Marantz SR6014 AVR Review

[peng]

I can't agree with that.

The volume/voltage of the pre-outs sets indeed a voltage upper limit. No dynamic of burst coming from the source would surpass the voltage selected through the volume control. And the power amp (usually fixed) gain multiplies that voltage.

Those peak watts are mainly related to the power-amp ability to drive low impedance speakers in specific frequency ranges (the lower ones in most cases) which eventually could even go below 4ohms, even 2ohms. Going from 4ohm to 2ohms will demand to the amplifier double watts for the same voltage level.

NAD 2200 specs say:

So the IHF Dynamic rating is 400 W into 8 ohm

Now do you math and you will see that for the power amp to output 400 W into 8 ohm (8 ohm, by the way is not "low impedance), you will need
about 1.42 V if, and only if, you want to take full advantage of the much higher IHF rating.

Watts = ( Volts * Volts ) / Ohms

So to make use of the full/burst potential watts of a moderate to high gain amplifier, even when listening at high domestic SPL most setups certainly doesn't need more than 1.2v. That would depend on the power amp gain and speakers impedance and sensivity. Obviously very low sensivity speakers (less than 87dbs) could demand to the user to raise the volume level to reach the same SPL than with other ones.

I can't agree with that.

As I mentioned above, you will need >1.4 V, and is quite a bit higher than 1.2 V, to achieve 400 W into 8 ohms based on the NAD 2200's 32 dB gain, and I think you would agree that 32 dB gain is relatively high for power amps. If you don't want to use 32 dB gain for your calculations, you can get the same result based on the spec sheet's given 0.7 V for the rated output of 100 W into 8 ohms.

If you do the math, and prove me wrong then I will take the eggs.

 

[Gedeon]

It isn't about math it's about the difference between IHF and RMS. No need for those 1.4v if sensivity is rated at 1.0.

But anyway you seem more focused in trying to "win" internet discussions than in learning how these things work.

Good luck.

 

[peng]

Yes and no:

• No regarding distortion, if without this buffer the preceeding stage would distort more due to the higher load.

Fully agreed, the key word is "if", that's why I suggested that Amir do his measurements with a 10 kOhm, or even lower, such as 8 kOhm load resistor. That's too time consuming for him so he used the 600 ohm that is build in with the AP. From the graph he provided using the 600 ohm test load, I did my calculations and projected that the Denon models, without the HDAM buffer would not have more distortions that the Marantz that has the buffer. Without using a more realistic test load, that can't be 100% sure. I am not the only one speculating this, Dr. Rich of hometheaterhifi.com sort of mentioned the same possibility too. It looks like Amir also feels the same, but still, no solid proof without more tests.

The only thing is, in the 600 ohm test load case, Amir found that distortions did not seem to suffer, only the voltage output dropped, but that's expected when loading is so severe. That could be just a little tell tale sign, in the absence of measuring with a 6 to 10 kOhm test load to simulate a realistic higher load you alluded to.

You an see that the Denon was still at a respectable SINAD of 100 dB at 0.5 V, whereas the Marantz was 5 dB lower at 95 dB:
I find it very interesting, comparing those two graphs side by side.

 

[peng]

It isn't about math it's about the difference between IHF and RMS. No need for those 1.4v if sensivity is rated at 1.0.

But anyway you seem more focused in trying to "win" internet discussions than in learning how these things work.

Good luck.

That's not about winning at all, please.. I would be happier to lose and learning something, than to "win" in proving someone is wrong, seriously and sincerely. Obviously I failed to express my points, will need to learn and work on that for sure.

 

[RichB]

That's not about winning at all, please.. I would be happier to lose and learning something, than to "win" in proving someone is wrong, seriously and sincerely. Obviously I failed to express my points, will need to learn and work on that for sure.

ASR has shown that power amplifiers can have better SINAD than AVR/AVPs.
Do we know the effect of preamplifier distortion combined with amplifier distortion?

- Rich

 

[peng]

ASR has shown that power amplifiers can have better SINAD than AVR/AVPs.
Do we know the effect of preamplifier distortion combined with amplifier distortion?

- Rich

I don't, will try to do some research on the internet to see if they are good papers, articles out there. If you know of some, please do share.

 

[GXAlan]

+1.

But last time I looked at these units from Marantz, they seemed intentionally crippled to keep prices low and not compete with SR lines. They all seemed to have much lower component grade selection from connectors to power supplies to electronic components. Under-powered amps. So, I am not sure how they would actually measure. Marantz was the only one that gave L and R pre-outs in addition to sub out if you wanted a more powerful amp for the mains. Rest were sub out only. So I gave up on them.

Things may have changed recently. Haven't looked.

They are actually pretty pricey. They only have pre out for the front channel but the NR1710 is $750 and the NR1200 is $600.

