Speaker Filter

[SISKO]

So. i want to make a Speaker (8ohm) Filter with a freq conrner at 5k but instead of  placing an inductor in series, i want to place a low value cap in parallel.
Its a 50w tube amp.
Should i have any consideration in mind besides the voltage rating?

[George Giblet]

I'm assuming you want to filter the sound from the speaker?

> i want to place a low value cap in parallel.

It won't work.  Do do it.  You might cause you amplifier to oscillate at full output which could fry your speaker.

If you want to use a parallel cap you have to add a series resistance between the amp output and the speaker/cap.   The resistor will dissipate power and the output power to the speaker is effectively reduced.

[DDD]

Some amps can easily drive a speaker with 5uF cap in parallel, and some ones cannot. Begin with adding 4 to 8 Ohms resistor in series with the speaker\cap to protect your amp from possible trouble. Be thorough. If OK, reduce the resistor value to 2\4 Ohms, and so on.
Even if your amp will behave properly without the serial resistor at all, install at least 1 to 1,5 Ohms in series. Of course, you'll lose some Watts of the output power, but it's a reasonable price for the better sound,