MFOS

Sound Lab Ultimate Notes and Photos

I’ve finally completed the MFOS Sound Lab Ultimate and despite the scattered moments of irritation over the past 8 months all-in-all I think it’s come out great. I’ll assume folks reading this are familiar with DIY projects so I skip the detailed build notes and move directly to some key points that I think will help anyone who is considering building this project.

1. Read all the instructions before you start. This is a classic ‘rule-of-thumb’ and no matter how many times I ignore it, I am always reminded through costly errors that I should have followed it. For example, after spending many hours putting together my own parts list in Mouser for this project and bitching to myself that Ray Wilson should have a parts list link on his site I finally discovered that he in-fact does. Putting together a project parts list is easy when you only need 20 parts, but given the size of this project you don’t want to go through the painstaking process of doing it yourself.

2. If money permits, buy all 1% tolerance resistors. The design calls for some which are 1%, and some which do not need to be 1% but some of these are the same valued resistors. You don’t want to realize that you just soldered twenty 10k 5% resistors down which should have been the 10k 1% resistors. It’s an easy mistake to make. And I made it. Speaking of mistakes, double check your work before plugging in. notice anything peculiar in the photo below? I’m glad i spotted that error before plugging in the power supply.

3. Also, if money permits, spend some coin on good knobs. It makes a huge difference in the look and feel of the finished project. If you do use the knobs suggested in the project plans purchase extra. Many of mine arrived missing the mounting screw rendering them useless.

4. Also double check the shaft type of the knobs in the parts list. After receiving my order and setting up the control panel I realized half of them were D shaft and half were full round shaft. Mounting regular knobs on d-shaft pots makes the knobs rotate in an elliptical fashion and, although not critical, it’s a detail that just frustrates the hell out of me.

5. I struggled with what to do about an enclosure but I found this gem at hobby-lobby. It’s a painter’s box or rather “a wooden artist’s case”. Either way, it was 19.99 and I had a 40% off coupon so it was a score. The MFOS SLU fits perfectly into it with only slight modifications. The one pictured on the website looks way nicer than the one I picked up but I’m not sad. Hobby Lobby saved the day again with cheap pre-fabricated boxes for any project.

6. On the wiring side it’s a toss-up. On the one hand, solid core saves you a ton of time when tinning the ends of your wire and it’s easy to bend into shape. But when you have to run approximately 120 hook-up wires stranded may be the way to go for flexibilities sake. Your call. I’m happy w/ the solid core.

7. If you’re willing to risk it, I think it might be possible to forego the process of hand matching your transistors. I originally hand matched a couple dozen xxxx transistors and they needed it. However, I matched another handful of xxxxx and they were all within .002mV as per the specs. Perhaps it was a fluke, but building the circuit, and then actually testing the transistors took all night one evening.

RF’s DIY Modular Synth Pages

This is from another ElectroMusic.com user named ‘RF’. ‘RF’ [Nick] has built a monster DIY analog synth built mostly from MFOS kits from Ray Wilson. RF’s site gives a great deal of information on where he got started when looking to explore DIY synthesis. One of these days I’m going to take off 5 years and photograph all of these synths and publish it in a luxurious hard cover volume with nothing but gear-porn quality photos.

RF’s DIY Modular Synth Pages.

Music From Outer Space – WSG mods completed

MFOS WSG
Usually I will just post a couple images with brief descriptions of the process behind a project I post. But with the completion of my mods to the MFOS Weird Sound Generator I wanted to offer up a couple of the dos and don’ts I learned while working on this.

Dos

  • Do buy an Alesis Quadraverb on eBay for 10 bucks and use the 1 space rack case instead of buying something new.
  • Do save the seemingly useless Alesis front panel because you never know… you might need it (and I did).
  • Do take the time to measure twice, three and four times.
  • Do be prepared to find out that your measurements might still be wrong.
  • Do go with your instincts and spend the extra cash to make it look nice.
  • Do use pre-tinned solid wire (and save a lot of time).
  • Do drill or punch starter holes.
  • Do look up parts you’re unfamiliar with in Mouser’s four inch thick hard-copy catalog. It’s far easier to get an idea of what your actually buying sight unseen.

