A friend give to me it's 5.1 speaker system subwoofer.
The brand it's Kevler. It has an integrated amplifier for a 5.1 speaker. The problem is that the amplifier does not work. I've checked a few things around but I did not find anything sensational. Also I don't have a subwoofer around to use.
So I decide to repurpose this as a single subwoofer system.
The speaker is rated 120watt, 6ohm.
I've buy a TPA3116D2 cheap board, it maybe does not even have a genuine chip, but for my purpose I will not investigate, I'm happy with that. I'm going to use a 24V supply. I've around one of 3A.
From figure 22 and 26 of TPA3116 datasheet I can only find Maximum Power Output in PBTL for Rl of 2ohm and 3ohm. My speaker is 6ohm.
So to estimate the consumption I've supposed a 50W max output, and a 85% efficiency. My estimation formula is Power/Efficiency/Vsupply, so 50/0.85/24 = 2.5A almost. My 3A supply should fit it.
I've add a passive third order passive low pass filter, it just uses a few resistors and capacitors. You can find the schematic at electroimc.com website (https://www.electroimc.com/en/doc/projects/audio/3_subwoofer_third_order_passive_low_pass_filter)
Then I've add a 230V switch and a volume control.
The result is a pretty good subwoofer I'm going to use in my gym environment.
Notes
- read risk disclaimer
- excuse my bad english