Big news coming from Sound United in 2023!

[Doodski]

120 V * 15 A * 1.25 = 2,250 W

What is the 1.25 stuff. I don't get that part.

 

[peng]

If you are referring to the 92% efficiency figure which I assumed for the sake of a quick calculation, it was for the entire unregulated non-switching power supply (i.e. incl. transformer, rectifier, block caps and related circuitry) and not just the transformer (whose efficiency is likely in the mid- to upper-90s%).

The dimmed halogen lights in my HT room, connected to the same 15 A circuit that powers my old AVR, actually go out every time the AVR is powered on (unfortunately, unlike in the previous home, I do not have a dedicated 20 A line for the A/V equipment). So, yes, I do realize the CB will not trip with a massive but short overload.

It isn't a "If", I was clear in my post, even attached a data sheet that is for the transformer only.

 

[peng]

What is the 1.25 stuff. I don't get that part.

I think he might have referred to what was said in the article he linked, that talked about sizing circuit breaker, that is not the same as sizing the feeder cable for the load. Two different, though somewhat related topics. For example, the feeder may be rated for a continuous load that draws 12 A, the circuit breaker could be sized (or rated) for up to 1.25X12, or 15 A. Distinction needs to be made between "non continuous load" and "continuous load". AVRs are clearly not considered "continuous load", I think we can all agree on that..

 

[lc6]

It isn't a "If", I was clear in my post, even attached a data sheet that is for the transformer only.

Well, so where in my post did I say that the transformer was less efficient than the 94% sample figure you quoted to prove me wrong?

 

[lc6]

What is the 1.25 stuff. I don't get that part.

From the NEC rules for continuous loads (e.g. a hair dryer, unless "pulsed" for fun); see my earlier post.

 

[Karls_speaker_works]

Ugh, I'm a power engineer but I would prefer to click in and see posts about the new AVR units vs bickering about power consumption.

 

[ryanosaur]

Ugh, I'm a power engineer but I would prefer to click in and see posts about the new AVT units vs bickering about power consumption.

Welcome to ASR!

 

[wseroyer]

If that is true, it is a safety issue. That is because most residential circuits are 15 A, which means 1,800 W, and other devices are typically plugged into them. Every device should have a clear specification of the max. power consumption to avoid circuit overload (a safety margin of at least 20% is recommended, which reduces the standard line to 1,440 W).

Watch Gene's video he explains why this isn't a safety issue, nobody is going to run a continues sine wave for minutes on end at full volume, this is not a normal operating condition.

 

[lc6]

0.75 pf is very a very reasonable assumption, though a little on the conservative side imo (a good thing for safety). I would avoid using SF on things related to electrical safety codes because SF will typically mean service factor, not safety factor.

If you are asking about safety factor consideration for an AVR load, I don't have an answer. You can understand why if you consider some examples:

A) Someone using an AVR to power 5 speakers with 92 dB/W/m sensitivity, sitting 3 meters and listening to 10 dB below reference:
Power required = about 3.5 W, assuming eff at such low output level = 15%, power consumption = 3.5/.12 = 23.3 W, current = 23.3/120/.75 = 0.324 A, or 5X.324 = 1.62 A

B) Someone using the same AVR to power 5 speakers with 89 dB/W/m, same seating distance, same listening spl:
Power required = 7 W, assuming the same efficiency, Power consumption = 7 W/0.15 = 46.67 W, current = 46.67/120/.75 = 0.519 A, or 5X.519 = 2.6 A

C) Somone using the same AVR for the same conditions but listens to reference level (this means 105 dB peak with just one speaker):
Power required = 175 W, Power consumption would then be about 175/120/0.8/0.8 = 2.28 A, or 5X2.28 = 11.4 A

So if you consider scenario C) above, for some who always listen at reference level, at 3 meters distance using 89 dB/W/m speakers in 5 channel stereo mode, current draw will still be below 12 A (80% of 15 A).

But it depends so much on the individual's speakers and listening habit so it doesn't seem practical to consider "safety factor". Besides, it is an audio device that is protected by not only the circuit breaker, but also the device's protective system that nowadays almost always offer protection against short circuit current, overcurrent, thermal overall current, dc offset, and potentially more. Also, unlike baseboard heaters, fan, pump motors, audio devices naturally don't get as much attention from the regulatory authorities, and are not even mentioned specifically in electrical code books.

