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I don't have a lot of great advice on this, but my cro-magnon approach is to look at the schematic and start at the output - I use a screwdriver and I tap the whole circuit starting at the output jack. The result is a loud clicking sound if the circuit is working and nothing if it isn't... I mean, at the very least because I'm cross referencing everything to the schematic I might come across a turned around diode or a misplaced resistor.

FWIW, I don't "rock it before you box it" - I probably should but so far I've gotten away with it.

I don't know if this is true for you, but my biggest problem, 10 times out of 10, is a cold/incomplete solder joint. Since I started using solid copper wire the problem his dissipated somewhat but for more complicated things (e.g. perfboard builds with multiple circuits and switchable buffers etc) It's still a problem.

The 8ball is a straightforward circuit so it should be simple enough to troubleshoot... You don't have any sound at all so I would check the clearance of the potentiometers above the board. This has been an issue for me especially with the pcb mounted builds. I would also check to make sure the diodes are wired in the correct orientation - the 1n4148 diodes are super easy to identify but the LEDS can be tricky. Does it make sound when you toggle between the two positions?

I kind of want one of these now... Must... Remain.... Strong....

For real though that's the coolest looking pedal I've seen in a while.

Guitar: telecaster
Amp: hiwatt dr103 (never played one though... Just love the sounds Pete Townsend and David Gilmour got through them)
Pickup: Seymour Duncan Jerry Donahue
Car: Honda s2000
Food: smoked ribs (6+ hours at least)
Pedal: fatpants
Book: brave New world (I know it's cliche but between this and breakfast of champions I just couldn't choose)

Here's the todo list:
+Run the JFETs at a higher voltage. I'm looking at 24V.
+Better (and more) low-pass filtering.
+New tone stack (James sounds good in theory, but I find it kind of boring and I want this to have some character)
+Use a single JFET for the OD instead of the MuAmp
+Tweak the gain in each stage of the Muffish

It almost sounds like a jfet based OD hooked up to a muff? Or I wonder if you could have a gain stage using the fatpants switching system so essentially the front end is a jfet boost and then you add in (for example) on one setting 2x1n4148 to ground, then beyond that add another jfet with some 1n4148s in a negative feedback loop (which is a pretty gainy 1 transistor design actually:



Man not to derail but this thread has me thinking lol.

At any rate I love the design and enclosure.

Edit: sorry for the double post

I didn't see this thread when it was originally put up but holy crap...

Whether you build good sir I  want one of.... Incredible stuff here

Okay, so I do have an update - because I can't help but mess with pedals I swapped q2 out for a j201 (and t2 for a 50k and r5 for a 1.8k)

However I've found that the j201 with the 1.8k isn't a particularly great sound. Kind of paper-y no matter what the bias. I swapped it for a 1.5k which is better but I'm thinking about trying a 1.2k or a 1k (which would make it the same bias essentially as runoffgroove's defunct Thor circuit)

The reason I want to stay with the 1.5k is that ROGs fender style circuits use that value whereas the Thor (and probably some others I'm not aware of) use(s) the 1k.

With the j201 obviously there's significantly more gain but the character is different as well. In combination with the mpf102 in q1 the j201 doesn't distort as harshly as the 2n5457 did. Whereas the 2n5457 didn't actually distort that much but did distort really aggressively, the j201 has more gain on tap than I'll ever use but clips more like a fender or mesa amp would (to my ears at least).

I think I'll keep it in this configuration for a while (once I settle on a source resistor), partly because it behaves more like an OD and less like a fuzz, and partly because I pulled a few traces and had to drill/rebuild the circuit around q2/t2/r5/r7 where all the damage occurred lol. My snow day is now a hybrid ptp/pcb design lol.

edit: Got a chance to play through this full volume - the bass knob has a noticeable effect at low volumes, so you can dial it in to where you want, which is nice. It's not a huge difference though. At full volume, it is absolutely crucial - you can take the pedal from "exploding amp mess" to "guitar gods through my fingers" sounds. Because this has been the case with all the pedals I've tried, I'm going to say it again - if your pedal sounds like thin crap at low volumes, try using it with the amp dimed... All I'm saying is I have a klone which sounds like garbage at full volume and like god at anything less, and a heavily modified SD-1 that sounds thin and wasp-y at low volumes but like an extra gain stage on a plexi when my amp is already cooking.

So, yeah. This pedal is great at low volumes - but it really shines when you're already getting distortion from the amp.

So, a caveat: Excuse the missed notes, the poor playing, the bad lighting, the quality of the camera phone microphone, etc. etc. etc. There's a reason this video is unlisted - it's here only to show what the flabulanche can sound like on some different settings.

I mention this in the video, but the guitar is a jazzmaster with seymour duncan p-rails pickups, and the amp is an 18w marshall clone.

