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Let's stop calling Class D amplifiers "efficient" when they are not.

AdamG

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You guys are so incredibly talented and creative. This thread has been a hoot and John has only posted once!

If this thread was posted by anybody other than John. We would think it a Major Forum Trolling thread. But I suspect that John has good reasons for posting this. At least I hope he does or we can chalk it up to Jack Daniel’s Posting. We all get a little depressed and confused when we pour that last shot out of the bottle. :cool:
 
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tmtomh

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You guys are so incredibly talented and creative. This thread has been a hoot and John has only posted once!

If this thread was posted by anybody other than John. We would think it a Major Forum Trolling thread. But I suspect that John has good reasons for posting this. At least I hope he does or we can chalk it up to Jack Daniel’s Posting. We all get a little depressed and confused when we pour that last shot out of the bottle. :cool:
I’m sure he has reasons. Good reasons… not so sure about that. :)

I think it’s about 8:30am in Australia right now, still maybe we’ll find out in a couple of hours.
 

Rick Sykora

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You guys are so incredibly talented and creative. This thread has been a hoot and John has only posted once!

If this thread was posted by anybody other than John. We would think it a Major Forum Trolling thread. But I suspect that John has good reasons for posting this. At least I hope he does or we can chalk it up to Jack Daniel’s Posting. We all get a little depressed and confused when we pour that last shot out of the bottle. :cool:

John has been very efficient in this thread. At least Class D in my opinion.;)
 

mhardy6647

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LEDs ruin the sound, anyways.
That's why the cool kids use VFDs... for triodes. ;) :cool:


 

fpitas

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That's why the cool kids use VFDs... for triodes. ;) :cool:


but still features the same 2N3904 input and 2N7002 output stage o_O
 

fpitas

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DonR

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I took it meant to type onus.
That really doesn't help. There may have been some Freudian slips passing through his brain to go from onus to anis but missing the obvious spelling mistake intentionally.:p
 

Music1969

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but missing the obvious spelling mistake intentionally.:p

Too much anal ysing here people.

Just enjoy the intentional typo - definitely no personal attack intended.

I enjoy a lot of restorer john's posts for years here

I assume he had a few drinks before starting this thread
 

antennaguru

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Actual Power Consumption Measurements of simple Audio System, playing music over various power amplifiers:


Notes: Nakamichi 630 Preamp Tuner receiving a Jazz station and powering various power amplifiers to moderately high peak volume level over 86 dB efficient passive loudspeakers. Measurements made with a Wattmeter connected to the AC power source, and recording in kWh (Kilowatt-Hours) for 1 timed hour.

  1. Class D IcePower 125ASX2 module with Class A input buffer stage.
  2. Class AB LM3886 Chip Amp using large linear PS.
  3. Class AB Naim NAP-250 Clone (discrete transistors) using large linear PS.
  4. Class A 25wpc using discrete components using large linear PS.
kWh used in one hour of operation:

  1. 0.026 kWh
  2. 0.030 kWh
  3. 0.027 kWh
  4. 0.185 kWh

The kWh can be converted to $ per month as would be seen in a monthly electrical bill by making an assumption of on-time hours per month, and applying the "all-in electrical utility rate for a specific area". Unfortunately, the all-in rate (energy cost PLUS delivery cost) varies quite substantially by specific area, and with many areas having different summer and winter rates.
 

DonR

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Too much anal ysing here people.

Just enjoy the intentional typo - definitely no personal attack intended.

I enjoy a lot of restorer john's posts for years here

I assume he had a few drinks before starting this thread
It's a dirty and dark hole this thread is.
 

McFly

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Nice Troll thread John :cool:

People need to stop talking about Watts (the REAL power we pay for) and start talking about VA (the Apparent Power which is work the poor power station actually does).

So many amplifiers have power factors of 0.5-0.7. They may only be consuming 100W, but they are really using 150-200VA.

Power consumption should be measured in VA, if we are going to be more climate conscious.
 

raif71

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It's efficient when you actually need it, I don't see a problem.
grade-a-iu.jpg
 

JaccoW

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Actual Power Consumption Measurements of simple Audio System, playing music over various power amplifiers:

kWh used in one hour of operation:

  1. 0.026 kWh
  2. 0.030 kWh
  3. 0.027 kWh
  4. 0.185 kWh

The kWh can be converted to $ per month as would be seen in a monthly electrical bill by making an assumption of on-time hours per month, and applying the "all-in electrical utility rate for a specific area". Unfortunately, the all-in rate (energy cost PLUS delivery cost) varies quite substantially by specific area, and with many areas having different summer and winter rates.
Excellent.

So where I live the untaxed electricity rates were historically about €0.040/kWh but spiked to €0.447/kWh last winter. An 11x increase. Currently it sits at about €0.099/kWh.

So assuming 10 years of use, 350 days a year at 4 hours per day; (Excluding taxes (21%) and fixed costs)

Historic rate:
€0.040/kWh
Total usage
Cost
0.026 kWh​
91 kWh​
€3.64​
0.030 kWh
105 kWh​
€4.20​
0.027 kWh
95 kWh​
€3.78​
0.185kWh
647 kWh​
€25.90​

High rate:
€0.447/kWh
Total usage
Cost
0.026 kWh​
91 kWh​
€40.68​
0.030 kWh
105 kWh​
€46.94​
0.027 kWh
95 kWh​
€42.24​
0.185kWh
647 kWh​
€289.43​

Current rate:
€0.099/kWh
Total usage
Cost
0.026 kWh​
91 kWh​
€9.01​
0.030 kWh
105 kWh​
€10.40​
0.027 kWh
95 kWh​
€9.36​
0.185kWh
647 kWh​
€64.10​
 

Prana Ferox

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I'm still a little confused on if John really wants to focus on the efficiency of an amplifier when it's not amplifying, which he certainly understands has nothing to do with amp topology and more to do with the power supply and whatever parasitic loads are in the box. But alternately, you can look at pro amplifiers and see that as through the years they transition (and a good part of why they transition) from AB lead sleds to class D, they significantly reduce the included heat sinks and in some cases noticeably shrink in size along with the weight loss. This is because (when amplifying, of course) class D generates significantly less heat per watt output, so you can make do with a lot less extra stuff in the box and the amps still survive. This isn't some conspiracy from Big Heatsink Value Engineering.
 
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