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I built this stock and found it to be a little noisy with my rig. This isn't a criticism per se—my amp is particularly sensitive to noise and PT2399s aren't known for their fidelity.



I received the enclosure as a Christmas gift and wanted to show off as much of it as possible. Label maker labels are encased in clear coat.



The output volume was mounted internally. The "tails" switch grounds lug 2 of the "Repeats" (or Regen) control by connecting it to lug 6 of the bypass footswitch. This grounds the output of the PT2399 when the "tails" switch is activated and the effect is bypassed.



Above is the original schematic with my values in red. R2 and R4 were changed because that's the closest value I had on hand. R3 and R13 were changed to increase the dry and delay output. Unity volume can then be achieved with a lower "Output" setting, which attenuates the noise from the PT2399 and the rate LEDs. C14 and C15 were upped to reduce the hiss in the repeats. They still have that bright bell-like quality that's the signature of this circuit, but there's no burst of white noise that you get at higher delay settings with the stock values.

On the whole, I'd recommend this circuit. I don't think most people would hear the increase in noise floor with most setups.

Looks good inside and out! How'd you manage to get the graphic over the hammer-tone paint? Was it a stamp?

I haven't done a ton of transistor tasting, but because the second transistor sends negative feedback to the first transistor in a Fuzz Face, the ratio of gain between the two transistors is more important than the absolute gain. If Q2 is roughly 1.5 the beta of Q1, you should get similar results regardless of what the beta actually is.

I had a similar issue with my build and ended up reducing R11 from 2k4 to 1k2. It definitely still squishes.

I'm seeing the reverse. It also seems to be my account.

This video came out today. I different exploration of parallel dirt.

Between the 555 and the PT2399 you have two digital clocks. The risk of heterodyning is high. That's not to say that it could be done, necessarily, but you'd have to be very careful about your layout.

Thanks. I knew the Ross had an OTA in it, but I thought it was being used as a voltage-controlled resistor—I should have looked close at the schematic. The Aphelion actually appears to be doing what I want to do; saturate the OTA. I'll definitely be looking into that.

I'm trying to understand the LM17300, but haven't been able to find much information beyond the data sheet. Explainer articles or videos all insist on using a split power rail and don't do much in the way of practical examples. Does anyone have a source that shows how to use an OTA as an amplifier (as opposed to a resistor, or in a filter)? I'm especially interested in examples of using an OTA without a split power rail.

Thanks, all. I know someone here must have some experience.

The insides look great! Do you have any plans for the outside yet?

I wired up different pairings using my go-to drive circuits: Peach Fuzz, Cream Puff, Timmy vII, Crunch Box & fOXX Tone Machine.

Peach Fuzz + Timmy is a monster.
I've been struggling for years to transition from fuzzy rhythm tone to fuzzy lead tone.  When it comes time for a lead, I'm often so saturated with gain that I can't clearly poke through the band mix, even with my AC30 fully cranked.  A solution I'm forced into is to reducing gain.. which also reduces 'cool..' so having the ability to leave the rhythm fuzz ON, while adding a nice, clear overdrive alongside of it allows for a much more prominent sound that doesn't lose 'coolness.'
Also, starting with overdrive, then adding fuzz underneath is great in some songs.
I haven't tested it full-band yet, but I've got really high hopes based on what I'm hearing.

Peach Fuzz + Crunch Box
Cream Puff + Timmy II
Cream Puff + Crunch Box
These combinations can do the same tricks in different flavors.

Issues with the Tone machine make me suspect it's out-of-phase, so I built up a little phase switch from that schematic you posted (THANK YOU!) -I'm about to test that out.

That's awesome! The rhythm/lead thing is definitely something I butted up against too. I think it would be cool to try delays and modulation in parallel as well...I might have to work up a parallel looper.

Holy smokes.. I got this switch assembled and I'm trying some parallel combinations today.

I expect mk. II to have four loops, with stereo panning, and adjustable millisecond delays for that authentic quad-tracking sound! 

But, seriously, I'd love to know what cool combinations you find. Also, what potentiometer arrangement did you end up with?

I've updated the schematic in the original post after finding a minor value error. The layout was correct. Thanks, Dawson, for pointing them out!

Do you have recommendations for class D power amps?

That's the cap! Smaller cap will yield less bass in the situation. I would recommend socketing it and experimenting with values.