Fromel mods... Anyone have experience, particularly the Boss HF-2 Flanger mod?

[bhyatt1]

Subject line says it all... I've ordered the kit to mod mine, just wondering if anyone else has used this or any similar mods from Fromel. Maybe the BF2 mod (nearly similar)

[flanagan0718]

I did a few mods to a bf2 a while back. I'll see if I can find the documentation.


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[VanDerchuck]

I fixed one once that someone else had done. Stupid connection at the pot that ohmed out fine. Pulled the rate led and it worked. I still have the directions in paper form somewhere. Not sure where. What was your specific question? DM me if you feel more comfortable.

[bhyatt1]

My issue is that I've completed the mod... All works fine, however when I wired up the LED as directed, only the blue light would work. So I kept messing around with it and somehow got the light to be green, and then I broke a leg off =( The thing sounds AMAZING and I use a true bypass looper so it's no biggie but I would like to order a new LED and figure out how to make the damn thing work right with the color change and flashing with the rate.

[VanDerchuck]

Bi-colored LED's are easy to find. Getting that little bit of the mod to work eluded me to. I ended up just wiring one side as it had been before and leaving the second color lead covered in heat shrink. Everytime I tried to hook that other lead to the depth pot the pedal would go silent. But the LED's worked. My first thought was that it must have been a bad LED, and my second thought was f'it. It sounded really damn good.

[bhyatt1]

Now, I replaced the led and the blue flashes at the rate... but it flashes in bypass and a use a true bypass looper so if I could just get it to flash only with the pedal on I'd be happy. Gonna mess with it more later...

[lars]

All the mod kits I've seen ignore the biggest problem with the BF-2 and HF-2:  the BBD itself. The BF-2 especially suffers from having a BBD chip with way too many stages, and naturally it sounds metallic and more like a chorus pedal with some clanging wind chimes. Those sounds can be useful, but you probably want more classic tape flange type sounds.
No amount of tweaking resistors, caps, or op amps will achieve that with the Boss flangers.
The best mod for a BF-2 or HF-2 is to change the BBD to an MN3209, which operates closer to the correct delay range for classic flange effects. No need for tweaking, overclocking, buffering, or spending hours coming up with a solution that Panasonic already engineered about 25 years ago. Realistically, even an MN3206 at only 128 stages would work as a good flanger BBD. According to Eventide, "As a practical matter, useful flanging occurs in the delay range of 50 microseconds to about 5 milliseconds, and devolves to a doubling effect after about 15 milliseconds." Look at the respective datasheets and it becomes clear why the MN3007, MN3207, and MN3204 don't make good flanger BBDs. Yet, that's what 90% of the flangers on the market used.