Here goes nothing:

I plan on doing a purge here before too long - ideally, I want to have 2 pedals besides tuners. The first, a pre/wah - an always on OD/dist pedal (probably the flabulanche) with a wah in the same enclosure.

Second pedal will be a dual pt2399 delay with independent modulation - what I'm envisioning is a treadle to control the speed where you can go from almost a Univibe sound all the way to a faux chorus, that can modulate the dry signal or the repeats depending on whether the delay is activated

What pisses me off is when people refer to mayonnaise as ailoi... It's not garlic aioli you pig it's flavored mayonnaise. Don't pretend it's healthy because it has an Italian sounding name.

Aside from that sriracha is great but really easy to make yourself and adjust the ingredients. I really like sriracha made with green jalapenos and carrots for example.

Chimichurri is also amazing. As is a good mustard sauce. I don't know how many people here have had a chance to try a good mustard style bbq sauce but it's far and away my favorite for pork, rice, French fries, you name it.

I'm actually a little confused now - I have a mythical overdrive with oa126/1n34a diodes and there's a noticeable difference between them. Now if that's the forward voltage that's fine - I just don't understand all this talk about no difference between stock diodes and 1n4148 diodes which have a .65-ish fv.

That aside, I had no idea that op-amp distortion ever sounded good? I thought it was to be deliberately avoided?

No need to apologize, this sounds awesome! I think I'll build one similar to yours, and try the bass control in two different places to see where I prefer it.

I also like your idea for the boost control. However, you want to be careful about how you implement that. The method you've described would alter the bias on the BS170, which will result in a pop. The way you've described for adding a pot in parallel with R22 would actually drop the volume when the pot is in the circuit. (I had something similar wired into the fuzz face on my main board ... I spent a very long time trying to kill the pop and it was impossible, so I ended up building a separate boost.) If I think of something better using the existing topology, I'll let you know, but I'd start with nicking the boost switch method from the Lavache, putting it on the source of Q4 (probably go with a 10uF + 5K pot, in series with a 1M [at least], where the footswitch shorts the 1M), but that can also pop sometimes.

The way you wired the range control isn't really an issue; but you do still want to fix it because I imagine some settings ground the input and make no sound.

Anyway, I'm glad you liked the project in the end.

Yeah when the range control is all the way down I don't get any sound - which on the one hand isn't that big of an issue because I usually run the range switch between 10 and 5 o'clock but on the other hand it does bug me knowing it isn't wired correctly.

I had not thought about that altering the bias... Damn. The build doc says that r21 and r22 act like a volume control set to half so I figured having a variable pot in parallel would change the ratio of those guys to increase the volume. I'll check out the lavache build document and work on that - what I may end up doing is use the bacon bits board I have laying around (I used the in/out jacks I bought for that build so I could fit a battery in the enclosure which I had previously drilled for a different project)

At any rate I'll figure something out - thanks for the awesome project Jon. I'll film a little demo on Monday or Tuesday and post that in the demo section.

This thing is seriously good though. I couldn't be happier with how it turned out.

No graphics yet - this was more a proof of concept. I didn't know how well the "range" control would work, nor whether the mpf102 in q1 would have too little gain. Now that I'm thinking about it I'd probably call this one something like the 'chimera' or 'changeling' because it does so many things well - with the range dimed and the treble at zero it's almost woolly sounding, kind of like a slightly lo-fi overdrive pedal. Lower range settings take it from full range to tubescreamer, to treble booster near about 10-11 o'clock. Even with no gain and volume set to unity, and treble set to noon, and range set to full (range rolls off bass so fully up is the unaltered guitar signal) it does that wonderful "presence" thing I love so much about JFETS. At full gain I can go from hard rock/early metal at 10 on my volume knob to jazz at 7. AND there's no treble rolloff like with every other pedal I've ever played - you still get that amazing presence. It's like the klone I have except with a more neutral EQ and it cleans up better.

I'm actually going to keep this one the way it is and build another with a footswitchable 'boost' function - which is just going to be a 3pdt that adds two potentiometers to the circuit. One will be in parallel with r22 (which boosts the overall output), the other will be where r14 is now (which controls compression on the 'hi' setting of the dpdt on/off/on switch) and will switch between the low compression setting and the high (in this case variable) compression setting.

I'm going to name that pedal the "judgment day" overdrive - a play on Jon's 'snow day' monkier. here's the graphic I want to etch into it (I'm going to have to label it, reverse and scale it obviously but this is the photo I'm going to use):



I figure I can drill his eyes for LEDs - red one for the on/off and a blue one for the 'solo' boost function. I need to figure out labels for the 6 knobs - whether I want it to be straightforward, or go with a theme ('limit' instead of 'compression,' 'amplitude' instead of 'volume,' 'waveform' instead of 'gain,' and the labels for the khz/hz frequencies affected rather than 'bass' and 'treble')

So, as some (or even none) of you may remember, I posted recently about modifications to the flabulanche pedal based off of Jon patton's snow day overdrive.

