that control routing of the small signals among the small signal outputs. Between the switches and the outputs are the HDAM 0dB gain, likely low distortion, output buffers.

Net the X8500H as one switch and a volume control on the way to its RCA outputs, but two switches on way to the power amplifiers. The AV8805 has two switches and a volume control. These differences seem to reveal little about any ultimate performance differences between the two.

You can make you own decision as to whether the small signal performance of the X8500H is similar to that of the Marantz AV8805 AVP. Measurements of the AV8805 are available on this forum. The X8500H has only unbalanced (RCA) outputs so dividing the balanced voltage outputs shown in the AV8805 measurements by two seems reasonable.

The AV8805 does have the HDAM output buffers. The gain of these buffers is 0dB and the distortion should be low so they should have no negative effect on the performance of the AV8805. That said, there is added noise of some unknow level in the AV8805 measurements due to extensive cabling, and the noise produced by any electronics and resistors.

The benefit of the HDAM's is that they are better voltage sources than the volume control outputs used directly. In measurements the Audio Precision equipment, as likely setup by Amir, provides a high impedance, easy to drive load, so the HDAM's likely provide no benefit.
 

GXAlan

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The benefit of the HDAM's is that they are better voltage sources than the volume control outputs used directly. In measurements the Audio Precision equipment, as likely setup by Amir, provides a high impedance, easy to drive load, so the HDAM's likely provide no benefit.
In your estimation, how low of an impedance would an amp need to have before you started to see some benefit from the HDAM?
 

peng

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In your estimation, how low of an impedance would an amp need to have before you started to see some benefit from the HDAM?
bigguy.ca would likely have a different opinion. To me, I would say 10 kOhm is a safe bet, for pre-out voltage up to 2 V in preamp mode. That should give you a good margin based on the graph V vs Ohms. Practically speaking I see no benefits from the HDAM. HTFI and ASR both have soon the AV8805 did not produce better SINAD than the AVR-X3600H or even the X4700H (Toslink and analog input) at the 2 V level, i.e. 4 V for the 8805 because of the XLR/unbalanced output.

At above 4 V, i.e. 8 V XLR then HDAM may help, but by then you will be so close to the 4.2 V limit of the chip so there is no practical value there either.

HDAM in Marantz AVRs/AVPs, like Denon's AL32 and DDSC features on the digital side are more marketing hypes/fluff that don't mean a lot for practical use. HDAM, should at least help, in the PM series integrated amps, on paper anyway.

https://www.njr.com/electronic_device/PDF/NJU72343_E.pdf

See page 14

1593448711765.png
 
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(1) You are referring to the left, right and center channels so are you saying that the differences, i.e. the switches in the signal path, 1% tolerance resistors, differential connections of the filter circuitry only apply to the LCR channels but not the other 8 (surround/height/Atmos) channels?

(2) And how about analog input, in that case the benefits of the dac filters would be irrelevant but how about the NJU72750AV switches, would the 2020 models have an extra switch in the path even in the analog input (assume direct mode is used) path?

Edit: One more question, the only difference in the signal path between the AVR-X4500H/X6500H and the X4700H/X6700H regarding the use of the switches is that the 4700/6700 is has to provide the all channel preamp mode so more switches are probably needed to do the disconnections to the power amps. So if my logic is right on this, (3) why wouldn't Denon skip one switch for the X4500/6500H like they did with the X3600H and save some money?

Thank you very much for such valuable information (at least for us curious engineers).:D

(1) The improved DAC output circuitry is used only for the L,C,R channels, not the remaining channels.

(2) The switches are used for the L and R channels for all signals, that is DAC outputs and the various analog inputs. The remaining channels don't go through the switches. The L and R channels are the ones affected by the switches. The switches are required to route the various L and R RCA inputs to the L and R outputs. This signal routing is due to the large number of L and R RCA inputs. Supporting analog audio inputs in AVR's/AVP's adds to cost and complexity.

Clearly there are other ways to handle the L and R channels, such as adding more 8-channel volume controls, but that will likely add to cost and there may be many other factors of which we aren't aware.

(3) We can just hope that in the future Denon will pay more attention to many of these factors. Keep in mind that the capability of disconnecting the power amplifier channels from the RCA outputs is important at any signal level, not just at clipping of the power amplifier channels.

The input impedance of the power amplifier channels is about 33k ohms even if a speaker isn't connected to the channel. This impedance is in parallel with the input impedance of the device connected to the RCA. When tested with AP gear with say a 100k ohm input impedance the effect impedance is about 22k ohms. Connect to a 33k ohms input and the impedance drops to 16.5k ohms, 20k ohms input drops to 12.5k ohms and 10k ohms to 7.7k ohms.

