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Old 29th January 2006, 08:11 AM   #1
quyda is offline quyda  Viet Nam
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Join Date: Feb 2005
Location: Hanoi
Default I need calculation formula for Aleph

Hi guys,
I'm kinda newbie here, and I'm planning to build a 30W/ch Aleph.
A have looked at the schematic from http://www.kk-pcb.com/
To my understand, The Aleph share the same topology and the different if Voltage per Rail, and Bias Current.
But I dont know how to
1. Calculate Bias current from Schematic
2. Does number of Mosfet matter? If I use IRFP250 (=2xIRF240) can I use more IRFP250 share the heat disspation per fet?
3. How Voltage/Bias Current affect DC offset?
4. Can I Built Aleph 5 and reduce Bias Current 30W/Ch

Any comment/suggest would be highly welcome
Cheers
Quyda
Ps. My Speakers are Yamaha NS-200M 6Ohm, 100W, 90dB.
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Old 29th January 2006, 09:09 AM   #2
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Hi,

1. you can calculate the max. bias assuming that 0,5-0,6 volts is over the source resistors. Then I = V/R times the amount of fets.
2. not really, as long as the dissipation per fet is not too high
3. not
4. yes you could but then you could also build an Aleph 3 or 30 wich has a lower rail voltage (25 instead of 34 volts)

William
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Old 29th January 2006, 09:39 AM   #3
quyda is offline quyda  Viet Nam
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Join Date: Feb 2005
Location: Hanoi
Sorry for my ignorance but can you give me an easy example on a few Aleph. And if I want to tweak my Amp a bit, which component so I look?
If I build a Aleph 3 using IRF250, can I still use 4 Mosfet just like IRF244 or should I use 2 as Mr Pass said?

Cheers
Quyda
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