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Advice on a Class A design
Advice on a Class A design
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Old 3rd July 2020, 11:57 AM   #61
hpro is online now hpro  Switzerland
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Join Date: Apr 2012
Location: Bern, Switzerland
Default Abouut I7

Originally Posted by gilera View Post

As an aside, you get some old i7 CPUs that were rated up at 90W and these didn't have overly elaborate heat sinks - just a reasonable fan in a well ventilated case. I have a Noctua NH-L9i (92mm) fan in a mini ITX case with an Ivy Bridge i7 and it is completely silent unless your are 30cm away and it never gets hot even when running a stress test. 2 of these type fans would make for a very compact Class A build but as I said above would likely cost more that good heat sinks.

I appreciate that CPUs aren't really designed to run flat out all the time and don't in most applications so i'm not comparing apples with apples here...

As you can see in the pictures, my Laptop also run a I7 it's something 2012.. is on 2.2GHZ
First Picture shows Windows Taskmanager which is on IDLE look at the differnt Value like = Percentage, Heat Power etc

The other pictures are on Simulating Multisimm 14.
One Important thing is: Your CPU runs on 3.3Volts and not +- 42 or just even 36.

Then also INTEL CPUs, all of them having Intel Speed Step which always is on. If you switch it off *usually in the BIOS* then CPU will run at it's lowest Frequency. Here a few Pictures take from my Laptop just a few minutes ago
It's a MAC BOOK PRO 2012 , running Windows 10 Enterprise

Now again look at the FAN SPEED temps etc

If this would be a gaming computer this would be disaterous for it.

And a CLASS A is evern worse, my single end goes from 25 Degrees up tp 59 within 2 Minutes and then the FAN KICKS in, but it just turns enough to keep it below 70 Degrees, even surrounding air is 25 / 30 degrees.

So my Class A runs the less hot one runs on 37 Volts with 3.7 ampere IDLE
37x37=136 Watts per Channel delivering only 18 watts RMS into 8 Ohm the rest is HEAT

The Hot one is 42X 5.6 = 235 Watts and delivering maximum 26 Watts RMS into 8 Ohm the rest is heat.

but the sound is unsurpassed if we are talking about Transistors.
Now, just to burn less heat for nothing I'm testing a Cirquit which I can choose the POWER OUTPUT to the need of the Listener.. I have this for manual switching but I would like to have it Automatic, that the AMPLIFIER decides by itself which RE is should use and of course switches them automatically. Three Variant are Valid,:
RE 15Ohm for about 5 Watts output,

RE10 OHM for about 12.5 / 15W output depending on RAIL VOLTAGE and then the hot version

RE 7.5 Ohms output for 20+Watts Output..

If you take non FAN HEAT SINKS this will be quite large Pieces..

Hope this helps
here a pic of the AMP with active cooling heat sinks from MAC Computer G5
Attached Images
File Type: jpg ScreenShot071.jpg (140.6 KB, 50 views)
File Type: jpg 1. I7 Idle W10 Enter.jpg (197.1 KB, 50 views)
File Type: jpg 2. W10 Enter Idle.jpg (186.1 KB, 50 views)
File Type: jpg 3. W10Enterprise 35%load.jpg (282.6 KB, 47 views)
File Type: jpg 7.Amp test.jpg (231.8 KB, 50 views)
File Type: jpg 8.Temp Test.jpg (190.5 KB, 21 views)
File Type: jpg 5.Final- Bottom View.jpg (165.3 KB, 18 views)
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Old 3rd July 2020, 12:32 PM   #62
OldDIY is offline OldDIY
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Join Date: Dec 2009
Originally Posted by marshmite View Post
Does anyone have knowledge of reap airing SugdenA21a amplifiers?
Create a theme "...reap airing SugdenA21a amplifiers"


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