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Marantz SR6014 AVR Review

GXAlan

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They do something, in my experience. Measuring an old NA7004 network player, proudly using HDAM,at levels <-1dBFS 2nd harmonic dominates unlike most solid state output stages I imagine. At 0dBFS (ie 2V rms) yes it struggles but most output stages do at full output from what I have measured.

HDAM is also a marketing phrase. It’s unclear how much of the HDAM technology in the hifi line translates to the AVR line.
https://www.dutchaudioclassics.nl/history_of_hdam_module/
 

bigguyca

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HDAM's

The point of the following three paragraphs is that these circuits exist, not to understand their operation:

The HDAM's used by Marantz in AVR's and AVP's are diamond buffer four transistor circuits with (4) resistor current sources. In AVR's the supply voltages are +/- 7V. In the AVP's the supply voltages are +/- 12V.

One output buffer circuit for that supports one RCA output is made up of an HDAM, complementary voltage gain stage (two transistors) and then another HDAM. Feedback is taken from the output of the 2nd HDAM and input to the low impedance node of the first HDAM.

The (-) output leg of the XLR outputs of the AV8805 and AV7705 is made up of (3) HDAM circuits plus the complementary voltage gain stage.

Thoughts

Diamond buffers are well known circuits.

The current sources (or current mirrors) should be implemented with active devices such as transistors. Resistors make mediocre current sources, especially as the circuits become more heavily loaded. Voltage sources attempt to supply whatever current is required to produce a desired voltage. Current sources attempt to supply what ever voltage is required to produce a desired current.

The supply voltages should be +/- 12V minimum.

IC Opamp Alternative

Opamps such as the venerable NE5532 dual opamp would likely provide better performance with +/- 12V supplies. One of these dual opamps would replace two HDAM buffers (4 HDAM's and associated components) and save significant board space as well.

One NE5532 (two opamps) would be required to support the XLR outputs of the AV8805 and AV7705. The NE5532 would replace (5) HDAM's and associated circuitry.

From one distributor chosen at random, NE5532's cost 15 cents in quantity 2,500.

Better opamps are available, but other components (DAC IC's, opamps in the DAC filter circuits, layout) in the AVR's would likely have to be improved before the better opamps would make a significant overall improvement.
 
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amirm

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If (and that is a big if) @amirm has the time now or in the future to run a quick test that will answer some of the most asked questions and narrow down the problems, here are some test files that can be used.
Thanks for creating these. I spent a couple of hours with them and AVR-X4700H but couldn't get anywhere. The multichannel file has a rising high frequency noise floor. The AC-3 version has tons more noise and compression artifacts. Strange because a single channel should have been easy for it to encode.
 

Dj7675

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Yes, but does the unit you own meet the guaranteed output? How do you know? Audioholics likely gets loaners from Denon and other companies.

The point is that the 70% is often stated by posters as a guarantee, not a specification. What would it take to claim that guarantee, if it is a guarantee? If the regular guarantee is 3-years, is the output guarantee 3-years? What are the exact test conditions for verifying the guarantee? What is the remedy if the product is tested and doesn't meet the guarantee? Is some sort of certified lab required to make the measurements?

It all seems like marketing. No one is likely to ever make a claim under that guarantee.
For me, I will know soon enough as I’m sending in the X8500 :) My point is that there are quite a lot of bench tests out there that also show it to be true. Individual units cannot ever be know unless bench tests and that is just the way it is. None of the tests I have seen haven’t failed that number that I have seen and generally exceed it by a good margin. This may not satisfy your needs and in that case you would need to have your unit bench tested. But for me if bench tests are showing it to be true, then that is good enough for me. YMMV.
 

peng

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For me, I will know soon enough as I’m sending in the X8500 :) My point is that there are quite a lot of bench tests out there that also show it to be true. Individual units cannot ever be know unless bench tests and that is just the way it is. None of the tests I have seen haven’t failed that number that I have seen and generally exceed it by a good margin. This may not satisfy your needs and in that case you would need to have your unit bench tested. But for me if bench tests are showing it to be true, then that is good enough for me. YMMV.

I think bigguyca is talking in legal sense, perhaps..
 

SimpleTheater

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I've just been through a selection of service manuals at random:

Sony TA-N9000ES: 1v / 45kohms
Nikko Alpha 440: 1v / impedance not stated
Harman Kardon HK870: 1v / impedance not stated
Onkyo M282: 1v / 50 kohms
Technics SE-900S: 1v / 33 kohms
Nad 2200: 1v / impedance not stated

There are many, many, more....
So nothing under 1 volt. Also you said you use amps at .775 to 1 Volt, are you just randomly looking up ancient amps on the Internet or are these the amps you actually use?
 

Todd74

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I see the volume was set at 82.5 for all tests. Is that the 6014’s volume setting? If so, how are things affected if I’m in the 68-72 range? [it’s a 12x14 room so 72 is really loud].
 
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amirm

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I see the volume was set at 82.5 for all tests. Is that the 6014’s volume setting? If so, how are things affected if I’m in the 68-72 range? [it’s a 12x14 room so 72 is really loud].
It is the indicator on the dial. For lower values see this graph:

index.php


The vertical blue line is at volume 73.5 so you are in the sweet spot with your 68 to 72.
 