Don’ts

  • Don’t waste three weeks comparison shopping at on-line front-panel design shops. You spend a lot of time learning stripped down versions of proprietary CAD tools that can be enormously frustrating and in the end the price difference isn’t that significant.
  • Don’t do anything less than 2mm on the width of the front panel.
  • Don’t ever go back to stranded wire.
  • Don’t pass by the $20 Quadraverb and waste two and a half weeks looking for a better deal. 18 days is worth the extra $10 bucks compared to the money you save from buying new.
  • Don’t rush.

And lastly, Don’t do this:
MFOS WSG

When you can do this:
MFOS WSG

This is a nice shot of the whole unit which shows the excellent work the folks at Front Panel Express did on this. If you’re considering spending the coin on a custom front panel and on the fence about it I can say without reservation that my expectations were exceeded and I will never doubt that it was money well spent. Just make sure you have your measurements right. I made a couple mistakes which I was able to work around without major issue but it was at the expense of several days time figuring out alternative solutions.
MFOS WSG

You can see more images of the final build on Flickr here…

MFOS – Weird Sound Generator

Sometimes you don’t want to have to spend hours researching designs and finding parts to build a project… sometimes you just want to buy everything you need at once, solder it up, and have fun without the worry of troubleshooting your design. At those times a kit is perfect and in this case that’s just what I did.

I’ve posted about MFOS before. They manufacture a number of kits from entry level to advanced synthesis kits. I decided to go with the ‘WSG’… or Weird Sound Generator. Ray Wilson has some excellent designs that are really fun to put together. I managed to get this up and running in a weekend without any hassles and it sounds great. It’s basically two squarewave generators with LFOs and a resonance filter. If your just starting out this is perfect… and even though I’ve been doing this for a while it was still a ton of fun. Ray’s taken all the hard work out of the process and made DIY synthesis simple, straight forward, and well documented.

He provides all the documentation you could need including wiring diagrams, pcb templates, schematics, block diagrams, and parts lists so I won’t duplicate that here. I’ll just add some comments on the build and a video of the finished project at the end of the post…

Here we have the parts list laid out…

Most of the components have been soldered to the PCB at this point. All the parts are included in the kit and none were missing.

The finished PCB sans ICs.

I used a aluminum enclosure from an old broken gemeni turntable mixer I bought off of ebay. I’ve had great luck finding things like this for 10 bucks or less sometimes and they’re perfect when you need spare knobs, op amps, or enclosures. I just flipped it upside down and took of the rubber feet. Holes were drilled using a step bit (these are a must have for drilling good holes in aluminum enclosures).

Here is everything wired up.

This is the PCB finally wired up. One complaint about this is that the holes on the PCB for all the wiring are placed all over the PCB which makes for really messy wiring. I found that extra care was required to make sure the wiring didn’t bend too much and come detached from the PCB. It seems like using headers would be a much easier way to go about this the next time around.

When I put this together I first soldered the hookup-wire to the board, then to the components on the panel which makes it really difficult to keep things neat and tidy. Next time I will wire up the panel first, then complete the board, then make my connections to allow for a cleaner layout.

Just a tip for beginners… don’t shrink the heat shrink tubing until you’ve tested your work and are certain it works. It’s a major irritation to have to remove heat shrink tubing after you’ve already… well, shrunk it.

MFOS Web Tools

Music From Outer Space (MFOS) is an extensive resource for anyone involved in DIY audio.  Anyone regardless of experience level should have the site permanently bookmarked as it has something for everyone.  Although focused on DIY synthesis almost everything on the site can be used in your projects.  One their most recent additions is their web tools, specifically their “web schematic“.  From their site:

MFOS Web Schematic is a schematic capture tool written entirely in JavaScript that lets you work on a schematic anywhere you have a browser (FireFox, IE, Chrome, and Safari). You can save your work because the schematics you make can be serialized to XML and then emailed to a friend or a collaborator. You or your friend just paste the XML into the Load dialog and voila… you are looking at your schematic. I see Web Schematic as a communication and teaching tool. Students can communicate with one another via emailed schematics and teachers can use the tool in the classroom as well. You can also download a PDF of your schematic for printing.

Ray Wilson at MFOS also provides a virtual breadboard designer, panel designer, and a few essential calculators including a Resistor Color Code Calculator, Parallel Resistance Calculator, Non-Inverting Op Amp Gain Calculator, Inverting Op Amp Gain & Offset Calculator, Comparator Calculator, and last an Inches to Millimeters Conversion calculator.