Standby and in-use efficiency/heat of OSD/Outlaw/Emotiva 7-channel AB/H amps compared to Class D

[jimk1963]

New Marantz Cinema 40, good quality internal amps but unit runs pretty warm when driving my LRC B&W CWM7.4 in-walls plus 4 Preference Audio K-8LCR in-ceiling surrounds. Looking at OSD Nero XA7180, Outlaw 7000X, Emotiva BasX. OSD states “Standby Current” of 0.29A, roughly 30W. Someone reported the Outlaw as similar. I assume this means that if I control either of these w/ the Cinema 40’s 12V trigger, when I shut off the Cinema 40 I’ll still be burning 30W. That’s seriously lame if correct, roughly 22kWh per month plus unwanted heat. Emotiva doesn’t offer this spec, anyone know if it also draws 30W in Standby?

Also wondering how this compares to a more expensive Class D option, say a Nilai. I read Hypex included a standby PSU in the SMPS module to bring it down to <0.5W per EU regulations, but didn’t find that anywhere on the Hypex website. Deer Creek shows 2.25W standby for their Nilai mono block and 4.5W for the Nilai stereo version, so am I to assume 2.25Wx7 ~ 16W for a 7xNilai solution? Also not very impressive, at all, if truly in Standby mode.

Why is it an AVR like the Cinema 40 achieves 0.2W in Standby, including its amplifiers, but these amp mfrs seem to have missed the memo? Don’t get it, hard to see any good reason for wasting this much energy.

 

[jimk1963]

Same question for in-use efficiency. Numbers vary widely in reports, “up to 93%” for Nilai, maybe 50-70% for the old school AB/H models.

The real goal is to understand: in a media cabinet, which amp will run coolest?

 

[jimk1963]

Tough crowd…

Enjoying the thorough amplifier testing on this forum. Although, wondering why standby power consumption and active PAE aren’t included in the test suite?

Electronics consumers are demanding more “green” in the product design - from packaging to components to power consumption. EU regulations also come to mind. Seems like a reasonable parameter to monitor.

 

[Head_Unit]

The real goal is to understand: in a media cabinet, which amp will run coolest?

The one you put an AC Infinity fan on
Standby power and efficiency is a good topic, not sure how difficult for @amirm to dig into. End-to-end efficiency is the key because as I learned from a managing director for amplifier design, while the output stages might be very efficient, the power supply perhaps is not. That was in an automotive context, and some sake was involved, but I believe the principle to be a true one. Like so many other things, the devil is in the details, I'm certain not every Class D amp is really as efficient end-to-end as they'd like you to think, though surely more efficient than Class AB.

One answer to your question could be ATI 525NC. Runs super super cool.

 

[jimk1963]

The one you put an AC Infinity fan on
Standby power and efficiency is a good topic, not sure how difficult for @amirm to dig into. End-to-end efficiency is the key because as I learned from a managing director for amplifier design, while the output stages might be very efficient, the power supply perhaps is not. That was in an automotive context, and some sake was involved, but I believe the principle to be a true one. Like so many other things, the devil is in the details, I'm certain not every Class D amp is really as efficient end-to-end as they'd like you to think, though surely more efficient than Class AB.

One answer to your question could be ATI 525NC. Runs super super cool.

Hehe yeah, I've got AC infinity fans atop the Marantz Cinema 40 and the cable box. Also have AC Infinity temperature-controlled fans running in a third bay where the router/10GbE switches are.

Re: efficiency, yes I'm thinking end-to-end PAE, meaning if @amirm runs the amp at 200W output power into a dummy load (for example), the overall PAE is just (200 Watts) / (AC Wall Power Drawn). I would ignore subtracting the input power to the amp since it's just a high-impedance voltage input. I believe this kind of metric would be very informative, and as you said, expose any poor designs and also provide a better feel for thermal rise.

 

[Worth Davis]

Purifi and crown are room cold, my class A and AB are not. If heat is driving your decision it’s pretty obvious to go D or the like

 

[Worth Davis]

Also your marantz might be just as hot with the internal amp off, fair warning

 

[DVDdoug]

Why is it an AVR like the Cinema 40 achieves 0.2W in Standby, but these amp mfrs seem to have missed the memo?

Do the amplifiers actually have a standby mode or are they just "inactive" with no signal?

Something "modern" like an AVR is usually "off" with just the remote control receiver powered-up and running.

 

[jimk1963]

Also your marantz might be just as hot with the internal amp off, fair warning

Seems unlikely. If amps aren’t running, should be significantly less thermal overall. Guess this could be measured…