Original LDB

Original LDB

I first came across Delptronics when he announced he was making a euro modular of his DIY analogue drum machine, the Little Drummer Boy. There is a ton of information on Mickey Delps' site about how he designed the circuits for the drum sounds and it's a fascinating and informative read.

Anyway, I quite fancied a go at building the desktop version but the original format and case looked awkwardly small (no offence, Mickey!). Luckily you can buy the DIY kit without the enclosure so once I'd built the circuit and got it working I set about trying to put together a bigger box in which to house it (inspired by Mickey's own Giant Little Drummer Boy which is an awesome piece of work)

I found a suitable off-the-shelf box in which to put everything and found some funky-looking momentary switches on Ebay which I thought would suit the job really well.

In the second picture you can see I've drilled the case for the inputs and outputs and I drilled the front plate that came with the enclosure, just so that I could wire everything up and test it.

I then set about designing a completely new front plate (yes, out of acrylic!) and this is what I came up with.


I ended up ditching the original momentary switches for those really nice low-profile ones. Because the new switches are PCB mount I had to construct a couple of sub-boards to mount them on which I made out of stripboard and some interesting wiring. Hey, if it works don't knock it.

The extra row of knobs at the top were a result of me experimenting with the board. There's a ton of information on Mickey's site, as I said, so it was easy to desolder parts of the circuit and play around with the synthesis. I was going to add all sorts of controls to modify the drums sounds but I ran out of panel space so I limited it to just 'volume' of the individual drum circuits. I say 'volume' because due to the simple nature of the mods, essentially it's just replacing the limiting resistors before the individual sounds hit the mixing opamp. As such it's ridiculously easy to overload and saturate the sound. It's quite fun though! Excuse the quality, it was just recorded with my phone.

DIY electronics Delptronics

Published on by Neil Baldwin.