Circuit Bending a Boss DR-55

My father in law gave me an old classic Boss DR-55 analogue drum machine a while back, but it doesn’t have any trigger inputs, or MIDI control, or clockability. You can’t tweak the individual drum sounds either really. So… I decided to bend it a bit to make it more usable.

I started this a few months ago, but kinda messed it up out of inexperience, so put it away in a box in a cupboard and finally fixed it up over the past few days.

Specifically I put in bass drum mods - pitch and decay, though they both intermingle a fair bit. I also put in trigger points for the three main sounds. Anyway, have a watch if that’s the kinda thing that you are interested in. If you have one and need help I can give you my very basic knowledge ha.

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Very cool. Despite its rubbish kick sound, I’m quite fond of the DR-55 and just spent a couple of days laboriously sampling and programming a track with one. It would have been much more fun to do it this way!

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Hey! I‘m just in the process of modding my DR 55 and can’t find good info on the trigger in mods. Would you care to share your knowledge? :slight_smile:

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Hey there,

I used the following guides:

http://machines.hyperreal.org/manufacturers/Boss/DR-55/mods/

https://electro-music.com/forum/topic-55808.html

The trigger mod input is really easy. You basically look for the three wires for the kick etc which are clearly marked, and then inject a single into them. The hi hat was trickier so I gave up :slight_smile:

Best of luck!!

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Thanks! Singles as in single 1/8“ jack sockets? And just connect the positive to the respective wire and the ground to… ground?
I found these pages as well, but the only one suggesting individual trigger inputs was a bit vague. Much appreciated!

Sorry, auto-correct fail. Signal, not single :slight_smile: You can use whatever jacks. I used 1/8" jack sockets in and wired them up as you described. Positive to the wire. I just soldered them right on. Then ground them to… err somewhere on the board that I can’t remember :smiley:

I can’t find the page where I found the trigger info… or maybe I made it up. Anyway, the wires are detailed on the schematic and easy to find, but I think they are the ones in the lower left of the below picture - the three that run horizontally

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Ah! Now that i can work with :slight_smile:
It‘s described on the ‘machines.hyperreal’ page. But it sounds more like a hypothetical experiment with unknown consequences on there… thanks a bunch! Will try :crossed_fingers:

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Somewhat unrelated, but it’s heartening to see that Hyperreal is still online after nearly three decades.

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