Marantz AV 10 15.4CH AV Processor Bench Test Results!

[L_avocat]

To follow

 

[PENG]

Yeah it does perform nicely beyond specs, so no complaints there, I just find it odd on a technical level.

but I did notice that it basically tops out at about 1-1.2 kW total power even in 7 ch drive, so perhaps it’s just hitting a max PSU limit or something. Would be interesting to see bridged single channel results, though that’s not very relevant for a 16 channel amp anyway

I misunderstood your point initially. Not "odd" as such imo as it is not that uncommon in the real world, there are just practical limits such as PSU related, that you alluded to.

Theoretically, output should increase 2X when the load impedance is halved, and 4X if the voltage doubles (bridged mode). In this case, 500 W is well below the 800 W theoretical limit, so there obviously are some limitations. Whether it is a PSU, heat dissipation related or other issues, would depend in the design, that we are not going to know. Gene could probably find out from Marantz, if he has a way to contact their design team.

As you mentioned, PSU is most likely one of the "limits", especially for multichannel amps, but again, there are likely other factors.

Like the double down thing, the quadruple thing in the case of BTL configuration also would rarely result in the theoretical gain in output if you look through the specs of many such amps. Some amps (example: AHB2) do get very close though, but would also likely be rated at (or measured on test benches) higher distortions at or near those upper limits.

 

[dlaloum]

I misunderstood your point initially. Not "odd" as such imo as it is not that uncommon in the real world, there are just practical limits such as PSU related, that you alluded to.

Theoretically, output should increase 2X when the load impedance is halved, and 4X if the voltage doubles (bridged mode). In this case, 500 W is well below the 800 W theoretical limit, so there obviously are some limitations. Whether it is a PSU, heat dissipation related or other issues, would depend in the design, that we are not going to know. Gene could probably find out from Marantz, if he has a way to contact their design team.

As you mentioned, PSU is most likely one of the "limits", especially for multichannel amps, but again, there are likely other factors.

Like the double down thing, the quadruple thing in the case of BTL configuration also would rarely result in the theoretical gain in output if you look through the specs of many such amps. Some amps (example: AHB2) do get very close though, but would also likely be rated at (or measured on test benches) higher distortions at or near those upper limits.

Without looking at seriously overengineered amps like Krell (which possibly achieve doubling specs by under specifying the 8ohm and 4ohm ratings?)....

I use my Crown XLS2500 amps as a "benchmark" of very good performance into difficult low impedance loads:

8ohm 440W
4ohm 770W (1.75x 8ohm)
2ohm 1200W (1.56x 4ohm)

I look at amps that rate 4 ohm at only 1.5x the 8ohm rating as being compromised in terms of difficult load handling.

The other thing to watch out for, is some amp designs will output clean power into very difficult loads, but will not achieve high power outputs - ie: they are stable into very low impedance loads, but may not have the power supply to support high power outputs... (my Quad 606 being an example of this genre... it can drive 1 ohm but only puts out 40W RMS into 1 ohm... (yes it sounds just fine with difficult speakers...not obviously different from the Crown which has heaps more power)

But any amp that gets pretty close to the impedance multiplying factors of the Crown is likely to handle pretty much any load without strain...

519/400 = 1.25 - so it is clearly hitting constraints (based on the multiplying factor)... but it can put a serious amount of power into that load, so the constraints are pretty much academic!

 

[Quantumboredom]

On to a different question about the AV 10, does anyone know if the AV 10 is properly designed to be immune to ground loop humm/noise when using balanced amplifiers? My Marantz AV7706 is not, as it suffers from slight noise with my PC off, and extreme noise (from rendering, mouse pointer movement etc.) with the PC on. This seems to occur because both the PC (connected to the AVR via HDMI) and my power amps (Hypex NC502MP) are grounded. If I break the loop by either lifting the ground on my PC or break the XLR ground the noise is gone.

From what I understand this should not happen with properly constructed balanced audio equipment, at least according to the sources I can find. E.g. Hypex or Rane.

It’s possible to make it work of course, but it would be very annoying to spend so much and still have to fight ground loop problems that properly designed equipment shouldn’t be experiencing in the first place.

 

[AcuDefTechGuy]

On to a different question about the AV 10, does anyone know if the AV 10 is properly designed to be immune to ground loop humm/noise when using balanced amplifiers? My Marantz AV7706 is not

I doubt anything is immune to ground loop, not even FULLY BALANCED components from Input to Output.

