Best way to amplify ultrasonic generator?

Thread Starter

tccalvin

Joined Aug 15, 2021
5
I currently use a Kemo M048N Ultrasonic Generator coupled with a 150W Piezo tweeter to keep pests out of my garden.

I need to relocate this meaning it will be further from the end of my garden and it would be useful if I could amplify the noise.

I was initially looking to use a small car amplifier but I'm not certain if this will work?

Any help would be much appreciated.
 

Audioguru again

Joined Oct 21, 2019
3,818
Articles in Google say, "There is no credible scientific evidence that suggests ultrasonic pest repellers work."
Other articles say if an ultrasonic device repells a pest then the results are only temporary until soon the pest becomes accustomed to the sound that causes it no harm.

A piezo tweeter has a high impedance but a car amplifier is designed to drive a very low impedance speaker.
Then the piezo tweeter will produce the same or less output level with a car amplifier as it does with the Kemo ultrasonic generator.

There is a cheap 150W piezo tweeter sold on ebay. Its important technical details are its size, weight and color.
Gullible people buy it and since they cannot hear it then they think it produces ultrasonics but it does not.

Most car amplifiers claim 200W (200 Whats). But their real output is only 14 watts per channel.
 

Audioguru again

Joined Oct 21, 2019
3,818
Many car amplifiers do not work at ultrasonic frequencies.
An RF amplifier will do nothing at an ultrasonic frequency. It works with frequencies that are hundreds or thousands of times higher than ultrasonics.
 

Thread Starter

tccalvin

Joined Aug 15, 2021
5
@tccalvin , Sorry I can't help with your problem but I'm interested to know what kind of pests are you trying to keep out?
Rats and mice mainly. We had infestations of mice in two different outbuildings a few years ago.

The above has worked incredibly well and for a long period of time.
 

Thread Starter

tccalvin

Joined Aug 15, 2021
5
Articles in Google say, "There is no credible scientific evidence that suggests ultrasonic pest repellers work."

Other articles say if an ultrasonic device repells a pest then the results are only temporary until soon the pest becomes accustomed to the sound that causes it no harm.

There is a cheap 150W piezo tweeter sold on ebay. Its important technical details are its size, weight and color.

Gullible people buy it and since they cannot hear it then they think it produces ultrasonics but it does not.
This solution has performed above and beyond my expectations and continuously for years, hence the desire to keep it in place (not to mention how cheap the components were). The tweeter is a genuine item and I've tested this with a scope.

Thanks for a reminder of the good old fashioned chip on the shoulder forum user though, I haven't encountered anyone like yourself in years. I did find a video of exactly what I was looking for though if it helps anyone else:

 

Audioguru again

Joined Oct 21, 2019
3,818
The video showed two car amplifiers. The Pyle 2200 one used as a test is rated at 700W maximum per channel or 80W RMS into 4 ohms per channel.
Distortion at the 80W was not mentioned but the standard is 10% of clipping which would be 64W at a fairly low distortion of the fundamental frequency.
Then the voltage across the tweeter is only 16V RMS. If the tweeters are 8 ohms then the power in each one is 32W.

The video showed two different tweeter models. One of them has specs that say that its maximum frequency is 20kHz then it will not produce ultrasonics.

Maybe your mice did not like the smell of your amplifier heating all the time.
 

Thread Starter

tccalvin

Joined Aug 15, 2021
5
The video showed two car amplifiers. The Pyle 2200 one used as a test is rated at 700W maximum per channel or 80W RMS into 4 ohms per channel.
Distortion at the 80W was not mentioned but the standard is 10% of clipping which would be 64W at a fairly low distortion of the fundamental frequency.
Then the voltage across the tweeter is only 16V RMS. If the tweeters are 8 ohms then the power in each one is 32W.

The video showed two different tweeter models. One of them has specs that say that its maximum frequency is 20kHz then it will not produce ultrasonics.

Maybe your mice did not like the smell of your amplifier heating all the time.
Um, I'm not sure if you read the OP but I was asking for information regarding amplification, that video isn't mine...

Are you okay?
 

Audioguru again

Joined Oct 21, 2019
3,818
Tccalvin, you are this Thread Starter. You posted the video.
You asked about an amplifier and I pointed out that the "700W" amplifier rating in the video is actually only 64W.
Your "300W" tweeter might survive only 27W.
 
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