They are crippled with Audyssey XT instead of XT32 but at least audio.pl, the performance is pretty respectable within the limits of the power. With high efficiency speakers or a small room, they seem pretty reasonable as long as you can stay under 30W or so.

83 dB at 1W,
https://audio.com.pl/testy/kino-domowe/amplitunery-av/3147-marantz-nr1510


Translate to English. Subjectively, this person thought it was pleasant — their other gear is Luxman and Accuphase. In Japan, listening rooms are small and typical volumes may not be as high.
https://www.phileweb.com/sp/review/article/201911/15/3627.html

 

[Gedeon]

That's not about winning at all, please.. I would be happier to lose and learning something, than to "win" in proving someone is wrong, seriously and sincerely. Obviously I failed to express my points, will need to learn and work on that for sure.

As you wish...

With 1volt and 32db gain

32db gain -> 39.8 voltage ratio -> 39.8volts (if feed with 1volt)

Driving a 2ohms impedance speaker Watts - > (39.8v * 39.8v) / 2ohms -> 792watts

You had all these numbers. You only need 1v in order to make a power amp with 32db gain to try to deliver 792watts paired with a 2ohms speakers.

 

[bigguyca]

ASR has shown that power amplifiers can have better SINAD than AVR/AVPs.
Do we know the effect of preamplifier distortion combined with amplifier distortion?

- Rich

Generally speaking:

Power amplifiers normally have a better S/N than preamps because they are handling high level signals.

Preamps normally have lower distortion than power amplifiers (ignore the AHB2) because they are handling small signals that require a lower voltage and less current to produce.

 

[bigguyca]

- Omitted -

I am not the only one speculating this, Dr. Rich of hometheaterhifi.com sort of mentioned the same possibility too.

- Omitted -

/QUOTE]

It appears you agree with all of what Rich says based on your free use of his name with no supporting analysis. That is a mistake.

Just in the AV8805 review and the associated discussion of NJR and Rohm volume controls:.

Rich says the D to A, L and R channels go directly to the NRJ volume control. This isn't true, first the the L&R go through an NJR CMOS switch. In addition after the NJR volume control the L&R and all other channels go through another NJR switch. Rich seems unable to understand the analog audio diagram in the service manual that he says is in his possession, and is widely available, but he wants to keep it a secret. Use of a switch/volume control combination appears to add significant distortion vs. the volume control alone. Rich appears to not understand this situation.

Rich says the HDAM's may be responsible for the increased distortion seen in the AV8805 measurement when the output is increased from 2V to 4V, implying nothing else has changed. The HDAM's may contribute to added distortion, however the output increase is implemented by increasing the gain of the volume control in the measurements in the article. Evidently Rich believes the volume control contributes nothing to distortion. Even with a PHD, Rich evidently didn't learn that it is best to vary only one item at a time in a experiment. Rich posted the volume control/switch distortion vs. output characteristics in the associated volume control article (without crediting the source, poor form for a PHD...), but evidently didn't understand what he was posting, or ignored it, or who knows what. Changing the volume control out from 1V output to 2V output, appears to definitely increase distortion, increasing the gain can only add to this increase in distortion.

Rich compares the new NJR, NJU72343, volume control to a Rohm volume control. Yamaha uses a different Rohm volume control than Rich evaluated, with what appear to be better characteristics than the NJR volume control, especially since the Rohm control contains its own switching. The Rohm control used was available and used by Yamaha when Rich wrote the article. Rich said the Rohm control didn't provide 10k ohm load distortion characteristics. The control used by Yamaha provides these characteristics in a chart with distortion vs. signal level. The Rohm control evaluated my Rich may even be a non-current unit.

Again, you again nothing at best, by giving Rich as a source. It is best to critically analyze whatever he writes, as with about anything else on the Internet.

 

[peng]

ASR has shown that power amplifiers can have better SINAD than AVR/AVPs.
Do we know the effect of preamplifier distortion combined with amplifier distortion?

- Rich

In the AVR reviews, ASR does show the SINAD of the pre-out and the power amp output. So we can sort of see the SINAD degradation going from the power amp input to the power amp output.

The SR6014 seems to have lost about 4 to 4.5 dB SINAD, with preout at about 1.1 V and power amp output at about 120 W, approximately.

How about if Amir would pair (not that he actually would, evidently he's too busy already doing so many tests) a power amp that he has already measured, with an AVR such as the AVR-X3700H. Since he would already know the SINAD of the power amp at rated output, and we can then know the effect of the X3700H's preout's at say 1.2 V, 96 dB SINAD.

For it to work, he would have to pick one that has SINAD below 90 dB. Do you think such a test will tell us something?