How low is too low? How low significantly affects performance? One way to view the question is that output impedance of the RCA's from the AV8805 that have output buffers is about 320 ohms. If we use 10x a figure of merit that makes an input impedance of at least 3.2k ohms a reasonable number. Any of the above scenarios work.

Evaluating the 8-channel volume control seems more complex since the output impedance may vary with the attenuation setting and internal opamps in the volume control aren't very robust. The specifications for the NJU72343 are taken at 47k ohms, but lower than that must be acceptable or the control would be unusable in most situations. Looking at the datasheet:

www.njr.com/electronic_device/PDF/NJU72343_E.pdf

On page 14, looking at the graph: Output Voltage vs Load Resistance

With 4.2V in, the output voltage falls as the control is unable to supply enough current into lower frequencies to support 4.2V. Of course 4.2V isn't often required. Pick your spot on the curve and you have your answer.

For another data point: Yamaha uses the Rohm BD34701ks2 or similar, 8-channel volume control in some of its AVR's/AVP's.

https://www.mouser.com/datasheet/2/348/bd34701ks2-e-1807077.pdf

The BD34703ks2 has a somewhat more robust current output. The distortion/noise specifications seem similar. On page 27 of the datasheet the minimum load impedance is given as 10k ohms. There is a graph on the same page showing output vs. load resistance at 1% THD+N. While this may not be a valid way to view all this, if the minimum for the Rohm unit is 10k ohms the the minimum for the NJR unit is likely higher. The actual THD+N driving these minimum impedances at various output levels is not specified.

A straight forward way to render this question mute would be to follow the volume control outputs with opamp buffers. These opamps would serve the same function as the HDAM's in the AV8805. Lots of opamps and supporting passives components would add cost and heat to a unit. Really excellent opamps, higher rail voltages, and circuit boards with more layers would add even more cost and heat. Frankly I doubt people want to pay for them, Don't hold your breath. Yamaha does use opamp buffers in some of their higher end AVR's/AVP's for some channels.

o While it is interesting to speculate on the effects of these components, and dream about all sorts of enhancements, measurements of the products provide the bottom line.
 
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Bigguyca, do you speak about opamp buffers for the pre-amp outputs (RCA)?
I hope that Denon has them on the x4700h.
The only output buffers connected to the output of volume control channels in D/M AVR's/AVP's that I've seen are the HDAM output buffers in the Marantz AVR's/AVP's. Denon doesn't have output buffers after the volume control channels.

The Marantz HDAM's IMO are a suboptimum solution vs. using good IC opamps, but that is another subject. The HDAM's do however "sound good" from a marketing standpoint.
 

peng

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www.njr.com/electronic_device/PDF/NJU72343_E.pdf

o While it is interesting to speculate on the effects of these components, and dream about all sorts of enhancements, measurements of the products provide the bottom line.
Agreed, but that's the trouble though, from the review/measurements of the AV7705, there was no indication that the HDAM benefits it output.
It managed only 74.55 dB SINAD at 4 V, XLR, that's equivalent to 2 V RCA. So it couldn't even match the X4700's 75.73 dB at 2 V RCA.
Yes when connected to an external power amp with input impedance 10,000 ohm things can change, but the fact that the 7705's SINAD drop so much going from 2.4 V to 4 V XLR, means it could also do worse if connected to a load of 10,000 ohms
The graph on page 14 would indicate that the NJU72343 without an OPA buffer stage to follow can handle 10,000 ohm without any trouble, at least at up to 2 V.

Hometheaterhifi.com also highlighted the fact that the replacing the LSI chip with the MSI (NJU7343) did not result in better THD+N. Dr. Rich actually alluded (very subtly) to the possibility of the HDAM adding distortions/noise that offset the better performance of the MSI vol chip.
 
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Agreed, but that's the trouble though, (2) from the review/measurements of the AV7705, there was no indication that the HDAM benefits it output.
(3) It managed only 74.55 dB SINAD at 4 V, XLR, that's equivalent to 2 V RCA. So it couldn't even match the X4700's 75.73 dB at 2 V RCA.
Yes when connected to an external power amp with input impedance 10,000 ohm things can change, but the fact that the 7705's SINAD drop so much going from 2.4 V to 4 V XLR, means it could also do worse if connected to a load of 10,000 ohms

(1) The graph on page 14 would indicate that the NJU72343 without an OPA buffer stage to follow can handle 10,000 ohm without any trouble, at least at up to 2 V.

