Boss BF-2 Flanger: Anyone done the Wampler mod and/or calibration?

[Snufkinoob]

There are 11 mods listed in the Wampler book:

6 of them quieten background hiss - Just cap replacements, not sure if the value is altered or just the cap material (metal film). Do they all need doing or might just one or two do the trick?

2 of them "Get rid of the boxy sound" - No idea what this means. I'm fairly happy with the sound too, so don't want to try this unless there's a definite difference.

1 gives more depth - This is a cap value replacement. Any overall tone difference or just more available depth? Worth it?

And 2 aren't really mods, and just say "tweak the trim pots". But on that note, I came across a few websites that cover calibrating the pedal with an oscilloscope. Has anyone actually done this? If the "ideal" settings are audible I'm curious to know if it can be done by ear.

Or if anyone knows of any other mods that are worthwhile, that'd be great. I've done some googling and came up with a few forums topics about seemingly simple mods, switchable caps to change this that and the other, but there's never any detailed comments about what various mods actually do and how they sound.

[Snufkinoob]

Bump. Finally got round to doing most of the mods.

Metal film caps to reduce background noise works, and "The boxy sound" mod cleans up the overall sound quality. It's basically replacing two 4.7nf caps with 10nf caps. The only side effects is that it seems to make the Res/Regen and Manual controls more subtle when the depth up high. But once you back off the depth, the sweep of those controls becomes more audible as it was before.

I've not tried the depth mod, but the 'spaceship' mod also mentioned in the Wampler book isn't all that great. Just makes it sound over the top all the time.

[Mark Hammer]

"Boxiness" rests primarily in the regen loop.  Reducing the value of the caps in the feedback loop (C20, C7) trims the bass, so that the bass is not overemphasizd at the bottom end of the sweep.  Just to be precise, those caps are 47nf stock (.047uf).  Reducing both to 10nf (.01uf) will raise the low-end rolloff by a little more than 2 octaves from where it is now.  If that doesn't work for you, try 8n2.

[Snufkinoob]

Ah right, just misread the 47nf. It's a nice balance actually, not too thin, just 'clean' sounding. I might try the depth mod on a toggle switch next.

[Mark Hammer]

Another useful mod is to lift the clean signal at the mixing stage (R28).  Unfortunately, the switching method Boss uses simply lifts the wet signal to cancel the effect.  If one lifts the dry signal and then hits bypass, you end up with nothing.  One needs a different bypassing method to accomplish vibrato.

[duck_arse]

if it's a boss, it'll have a bypass flipflop, no? you can add a fet to the feedforward line between ?R28? and the output side opamp half, and connect the gate via a spdt (like they do bypass) between V+ (flange) and the Q9 collector (vibe).

at least, I've done this on the bb for the cs1/2/3 I was hacking a while ago.