[sdiy] Kenton TB-303 sockets schematic?

Richie Burnett rburnett at richieburnett.co.uk
Mon Apr 10 21:37:26 CEST 2023


The TB-303 that I got second-hand many years ago has a set of 3.5mm jack 
sockets along the back of the enclosure marked SLIDE, ACCENT, FILTER, GATE 
and CV.  I believe these are a mod for use with a Kenton MIDI-to-CV 
interface?

Does anyone know the details of how these sockets connect into the rest of 
the TB-303 schematic?  Last time I had the 303 open to replace the tact 
switches I noticed that there were various resistors and transistors inside 
bits of heat-shrink tubing soldered to the copper side of the PCB.  I'm 
trying to find a schematic of the connections for a couple of reasons:

1. I want to know how to fix them if a wire should fall off at some time in 
the future.
2. I'd like to make a judgement on whether these mods affect the sound in 
any way compared to a standard production TB-303, even when nothing is 
connected to the jack sockets.

Before anyone says "open it up and trace out what wires go where", I had 
thought of that!  I'm not being lazy, I'm just trying to minimise the number 
of times I open up the unit as the old plastic enclosure and PCBs are quite 
fragile.  There's also the risk of human error if I trace out the 
connections vs working from a schematic if one exists somewhere?

Has anyone ever fitted one of these kits?  It looks like Kenton Electronics 
still do them...

https://kentonuk.com/product/roland-tb-303/

...but the PDF docs at the bottom of that page don't tell you how to install 
the kit.

-Richie, 



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