SEQUENTIAL CIRCUITS PRO~1 MONOPHONIC SYNTHESIZER WITH HIGH SPEC MIDI

OakleySound tb3030 + midibox64 project

I finally got around to building the TB3030 from Oakley Sound. I decided

it would be cool to combine the basic TB3030 board with the Tbdac, midi->Cv

converter and then a hardware midisequencer all together in a single desktop unit.

I also wanted something that was compact and portable. The question was ..what hardware midi sequencer to build? Well I didn’t want to re-invent the wheel and start from scratch ..so a quick trawl of the web with google power turned up a fantastic hardware midi controller/sequencer design by Thorsten Klose in Germany.

To see and read about all the very cool features of the midibox64..check out Thorstens pages:-

http://www.ucapps.de/midibox64.html

The midibox 64 is based around a PIC16F877 microcontroller..one of the newer PIC devices from Arizona Microchip. A hex file of the midibox64 firmware is availble from the midibox64 website to download and program into a blank 16F877. The midicontroller/sequencer features are accessed through a menu driven 2x16 backlit LCD screen.

Here are some latest pics of the project:-

The above shows some pics of the case I bought from Hammond Enclosures:

http://www.hammondmfg.com/dwg16.htm

(model number 1456PH3WHCWW..other sizes available)

It’s a nice sloping desktop model with real walnut endcheeks(!) and aluminium top panel.

Getting the TB3030+TBDAC+Midibox64 boards plus 3x16 = 48 Pots into this case was a bit of a squeeze..but with some careful routing of wire looms etc it wasn’t so bad. I would have liked to

have been able to squeeze another row of pots in (the Mididbox64 supports up to 96 pots !!)

but it would need a larger case.

In the above, the pots without knobs are those of the TB3030..still waiting for a batch of silver knobs I ordered which are like those on the sequencer but slightly larger. The M64 supports push buttons and leds. In sequencer mode the lower 16 buttons send note on/off midi data. Depepnding on what sequencer mode you choose..the top row of sequencer pots can control note value (pitch) the second row velocity and the third row gatetime. I have only just started exploring other possibilities..the power of the M64 is probably overkill for the TB!

One excellent feature that Thorsten has added is the ability to save different setups of the sequencer knobs/buttons to different memory banks (using a 24LC256 serial eeprom).Each 24LC256 chip can hold 16 banks. What is cool is that you can switch between banks in real time as the sequencer plays..I just started exploring this feature..but it looks like it possible using this to sequence different note patterns just like the original TB303!

‘TBDAC’ special Bracket made from L-shaped Alum.

Midi->CV converter extrusion. Allows pot-board to have

From Oakley Sounds. same angle as the sloping case top.

Accepts MIDI data

from the MIDIBOX64.

PCB standoffs allow precise adjustment

of pot-board hieght to fit top case

TB3030 Board from Oakley Sounds

Midibox64 PCB. I etched I added a 1000uF/16V

this on double-sided copper Capacitor acrross ground/+5V

board. The top side has copper to add further stabilization.

un-etched which acts as

a convenient heatsink/ground plane

24LC256 serial EEPROM

memory for the ‘bankstick’

I plan to add several more

and maybe switch between them

using a frontpanel switch.

LATEST PICS OF tHE PROJECT (02/6/02)

I finished the longst part of the project (as with most synth projects!)..cutting out all those holes

in the top panel of the case and adding the artwork/legend. I used various hole punches made by ‘Q-Max’

..they cut perfectly round holes every time. To make the square holes for the sequencer buttons..I used a round

(12.5mm) Q-max punch and then various needle files to square off the hole. It takes time ..lots of time ..to

get a decent finish.

I decided that I would spray paint the top panel and then add the artwork/legend by a method I have used in the past..namely using so called ‘lazertran’ waterslide-decal paper. ( www.lazertran.com ) . You can find detailed instructions of how to use this great product on their website. Basially I created the coloured front panel design using a new front panel designer software from ABACOM in Germany called FRONTDESIGNER

www.abacom-online.de. Unlike the free software frontpaneldesigner from Shaeffer (also very good), it is a true windows product that allows you to use any of the available windows fonts in your design. I decided that the so called ‘TR909 fonts’ that were circulated on the synth-diy mail-list would look very cool on the front panel ..so I used these throughout. Anyway FRONTDESIGNER is an excellent product..I would recommend it .

The front panel graphic/legend was made using lazertran water slide decal paper. For details on this method

see my pages on front panel creation :- frontpanel creation

Here are some pics.. thepanel is now complete! Just need to wire up the memory banks selector and

the 6 midi event buttons!

Front panel artwork designed with FRONTDESIGNER:-