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.