Two Byzantium Flangers (Boss BF-2)

MattG

Well-known member
I'm in a phase of trying to downsize and simplify my pedalboard, and came across this video: How To Get 6 Modulation Effects From a Basic Flanger Pedal Like The Boss BF-2 by Michael Banfield. So I researched the Boss BF-2, only to find it's no longer made (replaced by the digital BF-3). And then I came across two great Byzantium build reports: Byzantium Flanger by @blackhatboojum and Byzantium Flanger (Boss BF-2) by @MichaelW.

Edit: Also worth a look is PedalPCB Byzantium toggle festival (Boss BF-2) by @DGWVI.

I got a little overzealous, and built two at the same time. Why? Why not!

As has been said, don't be scared by the double stacked PCB business. Just follow @Robert's great low-profile parts guide, and it's really no harder than any other PPCB build (though perhaps a bit more time consuming).

I have very little flanger experience in general, so I didn't know what to expect. Both powered on correctly the first time, and seem to work reasonably with all the trimpots at noon. I then did the actual calibration process using @bean's Fraudhacker document as a guide.

The only thing that might be a problem is that, even with my "RES" trimpot turned all the way down, if the external "Regeneration" control is maxed, there is still a bit of (very slow) self oscillation. That is, I'll get a "whooshing" sound every second or so. If I back off the external Regeneration just a bit, it seems to go away. So I'm not sure if that's a "feature" or if I managed to misplace a component. I'm tempted to buy an actual (used) BF-2 for comparison. Both of my builds do this (though I literally built them at the same time, so any mistakes are likely in both pedals).

Whether it's slightly messed up or not, it certainly sounds great. It's definitely capable of lots of interesting sounds, I spent some time just having fun with it. I threw one of them on my board, I'll give it some use in the band.

A while ago I created my own microcontroller-based relay bypass scheme, and have used it on my last dozen or so builds. I made yet another revision to the PCB design, a surface-mount version for smaller size. It's just small enough to be squished into the enclosure with the two Byzantium PCBs. I actually got my wife to help me with the SMD work - she helped me paint on the solder paste. I "cooked" up three of those SMD bypass boards at once - she did one of them! And by "cook", I literally mean cook - I throw the board on a cooking skillet to hit it with heat from the bottom, then use an SMD rework tool to hit it with heat from the top and flow the solder paste. I think it looks pretty good, almost as good as robot-made SMD work.
 

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Looks good, congrats! For the trim pots: with the feedback control maxed you want to turn the RES trim up until you get runaway oscillations. You will know it when you hear it, it's super loud. Then you turn down the RES trim to just below that point. The other noise you are talking about might be helped by adjusting the clock trim. If you have a frequency measurement on your DMM you can set the clock for the factory setting and then adjust from there.

I have an original BF-2, it makes whooshing sounds even when you aren't playing. Most flangers do. I've been thinking of adding a gate like the one in the Ibanez CS-9 to a flanger circuit to address this. Flanger is my jam and the background whoosh is a pet peeve.
 
Looks good, congrats! For the trim pots: with the feedback control maxed you want to turn the RES trim up until you get runaway oscillations. You will know it when you hear it, it's super loud. Then you turn down the RES trim to just below that point. The other noise you are talking about might be helped by adjusting the clock trim. If you have a frequency measurement on your DMM you can set the clock for the factory setting and then adjust from there.

I have an original BF-2, it makes whooshing sounds even when you aren't playing. Most flangers do. I've been thinking of adding a gate like the one in the Ibanez CS-9 to a flanger circuit to address this. Flanger is my jam and the background whoosh is a pet peeve.

Thanks for that, it's super helpful! Nice to know the "background whoosh" is normal - knowing that, I'll play with the trimpots a bit more and see if I can further improve the sound. Although I'm super happy with the sound even now.
 
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