With Apologies to Jon Patton

[HKimball]

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

[lars]

Very nice. What kind of graphics did you put on this? I've wondered what inspiration builders would get from the name "flabulanche". (second thought, maybe we don't want to see that image)

[HKimball]

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')

[midwayfair]

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.

[TGP39]

I love when people challenge each other for the sake of trying to create a better (or just different) circuit. I have been reading a lot of old posts on here and it is damn exciting to watch Jon's (and many others) growth in this field.   I mean have you guys flipped through the many different member projects?  This community is filled with brilliant members.  I am so grateful to be able to learn from Brian and the forum members here. No circuit building school in the world gives this kind of hands on info. Thank you for that and keep them coming.....

Steve.

[HKimball]

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.

[HKimball]

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.