My fully balanced ATI amps and fully balanced Denon AVP-A1HDCI had the ground loop hum-noise at my previous house, but did not have any ground loop at my new house.

So I doubt the AV10 is immune to all ground loop.

 

[ban25]

On to a different question about the AV 10, does anyone know if the AV 10 is properly designed to be immune to ground loop humm/noise when using balanced amplifiers? My Marantz AV7706 is not, as it suffers from slight noise with my PC off, and extreme noise (from rendering, mouse pointer movement etc.) with the PC on. This seems to occur because both the PC (connected to the AVR via HDMI) and my power amps (Hypex NC502MP) are grounded. If I break the loop by either lifting the ground on my PC or break the XLR ground the noise is gone.

From what I understand this should not happen with properly constructed balanced audio equipment, at least according to the sources I can find. E.g. Hypex or Rane.

It’s possible to make it work of course, but it would be very annoying to spend so much and still have to fight ground loop problems that properly designed equipment shouldn’t be experiencing in the first place.

PC audio is a mess. That noise from your GPU, that changes frequency based on what's on screen is not a ground loop. Two things to try:

1. Use Toslink optical from your PC to your AVP. That will break any ground loops.
2. Get a cheap external USB DAC and use that as your PC audio output. That will eliminate any noise from poorly isolated components on the motherboard.

 

[Trell]

PC audio is a mess. That noise from your GPU, that changes frequency based on what's on screen is not a ground loop. Two things to try:

1. Use Toslink optical from your PC to your AVP. That will break any ground loops.
2. Get a cheap external USB DAC and use that as your PC audio output. That will eliminate any noise from poorly isolated components on the motherboard.

And if there is still is noise issues related to ground loops using an external USB DAC there are USB galvanic isolators available, and recently there are relatively inexpensive ones that performs very well, like the one from Topping. See the two post below from RME:

Topping HS02 USB2.0 Audio Isolator (Page 1) — ADI-2 & 2/4 Pro series, ADI-2 DAC series — RME User Forum

ADI-2 DAC fs usb/coax implementation (Page 1) — ADI-2 & 2/4 Pro series, ADI-2 DAC series — RME User Forum

 

[PENG]

On to a different question about the AV 10, does anyone know if the AV 10 is properly designed to be immune to ground loop humm/noise when using balanced amplifiers? My Marantz AV7706 is not, as it suffers from slight noise with my PC off, and extreme noise (from rendering, mouse pointer movement etc.) with the PC on. This seems to occur because both the PC (connected to the AVR via HDMI) and my power amps (Hypex NC502MP) are grounded. If I break the loop by either lifting the ground on my PC or break the XLR ground the noise is gone.

From what I understand this should not happen with properly constructed balanced audio equipment, at least according to the sources I can find. E.g. Hypex or Rane.

It’s possible to make it work of course, but it would be very annoying to spend so much and still have to fight ground loop problems that properly designed equipment shouldn’t be experiencing in the first place.

The schemes are going to be virtually the same if not exactly the same. First of all, the noise you were getting with the AV7706 may not be ground loop related and if that's the case, balanced connection may or may not be able to eliminate such noises. If it is in fact from ground loop or other noises that are eliminated or much reduced by the common mode rejection principle , then since I doubt Marantz would have their balanced connections incorrectly, you probably should check your cable/connectors for proper connections. I had used my previous Marantz AVP and now a Denon AVR, in this case RCA to XLR input of my NC502MP buckeye amp and I had/have not experienced audible ground loop issues.

Have you read the Hypex and Rane document and check that your XLR cable/connectors have connected properly per AES48 standard?

I linked the following before when there were similar threads/posts but easy enough to do it again for you:

AN Dealing with legacy pin 1 problems (hypex.nl)
Sound System Interconnection (ranecommercial.com)

 

[Quantumboredom]

PC audio is a mess. That noise from your GPU, that changes frequency based on what's on screen is not a ground loop. Two things to try:

1. Use Toslink optical from your PC to your AVP. That will break any ground loops.
2. Get a cheap external USB DAC and use that as your PC audio output. That will eliminate any noise from poorly isolated components on the motherboard.

First of all, the noise you were getting with the AV7706 may not be ground loop related and if that's the case, balanced connection may or may not be able to eliminate such noises.

I guess it depends on how we define a ground loop problem, but I kind of feel it’s related since it only occurs when there is a loop in the grounding, but disappears when the loop is interrupted.