Hometheaterhifi.com also highlighted the fact that the replacing the LSI chip with the MSI (NJU7343) did not result in better THD+N. Dr. Rich actually alluded (very subtly) to the possibility of the HDAM adding distortions/noise that offset the better performance of the MSI vol chip.
(1) The curve on the graph on page 14 likely shows output at 1% distortion. Just being within the curve doesn't guarantee excellent performance, it just avoids horrible performance. The curve for the Rohm part is better than the NJR part and it is at 1%. Either NJR provides to customers, or customers like D/M develop further curves for say .01% and .001% distortion, both at 1k Hz and 20 kHz. Also remember that the distortion and noise for the whole unit is some hard to predict "sum" of the performance of the individual parts. Certainly simulation in an ECAD tool would help, but ultimately building a prototype is required to determine actual performance since physical layout of cables and boards is important.

(2) If the HDAM's provide a benefit it will be in driving low impedances. As the previous post noted, AP equipment for these measurements is usually set for a high input impedance so it would unlikely that any output buffer would make a difference since the AP equipment represents a very easy load.

(3) My put on the AV7705 (and the AV8805) is that its measurement issues have more to do with its physical layout than circuit design.

Look at an AV7705 with the cover off and you'll see a huge number of cables running from the main horizontal boards in the back of the unit to the HDAM board and returning. Each of these cables acts as an antenna to collect noise. The cables running from the HDAM balanced output run next to, or over the power supply for the AV7705, which is a very electrically noisy environment. The power supply board uses a single layer board implementation in some locations where physical wires are used as jumpers instead of circuit board traces. The distance between the wire and a ground on the board makes a loop to radiate noise. Signals on these jumpers attract noise is the same manner. Layout issues are likely the chief problems with the HDAM circuits, even if their basic performance is good. (which is unknown).

A layout with the DAC IC's, filters, volume controls and switches, opamp buffers and XLR outputs on one board at the bottom of the unit would be far better. This is the layout in the Emotiva and Monoprice units for example and they obtain better, although clearly not optimum performance. This layout would allow the power supply components to be relocated toward the front of the AV7705. Electric and magnetic fields at the frequencies involved fall off at between the square and cube of distance so a little space would help greatly.

More layout examples:

You'll also note that the cable from the front HDMI input runs very close to the connection from the SMPS to the digital board along the SMPS side of the unit. It's possible that signals transfer to the HDMI ground and then to the main HDMI switch from the SMPS connection.

Likely depending on the individual who assembled the AV7705, the two sets of cables from the power transformer to the input of the low voltage linear power supplies may run close to the diodes and capacitors for the HDAM power supply, and to the cables from the power transformer to this power supply. These components are likely to radiate multiples of 120Hz. The cables from the power transformer to the power supply for the HDAM are sometimes in a loop. This extra turn likely squares the intensity of the magnetic field from these cables that contain currents at multiples of 120Hz.

The 120V input to the SMPS and the 120V take off for the power transformer are naturally in the same location. The SMPS is controlled by a chip that intentionally jitters the switching frequency. This reduces peaks in the conducted emissions, but there is still lots of energy present. The filter on the input side of the SMPS is OK, but could be better. These two factors may put high frequencies from the SMPS on the 120V supply to the power transformer. The 120V supply to the power transformer also runs close to the SMPS board for a distance before running down its side and then over to the power transformer. Any of the induced noise that wonders around in the unit and gets into clock circuits can cause less than optimum HDMI issues.

These sorts of physical layout issues are common to AVR's/AVP's and are one of the main reasons why the performance of these products is often less than the circuit design and component selection would indicate. Some of these issues vary from specimen to specimen depending how the assembler runs cables.

The above may seem a bit, or way overboard, but they are included in an attempt to explain some of the inherent tradeoffs from squeezing a lot of components and wires into a small area without use of a better physical layout and circuit boards with more than two layers. Some of the items above may make a difference, some may not. There are surely other layout issues that were missed. All of this is why measurements are so important to define the actual performance of an AVR/AVP.
 
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My 10 years old Yamaha (RX-A700) has one op-amplifier driving each RCA pre-out.
I will have to verify that on the next AVR that I will buy (3700h?).

Correction: the volume circuit IC has 2 discrete outputs, one that drives the pre-out RCA and another that drives the power amplifier section.
 
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Has anyone measured the input to output latency to expect on the Denon’s in Direct or Direct Pure mode?

I was considering getting an X4700H (until I read this!), maybe an X6700H now?

I’d considering whether I could use Zone 2 to drive a DJ setup.
 
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amirm

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So Phil Jones from Denon brags about audio performance here:
(there are three slides). I don't see things changing anytime soon.
:( These results are still being discussed among us. Disappointed to see their marketing department already running with them.

Anyway, if I were him I would not brag about two digital audio standards -- Toslink and HDMI -- producing 3 dB different results in SINAD. They better be equal in performance since the same downstream DAC is used for both. And the same test signal is used for both. Jitter can vary (although it shouldn't). But not noise and distortion.

Anyway, the Toslink results match mine and that is one of the areas of agreement.
 
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