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!