Have you read the Hypex and Rane document and check that your XLR cable/connectors have connected properly per AES48 standard?

I linked the following before when there were similar threads/posts but easy enough to do it again for you:

AN Dealing with legacy pin 1 problems (hypex.nl)
Sound System Interconnection (ranecommercial.com)

I’m pretty sure they are correctly done yes. At least Apollon (one of my Hypex NC502MP amps) has pretty good reputation for assembly quality. The problem is also there with either my KJF MA-01 or Crown XLS 1502, so I doubt all of them are poorly constructed.

I’ve ordered a iFi GND Defender to see if that fixes the issue, but it’s annoying regardless. I wish HDMI was galvanically isolated like ethernet is so we wouldn’t have these problems.

Edit: re. not using HDMI to the receiver I haven’t tried that, but there might still be a loop through the TV as both the PC and AVP obviously must be connected there. Also it would be annoying to not have the A/V switching be handled by the AVR.

And just to bring it back to the AV10 and similar high-end units, I wish they would galvanically isolate the HDMI circuits from the audio circuits, since a quick search will show that this is a common problem. That would be a feature worth paying a premium for!

 

[PENG]

I guess it depends on how we define a ground loop problem, but I kind of feel it’s related since it only occurs when there is a loop in the grounding, but disappears when the loop is interrupted.

I referred to the AVP and the Hypex amp only, that they likely did not cause the ground loop, and even then I did use the word "may" (anything is possible), sorry for not being specific.

To me, there is a better chance that the "loop" might have been created elsewhere, likely the cable/connector. As mentioned, did you check to see how your XLR cables are wired at both ends to the connectors and see if they are wired to AES48? If not, it's an easy fix, probably a side cutter will do. If wired correctly, then I don't know what the root cause is, as you have already read Rane and Hypex papers so you also know that one of the common issue is the so called "pin 1 problem" that Hypex referred as entirely self-inflicted (not by you obviously).

Here's a clear diagram that compares the wrong and the right.

Pin 1 Problem

I’m pretty sure they are correctly done yes. At least Apollon (one of my Hypex NC502MP amps) has pretty good reputation for assembly quality. The problem is also there with either my KJF MA-01 or Crown XLS 1502, so I doubt all of them are poorly constructed.

That seems to support my thinking that it could be something else outside of the AVP and the power amp, such as the cables/connectors, but again it is just a may be..

I’ve ordered a iFi GND Defender to see if that fixes the issue, but it’s annoying regardless

.

That's probably a well engineered product that should work without forgoing safety, but before investing in one, it is easier to eliminate the possibility of an easy fix if the cable/connector is the cause. In reading the specs, I am not sure if the Defender might limit current, 10 A continuous is not bad but there is no specs for peak current, regardless it won't likely affect audible sound quality issue except under some extreme conditions.

I wish HDMI was galvanically isolated like ethernet is so we wouldn’t have these problems.

That would be nice but may be a tall order as manufacturers won't like the added costs unless they perceive it as really necessary such as widespread complaints. I have had quite a few HDMI AVRs, AVPs, and other HDMI devices, never experienced ground loop issues, though read about quite a few posts by those who did for sure.

And just to bring it back to the AV10 and similar high-end units, I wish they would galvanically isolate the HDMI circuits from the audio circuits, since a quick search will show that this is a common problem. That would be a feature worth paying a premium for!

I would be interested to know if those higher end (price wise at least) products such as those offered by Trinnov, Stormaudio, Focal Astral, Dataset, AudioControl etc., offer such features.

 

[Golfx]

I guess it depends on how we define a ground loop problem, but I kind of feel it’s related since it only occurs when there is a loop in the grounding, but disappears when the loop is interrupted.


I’m pretty sure they are correctly done yes. At least Apollon (one of my Hypex NC502MP amps) has pretty good reputation for assembly quality. The problem is also there with either my KJF MA-01 or Crown XLS 1502, so I doubt all of them are poorly constructed.

I’ve ordered a iFi GND Defender to see if that fixes the issue, but it’s annoying regardless. I wish HDMI was galvanically isolated like ethernet is so we wouldn’t have these problems.

Edit: re. not using HDMI to the receiver I haven’t tried that, but there might still be a loop through the TV as both the PC and AVP obviously must be connected there. Also it would be annoying to not have the A/V switching be handled by the AVR.

