change voltage rails Aleph2 J


2019-09-26 1:11 pm
Hi everyone,

Building the Aleph2 J from the attached schematic, i got a question about front end component values. Since my speakers have 3 low points of 3 Ohms and a max of 8 Ohms, i like to match the amp to this impedance.

Using the excel sheet, turned out a rail voltage of about 37V is fine with bias of around 0,67A the power output should be like 140W at 4Ohms. The rig runs a little slower, wont need that much power and produces less heat (i hope:)
the junction temp was fine too. (according excell sheet around 100-110C)

Do i have to change any values of components in the front end to compensate for this lower voltage rails? When yes, which parts?

(see schematic)

Thanks a bunch!

ps im designing the PCB's they are almost done and i might have a few spares if anyone is interested?


  • A2-Jfet-Inp-A14-schema.pdf
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2019-09-26 1:11 pm
Hi Zen mod en Vitalica,

I searched on the schematic and found this original one, which has the C9 on the output line? Now im confused as you can see.
Also there aint a zener over the transistor in the original.

Can you explain please what difference it does do here?



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2019-09-26 1:11 pm
Cleaned up the board, according updated schematic. when all components are in house im gonna final check drillholes and dimensions so no surprises when soldering.

Im gonna open a build thread when time is there.
Thanks again for your help sofar!



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