Add 1M resistor between Q1 gate and GND. This is missing component on schematics. This is on pedalpcb schematics https://www.pedalpcb.com/docs/SOFTii.pdf With this pedal works consistently, there is no need to "reset" it after each 10 seconds, tone is not dark anymore and different transi...

It's the 2008 revision, but the specific model I traced was from 2014. As far as I understand, the next revision after 2008 was the 2020 one that released this summer, with toggles on the outside.

We were sorely missing any info on the post-2003 models, including the XLF and Bluesberry variants, so I traced a post-2008 Hotcake which includes internal switches for XLF and Bluesberry modes. Crowther goops these pedals pretty effectively, so it was a pain, but hopefully worth it! crowther_hot_ca...

I was finally able to get one of these and trace it, so we're now 3 for 3 on Dinosaural designs (the Tube Bender and OTC-201 are the other two pedals he designed). Here's how it looks: opa101_trace_schematic.png Not an exact copy of the Tube Bender by any means, although it does share the same overd...

Don't use the gaussmarkov Eagle libraries... they're super outdated and not very well designed by today's standards. They were a game-changer when they first came out, the first pedal-friendly set of libraries for Eagle, but they don't hold up well in 2020. His tutorials aren't great either - for ex...

DjPsychic wrote: ↑03 Sep 2020, 19:54 Feel like doing a layout of the Yamaha?

Well, if you're gonna twist my arm...

Ben N wrote: ↑14 Sep 2020, 19:32 Nice. Looks like a worthwhile build. Might NE5532/NE5534 be a good substitution for TL072/TL071?

Yep, will be a little higher current draw but on paper it’s a better audio chip. Should work fine!

Not dissimilar to an AC/RC Booster! Tube Screamer frontend (op-amp feedback diodes) with a 2-band Baxandall tone control. This is only a couple years before the AC/RC appeared in 2002, so I wonder if Xotic got any inspiration? Popular Electronics was an American magazine. It's not a terribly origina...

The Cornish ST-2 was originally designed for David Gilmour, and released as a standalone pedal in 2007. David is notably associated with the Colorsound Overdriver and so it was suspected that the ST-2 was Pete's take on the Overdriver, although some ST-2 owners of course swore it had to be a complet...

The CC-1 is an original circuit by Pete Cornish, or at least as original as you can get with op-amps and diodes, but not a clone of anything else. He had said the OC-1 was an original design, and he was definitely correct to say so, so I decided to take a chance that the CC-1 was worth tracing too. ...

Most of the diodes are just for switching/power stuff, other than the 4 on the pot board for clipping. The 4016 IC is part of the switching as well. The TA75559S is a standard dual op-amp, just in SIL (single-in-line) format instead of DIP. It's common to see these in Boss and other 1980s Japanese p...

Is this circuit similar to anything else? Funny enough, I was just doing a layout for the ETI Magazine "Fuzztone" project (Dan Coggins/Lovetone design from 1993) a few days ago and the similarities are pretty interesting - single-stage soft clipping with stacked diodes, followed by a Big ...

I've been really hoping to get one of the original Tube Benders so I could trace it and see if it was different from the magazine version. There are only 150 of them out there so it seemed pretty unlikely, but it was on the wish list anyway. Well, this summer I found one, and after tracing it I can ...

SMD capacitors have to be completely desoldered to measure, unfortunately... there’s no other way since they’re not labeled. Measuring them in-circuit won’t tell you the real value with any degree of certainty.

So uh - this is interesting. I grabbed one of these just to get a concurring trace since there were some unresolved questions about the original schematic and I thought we should solve it once and for all. But mine is different - it has 8 transistors (all 2N5457). The PCB layout is completely differ...

The carbon comp resistors must be NOS or something because the resistances I'm measuring are way off. This isn't my area of expertise, but I was shocked to find 10k resistors with 5% tolerance (gold band) measuring at 15k. Almost every carbon comp resistor I measured was around 20% off. There are a...

See attached. You can see that the diode polarity is always cathode down, anode up, for all five of the diodes. The underside photo is small, but you can make out the corresponding jumpers in the upper left. So I still think the schematic I drew is correct, but I do welcome a second set of eyes!

I couldn't find any record of anyone cracking open a Bass RC Booster, so I did one along with the AC and RC traces. (They all share the same PCB, so the second and third ones go pretty quick once the first one is down!) xotic-bass-rc-booster-trace-schematic.png Not much changed from the standard RC ...

I traced a recent RC Booster since there are a few different schematics out there and I wanted a definitive trace. xotic-rc-booster-trace-schematic.png The only real change from earlier schematics is that the input capacitor C7 is 1uF instead of 47n. No real difference in tone since the cutoff frequ...

There are a lot of discrepancies in the AC Booster schematics floating around, some perhaps due to tracing errors but most of them just due to Xotic changing things along the way since they are known to tinker incessantly with their circuits. My thirst for accuracy got the best of me, so I traced a ...