And just to bring it back to the AV10 and similar high-end units, I wish they would galvanically isolate the HDMI circuits from the audio circuits, since a quick search will show that this is a common problem. That would be a feature worth paying a premium for!

Just to be clear, I believe PENG is NOT talking about the connectors ON the apollon. Instead he is referring to the interconnect CABLES in between the AVP and the amp being improperly wired.

 

[Quantumboredom]

That's probably a well engineered product that should work without forgoing safety, but before investing in one, it is easier to eliminate the possibility of an easy fix if the cable/connector is the cause. In reading the specs, I am not sure if the Defender might limit current, 10 A continuous is not bad but there is no specs for peak current, regardless it won't likely affect audible sound quality issue except under some extreme conditions.

It’s rated at 7 A continuous current, which for me with 230 V means 1.6 kW. Plenty for either computers or amplifiers

 

[TankTop5]

Without looking at seriously overengineered amps like Krell (which possibly achieve doubling specs by under specifying the 8ohm and 4ohm ratings?)....

I use my Crown XLS2500 amps as a "benchmark" of very good performance into difficult low impedance loads:

8ohm 440W
4ohm 770W (1.75x 8ohm)
2ohm 1200W (1.56x 4ohm)

I look at amps that rate 4 ohm at only 1.5x the 8ohm rating as being compromised in terms of difficult load handling.

The other thing to watch out for, is some amp designs will output clean power into very difficult loads, but will not achieve high power outputs - ie: they are stable into very low impedance loads, but may not have the power supply to support high power outputs... (my Quad 606 being an example of this genre... it can drive 1 ohm but only puts out 40W RMS into 1 ohm... (yes it sounds just fine with difficult speakers...not obviously different from the Crown which has heaps more power)

But any amp that gets pretty close to the impedance multiplying factors of the Crown is likely to handle pretty much any load without strain...

519/400 = 1.25 - so it is clearly hitting constraints (based on the multiplying factor)... but it can put a serious amount of power into that load, so the constraints are pretty much academic!

I had a NAD 705 that far exceeded its specs. Rated at 40 watts at 8ohms, someone bench tested it and it was stable at 1ohm at 292 watts.

 

[PENG]

I had a NAD 705 that far exceeded its specs. Rated at 40 watts at 8ohms, someone bench tested it and it was stable at 1ohm at 292 watts.

That's very interesting, enough to make me search for it's specs and found the following:

So, as expected, NAD indulge in the IHF dynamic power that generally means the duration would be limited to 20 millisecond.

Yamaha does the same thing and per their website:

To measure dynamic power, an amplifier is fed a 1000 Hz signal for 20 milliseconds then allowed to rest for 480 milliseconds.

NAD uses the same standard so it would be the same.

An amp that measured under such standard does not mean it would output the measured as "stable", not for 20 ms obviously.

Also note that the amp weighs only 14 lbs, 1 ohm, 292 W would mean 17.1 amperes! It it could actually do that, it would be for very short duration, even less than 20 ms for sure. Still such NAD amps (again, like Yamaha) are known to do well under very short durations.

 

[TankTop5]

That's very interesting, enough to make me search for it's specs and found the following:

So, as expected, NAD indulge in the IHF dynamic power that generally means the duration would be limited to 20 millisecond.

Yamaha does the same thing and per their website:


NAD uses the same standard so it would be the same.

An amp that measured under such standard does not mean it would output the measured as "stable", not for 20 ms obviously.

Also note that the amp weighs only 14 lbs, 1 ohm, 292 W would mean 17.1 amperes! It it could actually do that, it would be for very short duration, even less than 20 ms for sure. Still such NAD amps (again, like Yamaha) are known to do well under very short durations.

View attachment 69999

And I learned something new, thanks. It would be nice if more companies would design and rate their equipment similarly. Obviously not continuous power but it shows solid engineering

 

[dlaloum]

I had a NAD 705 that far exceeded its specs. Rated at 40 watts at 8ohms, someone bench tested it and it was stable at 1ohm at 292 watts.

Nice - circa 300W at 1ohm is roughly the theoretical doubling for each halving of impedance from 40W@8ohm.

However, I would bet that the 292W@1ohm was for a short period - and not a continuous reading...

My Quad 606 can do 40W@1ohm continuous but more than 90W@1ohm peak....

292W would require circa 17A... and I doubt the NAD 705 could provide 17A continuously.... although briefly from the capacitor reserves, certainly. (period reviews do mention the 705 doing 160W into 2 ohm for brief transients).

Classic NAD was always good...