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Old 18th December 2008, 04:06 PM   #2271
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During idle, all current will flow through the 2 output devices, 2 Amps times 48Vpp is 96 Watts dissipation.
At the peak of class A operation, your 2 Amps times 2 will flow only through 1 power mosfet.
With 20V out, Vds is only 4 volts, 4 volts times 4 amps is only 16 watt dissipation.

Biased at 2A, the die of the MOSFETs will be at 120C if you keep the heatsinks at 50C, chance of popping an output device will be 8 times higher.
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Old 18th December 2008, 04:09 PM   #2272
massimo is offline massimo  Italy
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Class A amps are different from Class AB ones. The latter become hotter as you play louder (and you increase the bias), while a Class A amp draw a constant current that can be turned into music or heat. Thus, if you play music, part of the energy goes to the speakers not generating heat.
We can then say: the louder you play, the cooler the amp stays
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Old 18th December 2008, 04:20 PM   #2273
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Quote:
Originally posted by jacco vermeulen
During idle, all current will flow through the 2 output devices, 2 Amps times 48Vpp is 96 Watts dissipation.
At the peak of class A operation, your 2 Amps times 2 will flow only through 1 power mosfet.
With 20V out, Vds is only 4 volts, 4 volts times 4 amps is only 16 watt dissipation.

Biased at 2A, the die of the MOSFETs will be at 120C if you keep the heatsinks at 50C, chance of popping an output device will be 8 times higher.

Quote:
Originally posted by massimo
Class A amps are different from Class AB ones. The latter become hotter as you play louder (and you increase the bias), while a Class A amp draw a constant current that can be turned into music or heat. Thus, if you play music, part of the energy goes to the speakers not generating heat.
We can then say: the louder you play, the cooler the amp stays

I learned something today. Sweet.
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Old 18th December 2008, 04:23 PM   #2274
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by jacco vermeulen
During idle, all current will flow through the 2 output devices,
Sounds just like a shuntreg

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Old 18th December 2008, 04:52 PM   #2275
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If you put it like that : What is the difference between a Single-Ended amp with a CCS and a Shunt regulator ?
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Old 18th December 2008, 05:08 PM   #2276
massimo is offline massimo  Italy
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Quote:
Originally posted by jacco vermeulen
If you put it like that : What is the difference between a Single-Ended amp with a CCS and a Shunt regulator ?
none
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Old 18th December 2008, 05:11 PM   #2277
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by jacco vermeulen
If you put it like that : What is the difference between a Single-Ended amp with a CCS and a Shunt regulator ?
The shunt reg will sink current as well as supply....



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Old 18th December 2008, 05:23 PM   #2278
labjr is offline labjr  United States
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Shipping is quite a lot to the USA i think. There is someone on headfi who knows of a US retailer, i will contact them and then get back to you.
Thanks I would appreciate that.
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Old 19th December 2008, 05:20 PM   #2279
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Default Heat Sinks and Heat Stinks

I can not find a proper heat sink for the F5
Will someone point me to the rightplace to orde?

Thanks
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Old 19th December 2008, 08:34 PM   #2280
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conrad heatsinks
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