Looking for a small Amp to run a sub off my ryobi radio.

First off, yes it's Friday, but this isn't completely a joke. I have a ryobi radio that blew the speaker and decided to modify it to work rather than buy a new one. Had an old JBL speaker to hook it up to, and we pulled a janky Alpine Type E sub out of the drift car. Currently that sub is wired straight inline, so looking for a small Amp I could place inline. Any suggestions?

I have usb or 3 prong power options.

 

and you have ryobi batteries...

what cost and size are you looking for?

dedicated sub duties, or full range?

after building two different tool box sound systems to run off milwaukee batteries, i think i can help

 

Dedicated to just the sub. Something cheap, just enough to drive the thing above regular speaker level, but maybe with a filter built in to prevent clipping. Something in the realm of $30 or less ideally. Not looking to run a full 1000w Amp or something.
The Bluetooth portion and regular speaker portion runs on the batteries, but it would drain it to tie the sub to those. But you're the resident expert sounds like. The tool box it's on has a power strip built in with the standard 3 prong and 12v usb.

 

$30 is going to be tough for the power adapter needed.

there's this amp board for $19 that includes the tone controls for a subwoofer

$20 100W Digital Amplifier Board Subwoofer Amp Module for DIY Speaker 12 to 24V Power Supply, Multi Functional with Preamplifier, Bass Crossover

https://www.amazon.com/Vbestlife-Amplifier-Subwoofer-Digital-Speakers/dp/B0B2P8LWWV

but then the budget gets blown on the power supply to get full power, which is going to be $16

$21 DC 24V 5A Power Supply Adapter 120W AC Adapter 100-240V 50-60Hz to DC 24 Volt 5 Amp Cord with 5.5mm x 2.5mm Barrel Plug, 24VDC Transformer

https://www.amazon.com/Adapter-100-240V-50-60Hz-Covnerter-Transformer/dp/B0BJZXFZ2H

alternatively, a 12v power adapter is only $10. it'll still work, just output less overall power

$10 12V 5A Power Supply, Waysse Power Supply Adapter, AC DC Converter 100-220V to 12 Volt 5 Amp Transformer 5.5x2.1mm Plug for LED Strip Light DVR NVR Security Cameras System CCTV Accessories

https://www.amazon.com/Converter-100-220V-Transformer-5-5x2-1mm-Accessories/dp/B08C594VNP?th=1

and a note-- all the amp boards in this price range are all for accepting line level, not speaker level inputs. the ryobi 'should' be outputting a low enough voltage to be considered line level, but it's one of those 'don't know until you try' things. just turn the volume down on the ryobi until it doesn't crackle on the sub. should still be plenty loud enough in the majority of cases.

for an 'all out' setup with speaker level inputs, you'll either need an adapter like this to use the above stuff,

$6 pinflaw Pack-2 Car Subwoofer Modified High to Low Frequency Audio Converter, CD Player Audio Wiring Output, Speaker Output to RCA Line Control Audio Signal Adapter, Universal for Cars (Transparent)

https://www.amazon.com/pinflaw-Subwoofer-Frequency-Converter-Transparent/dp/B0D5QGJXD4
or a subwoofer amp like this, that must be used with the 12v power adapter, but has speaker level inputs

$25 High Power AMP Board, Car Audio Amplifier Board 120W 12V Pure Full Tone Bass Subwoofer Core Auto Stereo Speaker AMP

https://www.amazon.com/Amplifier-Aluminum-Subwoofer-Stereo-Speaker/dp/B0C6NK1M5H

 

This is on sale and includes a power supply, but js a bit over budget

https://www.parts-express.com/Lepai...put-with-12-VDC-3A-120-VAC-Power-Supp-319-308

 

I've had good luck with random class D amps from Amazon, have a few that run on 12-24vdc that are bridgeable, most will do around 150-200w, battery will probably be abysmal though. There's a reason portable radios use small drivers and really well designed chambers and ports to maximize bass rather than huge drivers.

 

Looks like whatever I do I'll have to splice an aux cable into the radio output. Right now I'm just running red and black out from the original speaker line.

68w, and I wish it showed the back of the unit.
Looks like they accept speaker level since the add-on item is RCA to Line, without diving into the details.

What about this?

$56 Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer

https://www.amazon.com/Subwoofer-Amplifier-Receiver-Integrated-Audio/dp/B07942M4MC/
Looks to be all in one and RCA input, so I could splice one cable out, tie it into the ryobi, then run mono input to the amp. Since the ryobi radio is only Mono technically, only one speaker, then I won't need both RCAs correct? Or should I splice both together and run it that way? budget tossed aside since I'd rather not piecemeal if I don't have to.

 

yes, that fosi audio amp would work. the only concern is going to be the input level. the radio 'should' output low enough that it's not a problem, but there's no knowing until you try.

you'll only need to connect one of the rca's to get the audio into it. it should be a summing amp, meaning that it takes R+L audio signals and adds them to each other for a single output.

 

Ordered. Will update with results! Thanks for the help fellas.

 

Works! Not super loud, but it's better than it was.