Lots of us do. No stigma attached, it's just not a design question. (Cross-posted to s.e.basics)
The answer depends entirely on whether the amp itself is stable with a pathological load like that, and (assuming that it is) what its input is and what the characteristics of the cap are.
If the amp output is just sitting at zero volts, it isn't going to do anything dramatic to the cap. If it oscillates, or if you put in a large AC signal, and the cap is a smallish polarized electrolytic (as opposed to a nonpolarized one), the cap probably isn't long for this world, unless the amp dies or current-limits first.
The reactance of such a capacitor at (say) 10 kHz is
i.e. very nearly a short circuit. The equivalent series resistance (ESR) is probably more than that, so the cap looks like a very low resistance.
The net is that depending on the characteristics of the amp and what you put into it, your cap could be destroyed or could be completely unharmed.
Actual audio people will probably have a better handle on how your average 100W amp will respond to such abuse.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
** At very low audio frequencies, the 4700uF cap could be driven into reverse breakdown, then overheat and explode.
At higher frequencies, the amplifier would see the cap as a short circuit and behave accordingly - either by blowing fuses, rapidly overheating, hard current limiting or just turning itself off.
FYI:
If you ever need to test your car's air bags, driving into a solid brick wall at 50mph is one way.
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Based up the replies so far, I could use a bipolar cap (two electros back-to-back), as well as series resistance to ground to protect the amp. I am thinking 22 Ohms to be safe.
Or, connect a resistor from the positive terminal to ground as a parallel load.
If I need to use a polarised cap, then I assume a single-ended amp would work.
"Back to back" means inverse series connection, so that plus a series resistor would make a safe load for the amp at least. Whether it was safe for the caps would depend on their voltage and ripple current ratings.
So why do you want to do this?
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
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