AKSA's Lender Preamp with 40Vpp Output

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Thanks X,

I was wondering about the 10uF. No problem with the fit. After reading the discussion you had about the capacitance value of between 2.2uF and 4.7uFwith jwjarch as compared to the 10uF, and the discussion about "too much capacitance", and the test you performed with the 10uF cap and the 1uF ChiFi caps, I thought I would ask the question above.

If the 10uF is not the one, I can order up a couple of 4.7 uF caps or order some of the larger boutique caps the boys are using and just wait to install them.

What is best ?

MM
 
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The input cap has 43k (R1 + R2) of resistance to ground in the right side and 100k (R13) to the left side. Assuming Parallel resistors equation (since draining from both sides but technically I’m not sure this is right) - says this is equivalent to 30kohms. If we use the formula for calculating the -3dB corner frequency fc = 1/(2pi x R x C) and we would like to set fc at least 2 octaves below low frequency of interest to ensure its flat. Assuming we want flat to 20Hz, 2 octaves below is 5Hz. Set fc = 5 Hz, R=30kohms and now solve for C.

C=1/(2pi x R x fc) = 1/(6.28 x 30k ohms x 5Hz) = 1.07uF

So 1uF should be enough. 10uF is overkill then. 2.2uF should be more than enough for flat to 10Hz and 10uF good to 2.5Hz.

So now you can judge for yourself what you think you might need.

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Had I another power amplifier, I would do such a test. But alas, my maker fu is weak, and I have, at present, only my MoFo. The M2X and ACAMini await my attention.

To complete the circle, my M2X is operational now, and plays just fine. Even at levels well into the VERY LOUD range. ;)
Thanks to @xrk971 and @Vunce for helping to determine that my MoFo was just not up to the task.

Kind regards,
Drew