06 January 2010

Wilba MB-6582 (Part 1)

I bought a bunch of old 6581 sound chips a long time ago coming from the famous Commodore 64 home computer. And I was planning to build a synthesizer with them some day. And then I found the Wilba MB-6582 project on the Internet which is basically a Midibox design with 4 Pics and 8 SID chips on one big PCB. On the website is also a very nice design for a case and you can download the front panel files from there. I ordered the PCB's along with a components kit for the base PCB a long time ago and last week they finally arrived. And I couldn't wait to start on this project. Here you see some of the resistors already in place on the PCB.

The documentation for this project is neatly done online in a Wiki that is updated when necessary. It gives great information on the different build possibilities. It was originally designed for the 6582 SID chips as the name suggests. These run on 9 Volt, but it can also handle the other types of SID chips. I use the original 6581 and they need 12 Volts. The builder actually offers 4 options to build the PSU section. I chose option B because of the need for 12 Volts and I want to use an original Commodore 64 power supply to power the synthesizer later on. In the picture on the right you can see a picture where I just mounted all the IC sockets on the PCB. There are quite a lot as you can see.

Here is a picture where also the backpanel components are installed. On the left is the power switch that is actually the same switch as used in the original Commodore 64 and next to it the power connector. Then two midi connectors and next to that 4 stereo audio output jacks. Yes this baby has 4 stereo output channels :) You can also see that I installed the electronic parts behind that. This is all for the SID chips itself. It is quite dense in these parts and you actually have to install some resistors standing up because otherwise they wouldn't fit. You can also see the capacitors next to the SID IC sockets are on little parts of IC headers. This way you can swap them since for the 6581 you need different values than for the other SID types. And I don't know yet if mine actually work.

And here is a picture of the finished base PCB. Here also the PSU section is in place. I didn't put the IC's in yet. I need to run some power tests to see if I didn't make any mistakes in the PSU section. I don't want to blow up my precious SID chips :) But since they are all on IC sockets it is just a matter of putting them in. Next step is another PCB that is used for fitting the front panel components like all the leds, switches and rotary encoders. I just ordered these components from Mouser and I'm waiting for them. I also got a display from CrystalFontz in the US. If you are curious what this project is going to look like or want information to build one yourself do visit the MB-6582 Wiki at this URL: http://www.midibox.org/dokuwiki/wilba_mb_6582


Joeri said...

Hi Michel,
I am just ordering my parts for the MB-6582. Where did you order the S1 Switch (the C64 one) in the Netherlands?
Or did you harvest it from an old C64?

Synth.nl said...

No I got a parts kit for the Base PCB from Smash TV. It was in there. Good luck with your MB-6582 project. I hope to finish mine soon :)