The Return of the King (of Tone)

One of my earliest builds was a clone of the boutique Analogman King of Tone pedal. The King of Tone itself is a very sought after double overdrive pedal, with a variety of clipping options (most of which are set using internal DIP switches). The "real thing" is currently in Version 4, and on Reverb they still tend to start at around $600 for a real one and go up from there. The waiting list for an original remains long as well. My first build was in my "pre-dino" days - and I'd bought a kit from Germany that included an unpainted enclosure, the PCB, and all of the parts. I substituted some good matches for the original diodes rather than using the stock ones with the kit, though, as depending on who you ask the King of Tone has "magic diodes" much in the same way the Klon Centaur / KTR does. I'd always wanted to circle back and make a real "dino" version of the pedal, so I finally took the plunge.

For this particular build I used the AionFX Theseus (Rev 1) board. AionFX didn't have a board for the King of Tone when I built my original pedal back in 2021. The Theseus board has since been further revised (Rev 2) moving from a single six-position DIP switch (in the center of the PCB above) to two separate three-position dip switches (one for each side). There were a few other minor tweaks made to the board as well. The values of the power filter resistors were changed from 100Ω to 47Ω in order to slightly increase the circuit's voltage. The LED current limiting resistors were also increased proportionally because of the shift in voltage. I decided that even though I was using the earlier revision of the board, I'd incorporate the voltage change in my build. 

For the most part the build was straightforward. I used my normal combination of metal film resistors and metal film capacitors. The metal film capacitors are all 5% tolerance except for the 1μF ones, which are 10%. Like my previous build, I went ahead and sourced authentic diodes (or as authentic as you can get at this point) for this particular build. AionFX indicates that they do indeed clip at a slightly different voltage, though many builders claim to hear no difference in sound even using more conventional silicon diodes.

As with most AionFX builds, a fair portion of the circuit is on the 3PDT daughter board. The Theseus is no exception. However, this is where one of the slight modifications I had to make in order to complete the build in my chosen enclosure. The build itself is designed to go in the slightly unusual Hammond 1590BBS enclosure. Unfortunately my main source of UV printed enclosures doesn't stock the 1590BBS, so I had to try and go with the 1590BB2 which, per AionFX, "about 4mm shorter" than the BBS. I therefore had to put the electrolytic capacitors on the bottom side of the daughter board rather than the top in order to get everything to actually fit. 

Because I wanted to include the send/return loop in the build, I had to make some more adjustments to accommodate the shorter enclosure as well. The connection points for the switched stereo jacks used in the loop would have extended past the bottom of the enclosure. I therefore had to carefully bend over the connection points so that they would not contact the enclosure bottom. I used jumper wire for several of the ground connections - unfortunately that made insulating the loop jacks with heat shrink tubing nearly impossible. I managed to get it on a couple of the connections, but that was it. The rest of the connections - input, output, and DC jack - all have the normal tube insulation on them. Wiring the loop was especially tedious, but it does work flawlessly.

For the enclosure itself, the King of Tone must have the King of Dinosaurs - so enter the "T-Rex of Tone" (not my most original name, I know... I may change it if I build any more of these). I really love how the enclosure itself cam out, though. Rexie the T-Rex is yet another amazing piece of art by my wife ADK. 

The pedal sounds as expected in all of the various modes, but this sort of brings me to my one issue with this particular build. While the AionFX Theseus is a faithful recreation of the original King of Tone pedal, it shares all of the same inconveniences with that particular design. Specifically, the fact that four of your controls are internal only - Presence, Soft Clip, Hard Clip, and High Gain. This is one area where the PCB Guitar Mania PCB that came with my earlier kit is actually superior (in my opinion) as all of those controls are external on that particular board. It is sort of the same philosophy that The Tone Geek used on his Above Top Secret TSV808 board - all of the internal controls are moved to the top of the enclosure there as well.