![]() Posted by Jon Risch ( B) on Augat 19:21:15 Note that due to the high impedance of the piezo, you can wire more in parallel with the circuit I just mentioned if you want to increase power handling. Doesn't work too well for higher power applications though. A 1st or 2nd order filter is needed before this lot though or the 8r resistor is going to have to sink huge amounts of power. To pad it down, a capacitor in series works ok, but the best thing to do IMO is put an 8r resistor in parallel with it as a sort of dummy load and then vary the power across the resistor/piezo combo with an L-pad, treating it like a normal tweeter. It will benefit from a 4r resistor in series though if you find it to be too gritty and harsh.the capacitive load of the piezo crystal doesn't play nice with some amp, forming a resonant circuit. The only reason you might want to use one is to protect the amp as 80khz+ frequencies can send it into oscillation.but modern amps have filters so you don't need this. ![]() Motorola piezos have an internal lightbulb and a thermal breaker in parallel for protection - when the breaker opens up, the power passes through the light bulb instead, limiting power as the filament heats.Ī 47r resistor in series won't do anything as the nominal impedance of that piezo is high.around 1000r. The £3 ebay jobbies are terrible little ear-melting things, and they're a nasty load to drive too. If you're going to use a piezo, I wouldn't advise using anything other than the Motorola/CTS ones as djk said.
0 Comments
Leave a Reply. |