I am pleased to report that I followed his advice and only added the "range" control from the omega circuit.



That's the photo covered with foam, because I wired the range control incorrectly - I accidentally have the 22k in line between the 33k and the 3n3 rather than in series with the 500KA control. Once I fix this I will post a photo showing the correct wiring for the additional range control.

Here's the completed pedal:



I used a 1590B, I think? Thanks to the rullywow breakout board it was enough to fit a battery in there too, should the need arise.

The problem was I originally biased all three transistors off of a battery, which was dying - so when I plugged it up to my 9v supply it hardly distorted at all. I pulled out the multimeter and q1 was biased at 13v, q2 at 13.5v, and q3 at 15.5v! It's possible someone would have liked the soud I'm sure, but it wasn't for me.

Re-biased to where q1 ran at 12v (halfway between 5v and 7v as per the omega circuit), q2 ran at 11.25v (may turn it down some when I get a chance, IDK), and q3 at 13v (as per the original instructions).

I took a demo video, but it was terrible - the volume from my amp overpowered the camera microphone so all you can hear is mic distortion unfortunately :/

I'm out of town until Monday, but here are my impressions from the 30 minutes I got to play it:

- Holy mother of god this is the best sounding boost/light OD pedal I've ever played... at the top of the gain control though it almost sounds like it's hard clipping, but at low/med gain levels it's like playing a combination of the EP booster and the SHO but with edge-of-breakup harmonically rich tones through a pedal
- Cleans up better than any pedal I've ever played... I hope this isn't due to the incorrect wiring of the "range" (bass roll-off) mod... Seriously it goes from AC/DC at 10 to completely clean at 7
- It has that jfet "detail/presence" that makes humbuckers sound like single coils and single coils sound like a piano. Even on completely clean/unity settings it's significantly more present. Again, I hope this isn't an unintended byproduct of the mis-wired "range" control.
- The compression isn't really noticeable from a listener's standpoint, but it's tasty if you're playing. I would like more aggressive compression but then again I used a mpf102 for q1. I notice it, for sure, but it's not even in the same ballpark as my bluesbreaker-derivative pedals or tubescreamer-based pedals. If you think of a boss SD-1 as being a 5/10 on the "compressed" scale, the "hi" position of the flabulanche is like... a 2 or 3. I'm definitely building another but I'm going to revert to something closer to the Aquataur compression circuit (adjustable 500k "sag" control) so I can get really compressed, sustain-y leads when I engage the "solo" footswitch (more on this soon)
- It makes everything really hi-fi... So much so that it makes my 1974x lite iib amp sound like I'm playing through a concrete barrier without it. Similar thing to many boost pedals but this has the additional benefit of sounding spectacular at low volumes.
- I used a mpf102 in q1, so for me, the gain goes from clean to AC/DC levels. I've read quite a few of Jon's posts where he speaks about how much gain the flabulanche makes, so for my purposes (which never foray into metal or anything resembling post-1980s rock n' roll) I figured a lower gain transistor (mpf102 vs. 2n5457) would bring it closer to what I want... boy did it ever.

So, my plans for a future pedal include two things - a separate footswitch to put a 100k pot in parallel with r23 (I think, it's one of the two that for the voltage divider on the output section of the circuit) and a 500k pot in place of the existing 220k "hi" control. The idea is that they'll work like a 'solo' switch, where I can increase the volume and compression for lead lines and still keep the pedal on all the time. Rather than have a set volume increase, a 100k pot wired correctly will allow someone to change the ratio of the divider network (100k in parallel with 10k = 9k ohm, so it would have a slight volume boost even at zero, but then again it's a solo switch so... yeah.) whereas the additional compression potentiometer can be added to the existing compression scheme, so you can have an additional boost/compression circuit without extensive modification.

Honestly, my biggest complaint is that this pedal isn't more popular... I took a chance seeing as it was a jfet-based OD with new and exciting compression circuit, but I would take that chance again 10 out of 10 times... It's really like having another amp attached to your amp lol.

FWIW, my modifications were:
- Q1: MPF102
- RS(Q1): 340 ohms (calculated value for mpf102 as per ROG)
- C2: 4.7uf (vs. 470nf)
- RS(Q2&3): 390 ohms
- Exclude R1
- 1M -> 3n3 -> 22k + 500ka potentiometer part of ROG's "omega" circuit wired to the input

Thank you much kind sir - I thought I downloaded from the website but I could have downloaded straight from Google.

Edit: yep, definitely got it off of Google - the file name is sparklehorn 1 rather than sparklehorn 2014. Thanks again for the help.

Brian,

Where do you get those mini potentiometer on the sparklehorn? The build doc has full sized ones listed (and a drilling template for 6 controls instead of