Think about his, we even have a thread on ASR named "FTC may drop the amplifier rules", that tells you how keen the regulatory authorities are on audio devices. I guess to them they are low risk, never resulted in much major accidents (may be the odd small fires), injuries etc..

FTC may drop amplifier rules

https://www.stereophile.com/content/ftc-proposes-eliminating-its-amplifier-rule Seems strange and short sighted to drop the whole rule rather than modify it. Then again it appears there is pretty much zero enforcement. Still hard to see how this benefits the consumer. Heck they need a new rule...

www.audiosciencereview.com

I am having trouble following some of your calculations. In A) you assume an efficiency of 15%, but then you divide by 0.12. In C), you are dividing by a different PF=0.8 twice (unless the second 0.8 is meant to be the efficiency of the amp, which at 80% would be unrealistically high for class A/B). And you are not taking into account the efficiency of the power supply or the fixed front-end overhead. But, alright, I get the gist.

I think we beat the AVR power-consumption horse to death now, but in closing I would say that in the old days of stereo power amps of < 100 W per channel, the typical home electrical circuits were not an issue, but with powerful multi-channel amps and AVRs, they increasingly are.

 

[peng]

I am having trouble following some of your calculations. In A) you assume an efficiency of 15%, but then you divide by 0.12. In C), you are dividing by a different PF=0.8 twice (unless the second 0.8 is meant to be the efficiency of the amp, which at 80% would be unrealistically high for class A/B). And you are not taking into account the efficiency of the power supply or the fixed front-end overhead. But, alright, I get the gist.

Sorry I assumed lower efficiency for the lower output scenario because for class AB amps efficiency is not constant, it follows a curve that typically show lower efficiency at lower output level. At rated output and slightly higher efficiency would improve to even 0.75/75% is not uncommon and even 0.8 is possible so I used it in the last example to exaggerate how the calculations could change for different scenarios.

When I divided it by 0.8 twice it was because the first 0.8 was the assumed super high efficiency (sort of best case scenario) and the second 0.8 was the power factor, that could also be higher than Gene's assumption of 0.75 so again just to show the best possible numbers.

 

[CyrusTheGreat_600BC]

the Marantz sound is cutting off half of the human hearing spectrum apparently.

Half is for the average Joes. Imagine how much it’s if you’ve a super or trained hearing. Marantz is waste of time and money. I’ve had 8 units over the years, and still own 3 smaller amps, but never would buy another Marantz again. They are prettier than Denon though, I give them that. Even speaker terminals have better quality and look prettier.

 

[polmuaddib]

the Marantz sound is cutting off half of the human hearing spectrum apparently.

What are you talking about? What test, review can you offer as proof?
Amir measured three marantz AVPs and found worse SINAD then Denon counterparts, but not half of the frequency response chopped!
Worse SINAD is not the same as FR and the audibility of it is questionable. We have no double blind tests of Denon and Marantz AV devices that I know of.
So, please, if you have some information on a test which shows FR audible issues, list it.
Thank you

 

[Sancus]

What are you talking about? What test, review can you offer as proof?
Amir measured three marantz AVPs and found worse SINAD then Denon counterparts, but not half of the frequency response chopped!

A bit of an exaggeration, but Marantz uses slow filters on all of their units that result in audible high frequency droop. Not audible to those with significant HF hearing loss perhaps, but -0.5dB at 15khz is shockingly poor for a piece of electronics that should be perfectly flat like every other half-decent piece of electronics made by anyone.

This is much worse than inaudible SINAD differences. If you care about SINAD at all, then you should care a LOT more about this.

And I quote from the AV7705 review:

It is simple: Marantz group takes perfectly good platform uses in its sister Denon division and screws it up across the board. Everything is degraded no matter what we test. It really is time for Marantz to go back to producing well engineered products rather than chasing subjective aspects they can't demonstrate. And poor notions like the slow reconstruction filter. It is depressing to test an AV product in 2021 with such poor performance.

 

[voodooless]

A bit of an exaggeration, but Marantz uses slow filters on all of their units that result in audible high frequency droop. Not audible to those with significant HF hearing loss perhaps, but -0.5dB at 15khz is shockingly poor for a piece of electronics that should be perfectly flat like every other half-decent piece of electronics made by anyone.