Vasr

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Thanks for creating these. I spent a couple of hours with them and AVR-X4700H but couldn't get anywhere. The multichannel file has a rising high frequency noise floor. The AC-3 version has tons more noise and compression artifacts. Strange because a single channel should have been easy for it to encode.

Ugh! It seems the Audacity export as WAV is buggy. It puts a rising volume signal while exporting rising to about -90db at 20khz. Is that what you are seeing?

The spectrum for the original file from RME is cleaner.

1khzSignalSpectrum.PNG


It stays below -120db going all the way out. Is this clean enough for your purposes?

If so, I will find a way to export it differently.

The empty tracks I am able to export by just making them all silent (just empty tracks in Audacity or doing a copy-mix creates the same rising floor). So they will be clean all through as below. Hopefully, this will also show the issue as the AP 8 channel (i.e., silent channels are not treated differently).

ZeroSignalSpectrum.PNG


Just need to find a way to mux them together without introducing noise.

Will be back. Sorry about that.
 
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Todd74

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It is the indicator on the dial. For lower values see this graph:

index.php


The vertical blue line is at volume 73.5 so you are in the sweet spot with your 68 to 72.
Thanks, Amir.
So at that volume level [72], will a 2-channel amp be all that I need (if I’m looking to unlock 11.2 and jettison some heat)? ...... or at that level is an integrated w/ HT bypass a better choice? [4 ohm 87 dB Dynaudio bookshelfs]
 

Dj7675

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I think bigguyca is talking in legal sense, perhaps..
Possibly so. There has been so much negativity and nit picking lately. There have been a lot of complaints against various brands and how they spec their receivers, such as 400W with 1 channel driven... as if that is meaningful in any way. You have a major brand coming out and telling us that if you look at a 2 channel rating, they are designing it to do 70% of that in 5 channels. In many of the tests they are actually hitting 70% in 7 channels. This is actually pretty good on the part of Denon/Marantz and a meaningful number and helps consumers. Maybe guarantee is too strong and has other implications and meaning to people, but to me it means when I shop I can get 70% of the 2 channel rating which is nice to know. And so far, none of the bench tests have shown otherwise which is good enough for me.
 
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amirm

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Ugh! It seems the Audacity export as WAV is buggy. It puts a rising volume signal while exporting rising to about -90db at 20khz. Is that what you are seeing?
Exactly.
 
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amirm

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So at that volume level [72], will a 2-channel amp be all that I need (if I’m looking to unlock 11.2 and jettison some heat)? ...... or at that level is an integrated w/ HT bypass a better choice? [4 ohm 87 dB Dynaudio bookshelfs]
No, just a power amp will do. Just make sure it can produce its maximum power at this voltage level (the "sensitivity" spec for the amp).
 
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amirm

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Will be back. Sorry about that.
No problem. You have been great help. While you are at it, having the files at twice the length would be useful. They are too short at 5 seconds.
 

Todd74

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Amir, regarding the roll-off you mention, do you happen to recall if the MultiEQ was set to “REFERENCE”?

I ask bc the description on the on-screen menu reads, “default calibrated setting with a slight roll off at high frequencies, which is optimized for movies”.

There’s also modes for “OFF”, “FLAT”, and “L/R BYPASS” [which uses the REFERENCE setting but bypasses the fronts].
 
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amirm

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Amir, regarding the roll-off you mention, do you happen to recall if the MultiEQ was set to “REFERENCE”?
I am not using Audyssey. The roll off is clearly due to the slow roll off of the DAC filter. They all do this when using such a slow filter.
 

bigguyca

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AH measured the $4,999 Marantz PM-11S3 that probably has the best HDAM version. At 2 V, it seems about 6 dB better in SINAD than the SR6014, still not nearly as good as the Denon AVRs.

https://www.audioholics.com/amplifier-reviews/marantz-pm-11s3#:~:text=Marantz PM-11S3 Backview&text=The PM-11S3 comes with,detachable two-prong power cord.


The ultimate gain of the HDAM circuitry, even in the optimum form, appears significantly less than that of a good IC opamp. Less gain means less feedback is available and there will be more distortion.

This is similar to the case of many Parasound power amplifiers where the use of JFETS in the input stage, with their reduced transconductance (gain) vs. bi-polar transistors, reduces the overall feedback available. This reduced feedback results in increased distortion.
 

audio_tony

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So nothing under 1 volt. Also you said you use amps at .775 to 1 Volt, are you just randomly looking up ancient amps on the Internet or are these the amps you actually use?

Amps I have owned and in a case of two of them, amps I still do own.

The NAD 2200 btw is 0.775V not 1v - I made a mistake with that one.

My point is - every power amp I have encountered in my servicing career spanning some 40 years, has had an input sensitivity of 0.7v to 1v - I don't remember ever encountering an amp requiring more than 1v for full power.

EDIT: Forgot about a Yamaha MX630 that I once owned - that's 1.1v for full power.
 
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audio_tony

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If those amps are around 100 WPC, 1 V would seem right but for people who want to pair their AVR with 250 to 300 WPC amps, they would want to have 1.5 v or more, in order to have some headroom and the option to go with power amps with gain a little less than 28 to 29 dB.

The NAD 2200 is rated at 140w x2 and as we know from Amir's tests here is closer to 200w RMS - and yet out of all the amps I mentioned, is the most sensitive at 0.7v for full output.

The Nikko is 200+W per channel.
 
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