Wich heatsinks need an amp in class A with a total heat disipation of 520W with a total bias 11A giving 120W RMS at 8 ohms load?
Schematics:
Schematics:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
520 watts says it all. You want about 25 deg C rise above
ambient, and that means 25/520 = .047 deg / watt
heat sink rating.
😎
ambient, and that means 25/520 = .047 deg / watt
heat sink rating.
😎
Because I supposed will be better a post in the Pass Labs forum due to the fact it's a NP design.
It's ok the schematic? because BobEllis answered me in the Solid State forum:
http://www.diyaudio.com/forums/solid-state/182800-heatsinks-class-amp-question-2.html#post2464090
http://www.diyaudio.com/forums/solid-state/182800-heatsinks-class-amp-question-2.html#post2464090
A heatsink, with that capacity? Several words come to mind: cryostat, liquid nitrogen, dewar jar, etc, etc
If you are seriously considering building this thing you could do it with 4 x conrad mf35-151.5 per channel. So 8 total, but it will still be quite hot. If you want a cool running amp make it 6 per channel.
And don't think about stacking the heatsinks on top of each other because you lose efficiency.
Probably a cube shape heatsinks on all 4 sides
And don't think about stacking the heatsinks on top of each other because you lose efficiency.
Probably a cube shape heatsinks on all 4 sides
With that much aluminum it would take hours to thermally stabilize....so just leave it on all the time your power company will love you, however it will sound great !!!
regards, Elwood
regards, Elwood
hahaha wow Merlin, now thats something. just build a listening room with open beam structure and attach the amp to one of the supports 😉 bring new meaning to the words sound system installation
This project starts to be very difficult, who knows another Pass class A with less power & easy to do (my friend search something 100W), if exist a GB for pcb will be perfect, thanks for all your answers guys.
Any class A amp at 100W will require a huge amount of heat sinking. Is there any reason your friend is stuck on 100W? Can you build him the same amp that you have? Two ways to reduce the amount of heat sink - lower the power requirement, go class AB.
As I mentioned in your other thread, the AJ-x on Peter Daniel's boards can be scaled to nearly any power you desire by adjusting the number of output devices, rail voltage and bias. AC current gain also affects peak output.
Although no boards are available, you can scale up the A75 a bit to meet your power goals and require a little less heat sink because of the push pull output stage. I run mine at ~58V output rails and 65V front end biased to around 45W class A. The articles at PassDIY include artwork that you can transfer to make the boards yourself. The difference between 100W and 75W is a barely noticeable 1.2 dB.
Take a look at the X100 backengineered thread for another possibility that would require you to make your own boards. This circuit would be easier to build on perf board than the A75.
If you can tear your friend away from pure class A, consider a Leach amp. With enough heat sinking you can get a significant area of class A operation and reserve power when needed. Tryonziess ran a group buy and may have boards left. There are other options in that power range, take a look through the forums.
As I mentioned in your other thread, the AJ-x on Peter Daniel's boards can be scaled to nearly any power you desire by adjusting the number of output devices, rail voltage and bias. AC current gain also affects peak output.
Although no boards are available, you can scale up the A75 a bit to meet your power goals and require a little less heat sink because of the push pull output stage. I run mine at ~58V output rails and 65V front end biased to around 45W class A. The articles at PassDIY include artwork that you can transfer to make the boards yourself. The difference between 100W and 75W is a barely noticeable 1.2 dB.
Take a look at the X100 backengineered thread for another possibility that would require you to make your own boards. This circuit would be easier to build on perf board than the A75.
If you can tear your friend away from pure class A, consider a Leach amp. With enough heat sinking you can get a significant area of class A operation and reserve power when needed. Tryonziess ran a group buy and may have boards left. There are other options in that power range, take a look through the forums.
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It remains a fact, that real class A amps of such magnitude, will turn rather expensive and fairly big.
However, if you insist to do a class A amp of 100W, I would recommend you take a look at the AX designs, as they run somewhat more efficient, and still offers most of what a real class A amp does.
Forced cooling does indeed sound like the reasonable solution, unless you feel like having a 50kg monoblock.
Magura 🙂
However, if you insist to do a class A amp of 100W, I would recommend you take a look at the AX designs, as they run somewhat more efficient, and still offers most of what a real class A amp does.
Forced cooling does indeed sound like the reasonable solution, unless you feel like having a 50kg monoblock.
Magura 🙂
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