Cary SLP-05 Output Capacitor Question

Why are you asking anyway? I don't know what your question really is as I am totally (utterly as will be apparent) uniformed, but what does the schematic show? Or is that in fact your question?

I have confirmed that the these are the output caps. Cary does not provide the schematic so I hoped someone else would know the specifics. I meant to say that I had replaced the stock cap combination with the single Mundorf cap with good results. I was very surprised that the conventional formula upon which the V-Cap calculator is based on resulted in such a great reduction in the outlet cap's value. This small a cap means I can afford to use CUTF caps which must be the intent of the calculator. Hopefully someone who has replaced a much larger cap with a much smaller one can share their experience.

The only thing you are potentially doing is raising the frequency of the -3dB down point in the low end.

I was very surprised that the conventional formula upon which the V-Cap calculator is based on resulted in such a great reduction in the outlet cap's value. This small a cap means I can afford to use CUTF caps which must be the intent of the calculator. Hopefully someone who has replaced a much larger cap with a much smaller one can share their experience.

The experience of others won't be relevant unless the load impedance they were driving approaches the 1 Megohm input impedance of your active crossover, which is an exceptionally high value. As you probably realize, that figure is why the calculator indicates 0.08 uf as being acceptable. A more typical load impedance of 50K, which is 20 times less, would raise the 0.08 uf by a factor of 20, to about 1.6 uf for the same 2 Hz corner frequency.

Good luck with your project! Regards,
-- Al

Thank you for the responses. I did want to clarify for any XM126 owners that Phil has indicated that the input impedence for the XM126 is 500K Ohms and not 1M. This is still a very useful value if one is attempting to upgrade capacitors efficiently.

M, understand that all the tubed circuits with coupling caps that I've seen have a shunt resistor following the cap, and that value is in parallel with the input impedance of the device the preamp's driving. Be careful to include that value in your calcs, and if you value high-quality low bass, don't let the filter point get above 2Hz.
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You can assume that the shunt value Jeffreybehr mentions to be around 1Mohm, if you can't find it. This is used to prevent the output cap from having a charge on it that could damage an amplifier input.

That would make your total driving impedance to be only 500K, meaning that you will want about 0.2uf. Knowing that shunt value could be important.