quote:

---

Originally posted by Little_Buster

I had seen a schematic for it awhile back i just cant seem to find itr know :/

---

quote:

---

Originally posted by Dr. Bob

quote:

---

Originally posted by Little_Buster

I had seen a schematic for it awhile back i just cant seem to find itr know :/

---

Hi Little_Buster

I have never seen this Sch. here on this forum.
The Tech guys, would all have it in our off site backups if we did.

You may have seen something on another forum or web site?

As CCSIM said, the circuits are very dissimilar, one being very simple & the other a lot more complex.

Perhaps it was something like an SD-1 to TS9 tubescreamer mod.
The SD-1 & TS9 are similar.

Laurie reworked an SD-1 into a Lovepedal Eternity, not to long ago.

If you do find an SD-1 to BD-2 schematic or mod sheet - we would all be very interested to see it.

Keep us informed with your search.

Regards Dr. Bob

---

quote:

---

Originally posted by MoonWatcher

Hi Little Buster -

As someone who's spent the better part of two years now addressing each "sub circuit" within the BD-2, I can tell you that it is completely unlike the SD-1. For that matter, it's also unlike most other Boss pedals.

The BD-2's closest ancestor is the OD-2, which I actually prefer, but it doesn't have the post level op amp boost stage. And the OD-3 is the next evolution of the BD-2, but really lacks the sex appeal, so it often goes overlooked.

The BD-2 is a great diamond in the rough, since it gets it's distortion from discrete jFET/BJT stages (two of them) that allow for slew rate limiting tweaks, as well as all of the typical HP filtering/gain adjustments that you'd get from an IC op amp stage.

The biggest problems with the stock pedal, IMO, are as follows:

- Too much gain in stock form, which overloads the post level op amp stage
- Too much bass in tone filtering after first gain stage
- A tone control without great flexibility
- Stifling clipping diodes in a discrete circuit that really doesn't need them if driven to more modest levels

Probably TMI, but that's what you're up against whilst dealing with mods for the BD-2.

If you want proof of what jFET's are capable of unbridled by clipping diodes, check out Catalinbread's Dirty Little Secret, which is basically a pair of mu amps with a third D.C. follower tranny for the even order harmonics.

And also check out runoffgroove.com for lots of great projects with jFET's. Whilst the circuitry in the BD-2 is a little different, it really is a great, quiet, stable (jFET's are tricky to match for gain and to bias by fixed methods) method.

Good Luck!

-MW

---