I need to build a passive high-pass filter that has a cutoff frequency of 2-3 kHz. Sounds simple? It needs to pass between 10 and 20 W rms power at 20 kHz without overheating and going "bang". 

The purpose of this circuit is to supply AC power to a nichrome wire heating element avoiding n\*50 Hz amplifier noise due to mains electricity frequency. The rms voltage is below 20 V and the current is below 1 A.

In a previous attempt, I tried to build the circuit below, where R1 is the nichrome wire heater and C1 is two opposite 100 uF electrolytic capacitors in series (cathodes joined together):

[![enter image description here](https://i.stack.imgur.com/rUmvm.png)](https://i.stack.imgur.com/rUmvm.png)

This worked for about 10 seconds, then one of the capacitors exploded:

[![enter image description here](https://i.stack.imgur.com/6c3Qm.jpg)](https://i.stack.imgur.com/6c3Qm.jpg) 

My questions are:

* What do you think went wrong with my attempt? e.g. Was a 35 V capacitor rating not high enough, or was cooling needed?
* What would you suggest will give the circuit the best chance of working as intended.