C1 for the ESP P68

[leander]

what should be input capacitor C1 for the ESP P68 ?



The artlicle says :

"The input is via a 4.7uF bipolar cap, as this provides lots of capacitance in a small size. Because of the impedance, little or no degradation of sound will be apparent. A polyester cap may be used if you prefer - 1uF with the nominal 22k input impedance will give a -3dB frequency of 7.2Hz, which is quite low enough for any sub."

And if you observe clearly C1 on elliott`s pcb, it seems to be a small electrolytic.

[tool49]

Yes, you can use a bi polar electrolytic. For sub duties, you shouldn't hear any difference but If you prefer, you can use polypropylene or polyester... It's just a matter of fitting them in the space allowed.

Hope this helps!
Sébastien

[leander]

I found a small 1uF 63v polyester, would I be able to work with this?

[tool49]

Most definitely. Your cut off frequency will be a little higher than with a 4.7uF, but not significantly.

Sébastien

[AndrewT]

Hi,
1uF & 22k would be ok for a normal wideband speaker that has started to roll off from 50Hz to 60Hz.
For a sub amp you should be aiming for at least an octave or preferably two octaves lower.

I recomend you try 4u7F or even 6u8F with 22k. Otherwise you will be crippling the sub bass unit you are trying.

[leander]

Can I parallel 4 of these 1uF ?

[amplifierguru]

Hi Leander,

best do the maths. If your sub cut-off is at 30Hz then a 7.5Hz C1 rolloff will knock 1/4 dB more off it! Pretty small - 1/4 dB in 3.

Cheers,
Greg