This is much worse than inaudible SINAD differences. If you care about SINAD at all, then you should care a LOT more about this.

Nothing Audyssey won't fix I always wondered why it added so much gain above 10 kHz, now I understand.

 

[peng]

Nothing Audyssey won't fix I always wondered why it added so much gain above 10 kHz, now I understand.

Also, the slow filter has negligible effect on FR for contents with sampling rate at 48 kHz or higher, and no effects (in FR) if analog inputs and direct mode are used.

 

[Oniiz86]

@DrStranger It looks like the new 2022/23 models do support QMS after all but apparently not the latest revised spec of QMS, I know What Hi-Fi isn't a reliable source when it comes to reviews, here is their recent X3800H review, https://www.whathifi.com/reviews/denon-avc-x3800h
"Denon says that as HDMI.org has updated its specifications for QMS (Quick Media Switching), the AVC-X38000H can handle the old standard (as the AVC-X3700H did), but not the latest changes. We can't imagine that being a major issue for anyone though."

 

[DrStranger]

@DrStranger It looks like the new 2022/23 models do support QMS after all but apparently not the latest revised spec of QMS, I know What Hi-Fi isn't a reliable source when it comes to reviews, here is their recent X3800H review, https://www.whathifi.com/reviews/denon-avc-x3800h
"Denon says that as HDMI.org has updated its specifications for QMS (Quick Media Switching), the AVC-X38000H can handle the old standard (as the AVC-X3700H did), but not the latest changes. We can't imagine that being a major issue for anyone though."

So what does this mean? Did they use a older HDMI controler? If so, Do we know the difference between the old and new? Could it be that HDMi did changes from 2.1 to HDMI 2.1a and thats what they mean?

I still dont understand why they dont write that it has this, even Marantz have not written QMS support.

Highly confusing I must say...

 

[DrStranger]

Can someone explan this to me, the Q&A someone is asking about turning off the internal amps and they say no:

AVR-X3800H - 9.4 Ch. 105W 8K AV Receiver with HEOS® Built-in | Denon - US

The AVR-X3800H 9.4 Ch. 105W 8K AV Receiver with HEOS® Built-in from Denon provides high quality audio for your hi-fi needs. Explore more AV Receivers at Denon - US.

www.denon.com

But the manual mention something about the individual control?

Connecting an external power amplifier AVR-X3800H

manuals.denon.com

 

[GXAlan]

Now thats a good link of info, that site did not spare anything. Thank you.

For the dac, they talk about topology and power supply. The new stuff has the same topology but the x4800h and lower do NOT have a dedicated power supply for the digital section.

I am not sure exactly what the "96 x t65" means, but assuming it is the size of the transformer core (as opposed to its exterior) and plugging these numbers into a sample transformer calculator (while keeping the core efficiency at the default 0.82) results in the core area of 6,240 mm^2 and the apparent power of 2,058 VA.

Not a French speaker but probably taille as used for height based upon the slides on the capacitors.

The one nice thing about Denon & Marantz is that while they have been known to cook their own HDMI boards, I do believe their electronics are UL listed and

Can someone explan this to me, the Q&A someone is asking about turning off the internal amps and they say no:

AVR-X3800H - 9.4 Ch. 105W 8K AV Receiver with HEOS® Built-in | Denon - US

The AVR-X3800H 9.4 Ch. 105W 8K AV Receiver with HEOS® Built-in from Denon provides high quality audio for your hi-fi needs. Explore more AV Receivers at Denon - US.

www.denon.com

But the manual mention something about the individual control?

Connecting an external power amplifier AVR-X3800H

manuals.denon.com

There may be individual control of unplugging the preamp to the amp section to improve sinad. The amps themselves still have idle current so they are not fully powered down so whatever level of class A bias is still generating some heat.

 

[DrStranger]

For the dac, they talk about topology and power supply. The new stuff has the same topology but the x4800h and lower do NOT have a dedicated power supply for the digital section.



Not a French speaker but probably taille as used for height based upon the slides on the capacitors.

The one nice thing about Denon & Marantz is that while they have been known to cook their own HDMI boards, I do believe their electronics are UL listed and


There may be individual control of unplugging the preamp to the amp section to improve sinad. The amps themselves still have idle current so they are not fully powered down so whatever level of class A bias is still generating some heat.

Thank you.