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Old 31st January 2009, 05:25 PM   #1
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Default On the verge: help with Aleph 30.

I've gotten my "dumbest" question answered. Now I need some help with some simply "dumb" questions.

I've spent a couple of weeks reading every post in the "Mini_A PCB" thread and most of the posts in other threads referenced in that thread, pored over multiple schematics, including Algar_emi's very helpful one, and am ready to order parts.

Attached below is the Mini_A schematic.

I'd like to build a pair of Aleph 30 monos with Brian GT's latest boards based on this schematic, and start out with both amps running at maximum bias, so I'll omit R13. I'd like to substitute a trimmer at R12 so that I can adjust AC gain, and another one at R8 so that I can adjust DC offset. What value trimmers should I use at R8 and R12?

I'll use Brian's PS boards with 20-0-20 trafos and 99,000uF per rail and will not permanently install the CRC resistors until I can run the completed amps under load and adjust their resistance to achieve 25 volt rails. What value CRC resistors should I start with in the power supply (I can't get PSU Designer to work correctly on my 64 bit desktop)?

Thanks for your help.

George
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File Type: pdf miniasch.pdf (22.4 KB, 54 views)
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Old 31st January 2009, 06:32 PM   #2
Zen Mod is offline Zen Mod  Serbia
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make :

R8 - 150E +100E pot - in series

R12 - 470E + 1k pot - in series

R28=R27=R23=R24=R25=R26 = 0R33, so - you'll have around 2A Iq

if you want more - decrease them to 0R27

Iq~ Ube/R28 (where Ube is 0V65 - for Q5)

CRC - 0R47/5W WW is good enough
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Old 31st January 2009, 07:14 PM   #3
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Default Thank you, ZM. Ummm...

Could you take a moment more for some basic ee education? Namely, the meaning of "E" in reference to a pot?

George
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Old 31st January 2009, 07:37 PM   #4
Zen Mod is offline Zen Mod  Serbia
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Default Re: Thank you, ZM. Ummm...

Quote:
Originally posted by Colescuttle
Could you take a moment more for some basic ee education? Namely, the meaning of "E" in reference to a pot?

George

E=R=V/A=Ohm

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Old 31st January 2009, 07:46 PM   #5
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Default Thanks, again!

George
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Old 31st January 2009, 08:07 PM   #6
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Default Re: Re: Thank you, ZM. Ummm...

Quote:
Originally posted by Zen Mod



E=R=V/A=Ohm

V/A = voltamps?

or

V/A = volts divided by amps?
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Old 31st January 2009, 08:20 PM   #7
Zen Mod is offline Zen Mod  Serbia
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Default kwayzee yank

Quote:
Originally posted by mpmarino


V/A = voltamps?

or

V/A = volts divided by amps?

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Old 1st February 2009, 03:02 AM   #8
eyoung is offline eyoung  United States
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Hola again,

Check out this web site or google ohm's law
http://www.kpsec.freeuk.com/ohmslaw.htm ...


Regards, E
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