 

[LTig]

In the AVR reviews, ASR does show the SINAD of the pre-out and the power amp output. So we can sort of see the SINAD degradation going from the power amp input to the power amp output.

The SR6014 seems to have lost about 4 to 4.5 dB SINAD, with preout at about 1.1 V and power amp output at about 120 W, approximately.

How about if Amir would pair (not that he actually would, evidently he's too busy already doing so many tests) a power amp that he has already measured, with an AVR such as the AVR-X3700H. Since he would already know the SINAD of the power amp at rated output, and we can then know the effect of the X3700H's preout's at say 1.2 V, 96 dB SINAD.

For it to work, he would have to pick one that has SINAD below 90 dB. Do you think such a test will tell us something?

I don't think so since one can measure the preout directly. It might make sense to measure the preout with 10 kOhm load instead of 200 kOhm. Someone needs to send @amirm a short adapter cable with a builtin load though since his AP has only 200 kOhm and 600 Ohm available.

 

[peng]

I don't think so since one can measure the preout directly. It might make sense to measure the preout with 10 kOhm load instead of 200 kOhm. Someone needs to send @amirm a short adapter cable with a builtin load though since his AP has only 200 kOhm and 600 Ohm available.

Right, I forgot the load impedance effect. I did suggested to use a 10 kohm load before but that's too work for him so he used the 600 ohm that he could do with just the AP itself. From that curve, you could extrapolate and guessimate the 10 kohm scenario, but I don't know the projected result would be valid.

 

[LTig]

Right, I forgot the load impedance effect. I did suggested to use a 10 kohm load before but that's too work for him so he used the 600 ohm that he could do with just the AP itself. From that curve, you could extrapolate and guessimate the 10 kohm scenario, but I don't know the projected result would be valid.

Well, you can certainly expect that THD at 600 Ohm is not lower than at 10 kOhm, so if the output can handle 600 Ohm with low THD it certainly can handle 10 kOhm as well. However if 200 kOhm is good and 600 Ohm is bad you still don't know what happens at 10 kOhm.

 

[amirm]

Well, you can certainly expect that THD at 600 Ohm is not lower than at 10 kOhm, so if the output can handle 600 Ohm with low THD it certainly can handle 10 kOhm as well. However if 200 kOhm is good and 600 Ohm is bad you still don't know what happens at 10 kOhm.

FYI unbalanced pre-outs are measured at 100K, not 200K

 

[peng]

Well, you can certainly expect that THD at 600 Ohm is not lower than at 10 kOhm, so if the output can handle 600 Ohm with low THD it certainly can handle 10 kOhm as well. However if 200 kOhm is good and 600 Ohm is bad you still don't know what happens at 10 kOhm.

It wasn't bad at 600 ohm, in fact iirc, Amir said distortion did not suffer, but at only 0.6V output. So I am wondering if we can safely assume, at say 12 kOhm, that is 20X of 600 ohms, distortion would not be worse, can only be better, in preamp mode of course, driving an ext amp with input impedance 10-12 kOhms.

 

[LTig]

It wasn't bad at 600 ohm, in fact iirc, Amir said distortion did not suffer, but at only 0.6V output. So I am wondering if we can safely assume, at say 12 kOhm, that is 20X of 600 ohms, distortion would not be worse, can only be better, in preamp mode of course, driving an ext amp with input impedance 10-12 kOhms.

Yes, we can.

 

[North_Sky]

Good review, straight to the point.

 

[peng]

It appears you agree with all of what Rich says based on your free use of his name with no supporting analysis. That is a mistake.

I mentioned his name when I quoted him, that's just out of respect. I thought it is common courtesy to not just quote but also provide a link to the source. I would do the same if I have something to say about something in your post I would quote what you wrote too, in this case I have to copy/paste because of the way you place the "QUOTE" sign, perhaps you can edit it. I am not sure if I agree with "all" of what he said either.

Just in the AV8805 review and the associated discussion of NJR and Rohm volume controls:.

Rich says the D to A, L and R channels go directly to the NRJ volume control. This isn't true, first the the L&R go through an NJR CMOS switch. In addition after the NJR volume control the L&R and all other channels go through another NJR switch. Rich seems unable to understand the analog audio diagram in the service manual that he says is in his possession, and is widely available, but he wants to keep it a secret. Use of a switch/volume control combination appears to add significant distortion vs. the volume control alone. Rich appears to not understand this situation.

