EffectsLayouts Pocket Comb Flanger

[spi]

This is the first BBD-based pedal I've made, and the first flanger I've owned that wasn't a part of a digital multi-effects.

I was interested in building a flanger but many of the PCBs for them seem to be odd: either they are stacked PCBs, or in large enclosures, or run off voltages other than 9v, etc. I picked this one pretty much because it (barely) fit a 125B without any other oddities. This is supposedly based on an Ibanez FL9.

So far it sounds pretty sweet, but I've really only played it enough to ensure it flanges and the knobs do stuff. There's 3 internal trimmers for bias, regen, and clock that I haven't even adjusted yet. It sounded great the first time it fired up, and I'm sure it will sound even better once it's fine tuned. The instructions don't offer any advice for tuning but I think I can follow the advice of the Madbeans Current Lover, which has the same trims despite being a different circuit.

I just used a label maker for the knobs for now, otherwise I'd forget what they are for. I may add art later if I get inspired.

I messed up the build at first, because I mounted the switch PCB upside down. I got most of the solder off using a sucker and some wick, but the board is still stuck to the switch so I ended up just dropping in a new switch and wiring directly.

 

[Betty Wont]

I’ve been curious about this one. I’m going to look deeper. Nice work

 

[spi]

I forget to mention there's one cap that is socketed because messing with it can adjust the max speed. For many modulations I think the max speed is too intense, so I wanted to be able to adjust if necessary. For now I've got the stock value, and it's actually pretty reasonable, so I'll probably leave it.

 

[Harry Klippton]

You're right. Flangers are purple

 

[Guardians of the analog]

Good job, it's a good flanger. It's really close to a boss fb-2. @blackhatboojum can also tell you which cap to change to lower the speed range.

 

[blackhatboojum]

Nice. I’ve built this one as well and it’s one of my favorite flangers. For clock frequency set all the knobs to minimum. Probe pin 2 or 4 of your mn3201 with something that measures frequency (o-scope or DMM) and adjust the clock trimmer to 40khz. For bias audio probe pin 7 or 8 of the mn3207 as you play through it or feed it a sine wave. Adjust bias trimmer to cleanest output. For the regen trimmer, plug the output into an amp. Have nothing plugged into the input. Set speed, width, and regen knobs to max. Adjust the regen trimmer to just below self oscillation. If you want to slow down your lfo speed, a 4.7uf bipolar cap in c25 is my preferred value.

 

[blackhatboojum]

I’ve been curious about this one. I’m going to look deeper. Nice work

The pocket comb is a good one. As Chris mentioned it’s very similar to a BF-2. I would describe the fl9 as softer and more mellow. The bf-2 tends to accentuate higher frequencies through its sweep, whereas this one has a flatter frequency sweep. Even with the regen dumped all the way out, it still sounds like a flanger. The Boss variant sounds more chorusy when you dump the regen.

 

[Betty Wont]

The pocket comb is a good one. As Chris mentioned it’s very similar to a BF-2. I would describe the fl9 as softer and more mellow. The bf-2 tends to accentuate higher frequencies through its sweep, whereas this one has a flatter frequency sweep. Even with the regen dumped all the way out, it still sounds like a flanger. The Boss variant sounds more chorusy when you dump the regen.

That is a very good description and kinda just what I think I want. Thank you!

 

[Betty Wont]

I think I’m out of flangers in my store so I just ordered a couple of these. I’m still looking for the clone theory flange mode sound with no noise. The description of this with the regen low sounds promising.

 

[blackhatboojum]

That is a very good description and kinda just what I think I want. Thank you!

You’re welcome . I’ll also add that when you crank the regen knob to max, the flange sound gets more vocal, almost wah like. Unlike the bf-2 where that gets really metallic and sproingy.

I think I’m out of flangers in my store so I just ordered a couple of these. I’m still looking for the clone theory flange mode sound with no noise. The description of this with the regen low sounds promising.

Right on! I hope you like it. I’m glad you mentioned noise because that’s another great thing about the pocket comb. Super low noise floor for a flanger. I run all of my effects in front of a screaming jcm 800 style amp and the pocket comb is the most quiet out of all of my flanger builds in front of my amp.

 

[Betty Wont]

You’re welcome . I’ll also add that when you crank the regen knob to max, the flange sound gets more vocal, almost wah like. Unlike the bf-2 where that gets really metallic and sproingy.


Right on! I hope you like it. I’m glad you mentioned noise because that’s another great thing about the pocket comb. Super low noise floor for a flanger. I run all of my effects in front of a screaming jcm 800 style amp and the pocket comb is the most quiet out of all of my builds in front of my amp.

I’m moist!

 

[spi]

Nice. I’ve built this one as well and it’s one of my favorite flangers. For clock frequency set all the knobs to minimum. Probe pin 2 or 4 of your mn3201 with something that measures frequency (o-scope or DMM) and adjust the clock trimmer to 40khz. For bias audio probe pin 7 or 8 of the mn3207 as you play through it or feed it a sine wave. Adjust bias trimmer to cleanest output. For the regen trimmer, plug the output into an amp. Have nothing plugged into the input. Set speed, width, and regen knobs to max. Adjust the regen trimmer to just below self oscillation. If you want to slow down your lfo speed, a 4.7uf bipolar cap in c25 is my preferred value.

Any advice for how to do this without a scope? I messed with the trimpots today... for a while I lost the flange, but I got it back to something reasonable, still feel it could be better though.

 

[blackhatboojum]

To get the clock frequency perfect you’ll need a multi meter that measures frequency or an oscilloscope. If you just set that trimmer around noon you’ll probably be pretty close to the service note spec. For bias, just use an audio probe like I already suggested. It’s pretty obvious audibly when you audio probe the output pins of the 3207 where the sweet spot is for bias. Find the point on the trimmer left and right when you turn it, where the audio distorts. Then just set the trimmer in the middle of those 2 points. The feedback trimmer just sets the maximum range of the regen knob. It’s not too crucial of an adjustment. Like I mentioned, plug the output of the pedal into your amp, short the input jack tip to sleeve, max out the speed, width, and regen knobs, adjust regen trimmer to just below the point the pedal self oscillates.