Matching JFETs for Modulation Effects
So we've been doing a lot of work to put information into the wiki here on the site. We've completed the catalog of all the pedals we have. This doesn't include just the brand-name already-assembled pedals by larger manufacturers. We actually also undertook a lot of work scanning different websites and companies that offer more than just the run-of-the-mill pedals and found ourselves drawn into kit pedals and pcb-only pedals. Now, of course this site is about tube amps, and tube amps alone, while they take us to the promised land of heavy music, they won't alone keep it interesting.
So we have ninety-seven (97) Kit- or PCB-based pedals. We've purchased all the necessary electronic components needed for the PCB-based pedals. Just like our efforts to get cool, interesting, well-known, musical and reliable amplifiers, we've attempted the same thing with the Kit- and PCB-based pedals. Most of what we're putting together consists of old pedals that were novel that are no longer available, and pedals that are wholly new, conceived by people for new sounds and new applications.
You can find the pedals in our collection here in our Wiki. Not everything is complete, but as days go on and as projects get completed, so will the entries. We've spent a lot of time in the process of conceptualizing what we wanted for the wiki and how we were going to present it. You'll be able to see what we're doing and where we're going with this piece of the Thermionic Studios project pretty quickly and easily and once you see it, it should make a lot of sense conceptually.
Really what this was about was something new that we found on the Rullywow Pedals and Projects website. We're not currently, but will likely soon start getting some more Kit and/or PCB-based pedals - mostly phasers or some kind of other modulation. What we've gotten to this point doesn't include chorus (mostly because we don't care for chorus) and phasers (love em!) or flangers (love em!). In fact we didn't even know that we'd have to match transistors for phasers. This is where the Rullywow website comes in. We bought our PCBs from Rullywow a year to 6 months ago. In the time since, we've sourced electronic parts to assemble the pedals. That said, in the time we've been sourcing parts, the Rullywow site changed!
There is still the usual PCBs available for purchase, however Rullywow has also put up "Free Projects". One of these "free projects" (that I had to spend money for anyway!) is a very small JFET test board that allows you to test and match JFET transistors for building functional phasers. We're going to be building some phasers in the not-so-distant future so this is more necessary than we first thought when we stumbled upon it.
What follows this link is a pretty comprehensive guide to developing a tool to help matching JFET transistors for use and performance in phaser pedals. It's written by R.G. Keen who is very well known for contributing to the DIY pedal movement - so we owe him a lot.
The board as linked from Rullywow goes to a fabricator. I had to buy a minimum set (3) of boards from a third party fabricator to whom Rullywow has provided a link. For us the cost of 3 small boards was negligible at around $7.00.