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Old 20th August 2001, 08:36 AM   #1
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Hello.
I just built the Aleph3,the problem is that i have the half
of the bias current(1A total)at the three output Fet's.
How can i increase the bias current?
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Old 20th August 2001, 10:31 AM   #2
Koy is offline Koy  Czech Republic
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Bias can be adjusted by resistor -R113-( 47k originally). The higher value the higher current - at about 68k it should run on about 2,7A. I use in this position the trimpot.
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Old 20th August 2001, 12:17 PM   #3
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Koy.
How many fet u using per rail and what type?
Thank's.
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Old 20th August 2001, 12:54 PM   #4
Koy is offline Koy  Czech Republic
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I have Volksamp modification build - ie 3 MOSfet per rail, IRFP 244.
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Old 25th March 2002, 07:13 AM   #5
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Default Aleph 3 with 4 output devices

I have four matched IRFP240s and planing to build SOZ but after considering the cost I have changed my mind to Aleph 3. Since the Aleph 3 using 8 output devices, is it possible to use 4 output devices? It seems I must change the source resistor, but with how much resistant value?

Thank you for any response.

Yamin
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Old 28th March 2002, 02:44 PM   #6
BrianGT is offline BrianGT  United States
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I would assume that you could make the Aleph 3 with half as many output devices. If you look at Mark's Aleph 4 at:

Mark's Aleph 4

He used half as many output devices as the design called for, due to a mistake in the service manual, and it works great for him.

I am not sure exactly what values that you would want to use for resistors, but I would imagine that you would use half the resistance.

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Brian
gte619j@prism.gatech.edu
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Old 28th March 2002, 04:46 PM   #7
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Thanks Brian.
By the way, Mr. NP have answered my question. He said the value is 0.22 ohm, same as you suggested.

Regards,
Yamin
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