La Guillotine -- allons enfants! [Kingslayer]

[midwayfair]

With artwork depicting one of the most famous King (and queen and duke ... and inventor ...) slayers of all time. The enclosure is blue starlight from Pedal Parts Plus. There's a basket drawn on the "out" side of the pedal, too. I think we all know that's that's there for. don'tslipintheblood.

I decided to have a little bit of fun with the hard clippers, which are all germanium: top to bottom, they are OA126 (.542) & D9J (.271) [asym], and 1N34A (.37) & OA1160 (.37) [sym]. All of these were the most severe Fv outlyers in their series that I had on hand, except the D9J, which I picked because it had exactly half the Fv of the OA126. Finally found a use for having hundreds of diodes in the house! (twitch, twitch.) One thing that's really nice about this setup is that the average Fv is very close on both sides, preventing severe volume jumps between settings. Soft clippers are 2N7000s, with a Smallbear BAT41 (yes, there's a difference in average Fv compared to other BAT41s I have) on one side for more variety. I like asymmetric clipping, and having two different choices for various flavors of it is very nice. On very low gain settings with both sets of diodes in, it gives a far more amp-like breakup compared to other klones I've built.

I reverted to the 3.9 tone cap, which unfortunately was one of my only non-Panasonic caps in the build. I already feel like I'm playing under water on the CCW side of the tone knob, so I saw no reason to cut the treble at all (I also like treble a lot).

Overall it's a very nice sounding project and I'd run it on my board in a heartbeat over a stock centaur.

I did have one issue: With both sets of diodes lifted, gain settings near the maximum position cause motorboating. The motorboating stops when either set of diodes is switched on or the pedal is switched on and off again. Granted I'm never going to use those settings (because it hits transistor sound waaaaay before then), but it was certainly a surprise that there's also a tremolo hiding in the pedal!

Thanks, Brian!

[madbean]

Cool, glad you got to experimenting on the diode selection.

I'm surprised about the oscillation--I worked with it a lot to prevent that even with all the diodes lifted (or at least I did not have that issue on my build). You could reduce the 1M resistor in the feedback loop to either 820k or 750k. Honestly, I don't really expect too many people to run it at max gain without any diodes...it sounds pretty cool up to the half-way mark that way (like the klon if you use that option) but after that you get some nasty op-amp distortion which sounds quite harsh.

[midwayfair]

Cool, glad you got to experimenting on the diode selection.

I'm surprised about the oscillation--I worked with it a lot to prevent that even with all the diodes lifted (or at least I did not have that issue on my build). You could reduce the 1M resistor in the feedback loop to either 820k or 750k. Honestly, I don't really expect too many people to run it at max gain without any diodes...it sounds pretty cool up to the half-way mark that way (like the klon if you use that option) but after that you get some nasty op-amp distortion which sounds quite harsh.

Yeah, that's why I wasn't too worried about it; if I'm lifting the diodes it's because I want it as clean as possible (and it sounds excellent that way, I must say, more open than just zeroing out the gain with the diodes in) and I'm really just a "touch of gain" guy regardless. Anyway, I didn't catch the issue before I boxed it, and it's really, really securely in there now, so I'll most likely leave well enough alone.

[jkokura]

I too admire the approach to clipping Jon. I'll have to talk with you sometime about all the experimenting you've been doing!

Jacob

[mgwhit]

Cool build!  I love the guillotine, and I always enjoy hearing about your diode experiments.

[jubal81]

I did have one issue: With both sets of diodes lifted, gain settings near the maximum position cause motorboating. The motorboating stops when either set of diodes is switched on or the pedal is switched on and off again.

I got into the same territory. I ended up putting in a new TC1044 and couldn't get a click no matter how hard I pushed it. I've found them to be kind of sensitive, but I'm pretty rough on them. I've been thinking about employing a shunt zener when I use charge pumps. Then again, maybe I zapped it with static electricity or something. Whatever it was, a swap seems to have solved it.

Forgot to say your build looks fantastic as usual. Creative, clean and pro looking. I love where you went with the theme. I might have to steal your idea and think of some assassin-theme for mine

[midwayfair]

I might have to steal your idea and think of some assassin-theme for mine

Assassin!


Thanks for the kind words everyone. I'm looking forward to seeing where other people go with their builds.

[pickdropper]

I really like your painting on this one, Jon.  Looks really good.

[nzCdog]

Great pedal!  Nice artwork 

[lincolnic]

Digging the art, as usual.

[raulduke]

Love the build and love the artwork.

Viva La Revolution!

[gtr2]

Nice job Jon 

Josh

[midwayfair]

Thanks guys! Don't lose your heads! hehe

[Vallhagen]

Very nice build:)

I look fw to put together a kingslayer as well. PCB should arrive any day:)

Cheers!

[Bret608]

For me it's the Fleur de Lis that really push the art over the top! That could be my Louisiana roots talking.

Love how you mixed the diodes but used a very deliberate approach to matching/purposely mismatching the forward voltages. Inspiring!