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Low frequency amp? Answered

For a future project (blue barrel infra sub woofer with ducted fan) I'm already looking for parts. I see most amplifiers and amp chips (like the TDA7294) have a frequency response usually 20 - 20,000 Hz. But I'm interested in a range from 0- ca 40 Hz. As far as I understand, the low cutoff is to protect the driver (speaker).
Would it be possible to circumvent the low cutoff, or would I have to build from scratch? (I'm thinking in a 70 - 150 W RMS range).


Look for amps with dual supply rails, or ones you can bridge. Higher pass amps "cheat" by coupling the output with capacitors, what you want would need very expensive caps.

Given your location, I'd recommend a Velleman kit - their
I've used it for my own sub-woofer. I can't buy the parts for the price Velleman put a kit together for.


You can do as steveastrouk suggests, or you can try to build your own Losmandy Amplifier. I was recently introduced to this topology and am amazed at the flatness of the response. It is flat from 0 to 70kHz. Here is a link to a low to medium powered version: www.postimage.org/image.php. You could work with more voltage, if the opamp and output transistors can handle it, and get more power out of the circuit.

Also, if you go with a bridge configuration, you'll get approximately 4 times the power. Just make sure your power supply can handle it.