Feedback Cap in Aleph and Aleph J - diyAudio
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Old 12th November 2008, 06:15 AM   #1
Fox is offline Fox  Netherlands
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Default Feedback Cap in Aleph and Aleph J


Last night, I started comparing the schematic of the Aleph 5, which I made several years ago, and the Aleph J. Besides the obvious differences, I saw that the 220uF electrolytic cap in the feedback loop of the Aleph 5 was replaced bij a 1 uF film cap in the Aleph J. I have searched the forum but somehow failed to find an explanation why the cap is so big in the Aleph 5 and so small in the Aleph J. Perhaps you can offer me an explanation.


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Old 12th November 2008, 11:05 AM   #2
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the 220uF cap in the Aleph 2,3,4,5 is much bigger than needed for a flat frequency response. It was probably chosen to keep all three caps the same.
Another reason you can use a smaller value in the AlephJ is the higher values of the resistors and the lower input capacitance.

een ooievaar is geen konijn want zijn oren zijn te klein!
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Old 12th November 2008, 03:23 PM   #3
Fox is offline Fox  Netherlands
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Hi William,

Thanks for the explanation. I also figured out that a 33 uF cap should me more than enough to go straight down to 10 Hz. At least, that's what my simulator showed me. It appears that Nelson has a lot of 220uF caps on stock .


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