DIY: Homemade sound system with AUX input

I decided it was time to replace the old, barely working cassette radio and speakers with something a bit more modern and with AUX / iPod input. Here’s my very cheap DIY solution!

First, I removed the old radio and speakers to see what I was working with. The dealer-equipped cassette radio would still occasionally play AM stations, but had no FM capabilities. Though I own CDs, I haven’t touched a cassette tape since my 9-year-old Walkman days and decided I’d try to find something that worked with an aux cable. The project’s main goal (apart from playing music, obviously) was to stay within my £50 budget.


100x100cm, 5mm thick piece of wood.
A bunch of small bolts, washers and nuts.
10A-capable wiring, red and black.
1x Pioneer TS-G1732i 17 cm 240 W 2 Way Coaxial Speaker System (£25.99 on Amazon UK)
1x LEPY 2024A Plus Amplifier – Silver/Black (snatched it for £9.99 on Amazon UK)
1x male RCA connector (£5.40 on Amazon UK)
An old aux cable

Total spent: £59.95.

Alright, so I exceeded my budget just a bit. I got lucky with the LEPY desktop amplifier as it was on sale at 20% off it’s regular price. I also already had a collection of bolts, nuts, and all the tools required. The reason I went with the LEPY as opposed to a normal head unit is mostly cost, but also the ease of mounting and wiring it, and eventually removing it. As an added bonus, the Lepy amp has a built-in power switch so I don’t risk the battery draining. The speakers hook straight into the back of the unit and it has a female RCA connector for power. My plan was to create a small box that sits under the dash, housing both the speakers and amplifier while leaving space for additional switches and a USB charging port. Note that this is supposed to be a short-term, rough design that I can properly replace in the future!

The Build

Testing the cheap eBay amplifier

First I wired it all up to make sure my plan would work. I took a small length of wire, screwed it into one of the male RCA connectors (the connectors I linked above have a screw to hold the wire in place) and took a second length of wire to act as the ground, which I then also screwed in. The speakers come with a couple of wires each, clearly labelled positive and negative. These simply clip right into the back of the amplifier. Finally, I made a tight loop with each end of the power cable and hooked it up to a car battery. I flipped the power switch on the amp to the “on” position and waited… no sparking or smoking. So far so good! I tested the system with my iPod and the aux cable, blasting tunes as loud as the unit could handle. It has a built-in overload protection, cutting music briefly when the bass kicked in at max volume. I was pleasantly surprised by the amplifier. The music was loud and clear and easily tune-able thanks to the bass and treble dials. It would do nicely in my loud and rattly Sprite.

All the panels for the radio box.

All the panels for the radio box.

Next up was the wooden box. I measured the interior space under the dashboard. I wasn’t too comfortable placing the speaker’s powerful magnets right next to the cheap and unprotected amp, though it didn’t seem to compromise anything in the short term. Looking back at it now, the box is much too big, with the speakers’ magnets taking up the majority of the upper half and the lower half being more or less unused. Either way, I cut the wood, drilled some holes to fit the panels together with L-brackets and came up with an odd combination of flattened brackets to fit the amp.

More-or-less complete box. Time to disassemble and paint!

More-or-less complete box. Time to disassemble and paint!

The speaker box came with a handy cutout that I could use as a template for drilling holes. I decided I’d be fine with the mounting rings poking out a little, as space between the box and my gear stick was getting tight. I threw it all together, added a Marine 12V USB charging port (£5.99 on Amazon UK) and a switch to activate it as well as a switch for my blower fan – the original twist-knob stopped working at some point when the fan seized… that’s a story for another time.

Radio box mounted in the car...almost.

Radio box mounted in the car…almost.

With everything connected and working, I gave it a lick of black paint and mounted it to the dashboard with the back panel resting on the padded panel under the dash. There were oddly-sized holes on the bottom lip of the dash, almost as if they planned for this! Truth be told I had no idea how I’d mount it until now…

The wiring was simple as I had previously installed a marine-style fuse block next to my battery. I’ll definitely have to revisit that installation as well in the future.

It may not be pretty, but it works for now!

As always, thanks for reading!


By | 2018-10-06T15:04:48+01:00 April 2nd, 2017|DIY / Tech Tips|0 Comments

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