First of all, he did not say that in the review article of the AV8805. Now that you mentioned it, I clicked on the link he provided in the review to another article (AVR build quality Part V) and found a block diagram and he said "As can be see from the above figure, the switch in the volume chip (NJU72343) brings the DAC in direct. "

Is that what you referred to? If it is, I think he wasn't talking about the circuitry of the AV8805, he seemed to be suggesting one way of routing the signal. In that beginning of that paragraph he said "If you want to build a 7.1 AVR you need just two of the New Japan Radio chips. It is medium-scale integration (MSI) that makes this possible. Just as the name sounds, an MSI chip has more transistors than an SSI chip but a lot less than an LSI chip which in turn has a tiny amount of transistors compared to today’s VLSI (Very Large Scale Integrated circuit) chips."

Link to that article:
https://hometheaterhifi.com/technic...vr-audio-video-reciever-build-quality-part-v/

Rich says the HDAM's may be responsible for the increased distortion seen in the AV8805 measurement when the output is increased from 2V to 4V, implying nothing else has changed. The HDAM's may contribute to added distortion, however the output increase is implemented by increasing the gain of the volume control in the measurements in the article.

Regarding his comments on the ... 2V to 4V ..., my interpretation is that he wanted to make the point that the distortion increase was not from the DAC. He never said the volume IC was not responsible for the THD increase and he was just making another point that the volume IC used in the 8805 compared to the LSI chip (he referred to as the AVR LSI chip Renesas LSI chips (R2A15220FP) used in the AV8801 and AV8802 pointed to 50% reduction in distortion. I could not fact check on this point as I don't have the datasheet of the R2A15220FP.

Evidently Rich believes the volume control contributes nothing to distortion.

He never said that in that review, if you saw something I didn't, I would appreciate a direct quote and link. All I could see in that review was that he tried to make the point that the DAC was not the source of added distortion, and that he expected a reduction in distortion from the new volume IC, that was not there based on the test measurements. So he suspect may be the HDAM is somehow the reason why the expected reduction of distortion was not seen, but then again he never said the HDAM was the source, he said "It is possible ...." He said that in the linked review below, in the paragraph near the end but before the conclusions.
https://hometheaterhifi.com/reviews/receiver-processor/processors/marantz-av8805-processor-review/

Even with a PHD, Rich evidently didn't learn that it is best to vary only one item at a time in a experiment. Rich posted the volume control/switch distortion vs. output characteristics in the associated volume control article (without crediting the source, poor form for a PHD...), but evidently didn't understand what he was posting, or ignored it, or who knows what. Changing the volume control out from 1V output to 2V output, appears to definitely increase distortion, increasing the gain can only add to this increase in distortion.

I don't doubt Dr. Rich's credential, no reason to, but I also have no doubt he can be wrong too, don't we all? As to increasing volume control to output from 1 V to 2 V, of course he knows distortion would increase, but it seems you missed the point that he was comparing the new MSI volume control IC to the Renesas LSI IC used in the AV8802. I suggest you re-read the review before making judgment.

Again, you again nothing at best, by giving Rich as a source. It is best to critically analyze whatever he writes, as with about anything else on the Internet.

How do you know I have not done so? That's beside the point though, how many and how often forum members do such a thing and I don't think ASR members are expected to do critical analysis on things they quote though again I do agree it is good practice to include links to the sources. I did read about the author's audio electronics background, before I have ever quotes or link his articles. If anyone is interested, please follow the link.

https://hometheaterhifi.com/author/drich/

I like the fact that you get into the technical details but in this case I think you might have misunderstood certain things Dr. Rich wrote in his review on the AV8805. I tried my best to list my own interpretation above, but as they say ymmv.

By the way, on another topic, I asked you more than once about how we should interpret the tolerance specs of the THD of the Rohm chip, or the NJU volume control chip and provided links to the data sheet before.

The partial table below is from the Rohm BD34703 KS2 datasheet

Source:
https://www.datasheets360.com/pdf/-5225953889880620514

My main question is, THD from Typ 0.0004 to Max 0.02% 400-30 kHz, so does it mean one could (probability could be very low, I assume) end up with an AVR that would have a chip with as much as 0.02% THD, that would be -74 dB and if for example, ASR happened to measure this AVR, say the RX-A3070, there would be uproar on the SINAD results. I am pretty sure I misunderstood the spec but please enlighten me.

I ask for your comments, or expert opinion, because I have the impression that you are very knowledgeable in this field. I did try to get an answer from manufacturer's customer service and received no response whatsoever.

If you don't want to answer my question or offer your opinion on this for whatever reasons, I would obviously have to respect that and would not bother you again on the same.

Thank you.

 

[Thunder240]

Yes, Gene mentioned the higher 3rd harmonic too, but THD+N did measure better, 0.0018% at 2 V, amps connected, vs -76 dB, that's 0.016% for the SR6014. Or unless I read something wrong?

Another significant difference is that the 8012’s frequency response up to 20 kHz is also a lot closer to linear. The AH graph shows slight roll off beginning at 10 kHz, but nowhere near as drastic as what Amir measured on the 6014.