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LSDJ Pitch Control – Interview with gwEm

I was cruising Facebook the other day and stumbled across 2xAA’s video of a pitch control that stepped neatly instead of speeding or slowing an ungodly amount. Mind blown! Asking 2xAA about it, gwEm was the creator and it had existed a long time. Naturally, I wanted to know more about, because presumably you all want to know more about it. So I asked him. With my brain words.

MT: Hallo! Thanks for agreeing to do an interview.

g: Hi Mike! No problem, I thought it would be fun.

First off. I was pretty stoked to see this in action. People have been talking about such a thing for a long time. Then to hear you have built it back in 2003 blew my mind a bit! How did you come to the conclusion to build one and what was the catalyst? Who was involved?

When I first got started with electronic music it was as a drum’n’bass DJ using 12″ vinyls. I wanted a way of mixing in my own 8bit effects into the set, the Gameboy was a nice a portable platform.

Previously I’d designed a similar device for MIDI and Roland Sync24. I’d also done a basic LSDJ MIDI interface. I could see it would be pretty easy to combine and simplify the two projects and get what I wanted.

I did all the work on it myself and used the lab equipment at the University where I was studying.


How did you go about building the device and what experience do you have in electronics?

Johan Kotlinski, the creator of LSDJ, was a mate of mine and had already explained the tempo protocol used over the gamelink cable for LSDJ. Since it was very simple – just a constant stream of zeros I just needed a clock with variable rate. After doing some maths, I put together a basic 555 timer circuit with coarse and fine adjustments to make it possible to get a wide range of tempos and precise adjustment. If you’ve ever tried beat matching a drum machine with a tempo control you’ll know its tricky. Once I had the prototype built from veroboard I tweaked the values of some components to improve the usability a bit.

I have two degrees in electronics – a Masters and a PhD, plus my day job is the leader of a microchip design team.

Have you used this in any specific tracks?

Yes, but none of them have been released. In fact I sold much of my Gameboy rig to concentrate on my Atari ST projects. I used it in a few live performances in 2003/2004, including the one where I met Malcolm McLaren(!).

How much roughly would it cost to build one myself, on estimate?

Always in these projects the most expensive parts are the case and the knobs. If you can improvise these yourself then you can really save money. If not, all the components are available in Maplins or eBay. You can build one for less than £20. Getting the 6 wire gamelink cable can be a pain in the arse.

Are you interested in making a revamped one?

Yes, I’d like to add switches for push and pull similar to a CDJ. It should be very simple to do. They aren’t strictly needed for beat matching, but they would make things alot easier.   

Instructions for the LSDJ Pitch Control are here.

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