Rather Homely BSIAB2 Build (With Homely Pictures)

[sta63bmx]

I was rooting through junk equipment when I noticed two matching little blue boxes.  They were originally each a VARACTOR BRIDGE PREAMP!!!!! and probably did something important.  But that was a while ago.  I thought they would make cute little pedals for something simple.  I was thinking Microamp, but I really wanted to build a BSIAB2.  So I put it in there.  Here are a couple pictures.



I could only find brown and black, making this about the ugliest VH paint job ever.  I had time to let it dry while I soldered everything together, though.  The knobs were salvaged off something else.  They're nice and beefy.  But they take up a lot of real estate.



More of a top shot.  The light is high-intensity green, not that I can see it here.  The pliers are to make it turn on.  The blue and black woulda looked better alone, in retrospect.



See how the holes don't line up?  It had a hole in either end for something else.  Some kind of high voltage BNC screw-on looking thing on one end and uh...something else on the other end.  They were already the right size for input jacks and cleared the bottom plate, so I used them.



That's not an envelope of drugs, it's the PCB.  It was kind of cramped trying to make room for the battery, so I did a high quality manila insulation job and stuffed it in there between the pots and switch and everything.  These boxes are made by Pomona.  They're cast aluminum, but the walls were thicker than the Toadworks boxes.  These boxes are about 4"x2.5"x1.5, kinda like a shorter, taller MXR box, I guess.  There turned out to be plenty of room for the battery after I tucked the PCB in there.  It took a little bit to figure out how to put it in there.  The PCB took up the whole height of the box if I tried to put it vertically and then I couldn't pass wires around it.  I would have preferred that.



I put another pedal together like this, too.  I think I like using the ribbon cable for the pot wiring and stuff.  It packs really easily, and it kind of keeps everything compact.  The wiring is pretty sloppy because I like to leave it long enough that I can pull the board out and work on it if I want.  When I'm done I just kinda tuck it all in there, where it can probably act as a nice antenna.  I have a stash of it, so it works.  I just pull off what I need and use the rest of it for single wires and stuff.

I built this pedal exactly stock.  To tune it, I just gave it a 1kHz sine wave and went back and forth until it was as loud as possible.  There was one spot where it got loudest.  I was doing that with the guitar, but between strumming and turning and...well, you get the idea.  This pedal is a great rhythm pedal.  It was like AC/DC in a box.  Not a ton of harmonics to pinch out of it like a TS, but it was a lot more robust sounding.  It really does sound more like a cranked amp than my other pedals.  I really liked the sound.  I wish it would have been a little louder.  It's well above unity gain, but doesn't seem to have as much level gain as my TS or a Microamp.  The tone knob really seemed to suck away volume when it was down.  I ran it almost full on.  I am going to build another one and try some of those mods Mojotron posted.  I'll just use this one in the meantime.  I really like it.  I used two J201's and the rest 2N5457's like in the GGG files, built from the GGG layout.

[syndromet]

Ohh!! Tht is so cool!! That pedal just screams "I don't care what it look like, as long as i sounds good", and that sounds like a typical Van Halen thing to say...  What do you think of the circuit? I was mabe planning to do this one myself.

Like the bloodspill on the bottom picture, btw.....

[sta63bmx]

I think that's actually my kid's Looney Tunes red jello that has dried on the table.  I wish I was that metal, though. lol  I think the circuit is great, especially for rhythm and rock and roll playing.

1. Not enough gain for metal by itself.
2. Not a ton of compression or sustain.
3. Harmonics and pinch harmonics don't really seem to jump out.

BUT.

1. Sounds like AC/DC in a box.
2. Sounds more like a cranked amp than any other pedal I've heard.
3. Really muscular sound, really full, and kind of transparent, lets your playing come through.

[RaceDriver205]

Try boosting the input. Build an easy AMZ Mosfet Boost if you dont have one.
I found that with the Boss DS-1, it was wussy and nasty sounding. Then I boosted it and it sounded NICE.
Ive heard the BSIAB2 used at a much higher-gain sound than mine does. My pickups must just be weak.

[Ed G.]

I think that's actually my kid's Looney Tunes red jello that has dried on the table.  I wish I was that metal, though. lol  I think the circuit is great, especially for rhythm and rock and roll playing.

1. Not enough gain for metal by itself.
2. Not a ton of compression or sustain.
3. Harmonics and pinch harmonics don't really seem to jump out.

BUT.

1. Sounds like AC/DC in a box.
2. Sounds more like a cranked amp than any other pedal I've heard.
3. Really muscular sound, really full, and kind of transparent, lets your playing come through.

Something's not right. It has lots of compression and sustain through a clean amp with even low-powered pickups. It's not chunka-chunka palm mute riffing metal, but it will get you the Van Halen sound (I used it today at band practice and nailed the tone on "Jump" including the solo) so that should give you an idea.
Harmonics and pinch harmonics are this pedal's thing.
I'm convinced that something's not right or maybe there's a bad fet or something in there. I think maybe the Q5 isn't tuning in right. Try sticking a J201 in Q5, for some reason it tunes in real easy in that position although I find it can be overcompressed.
If you can take some voltage readings, post them or compare them against the voltages at the GGG site.

[sta63bmx]

The master!  The legend!  I am humbled that Ed Guidry himself would look in upon my build.  I'm afraid the box doesn't do this particular build justice.

Since I have evidently done something wrong, I will take another crack at this circuit.  I'm gonna be travelling for a week, but when I get back I will check the voltages on this guy.  I ran out of sockets and couldn't socket the FETs, so it's possible that I burned one out.  I usually solder pretty fast, but I use a larger iron than I should, maybe.  Weller WTCPT represent.  I will see if the values are off somwhere.  If I *did* burn a fet, would it just be kind of like losing a gain stage?  I guess that would depend on which one I toasted. 

I am just going to build another one from scratch, I think.  If I *did* burn something in this pedal, I'm just going to leave it and build another one, rather than risk "fixing" this one and losing the sound it has.  This particular build doesn't quite have enough gain for VH style tones, but it sounds exactly like Angus and Malcolm Young.  In the garage, I am running this pedal into an Ampeg Gemini with a single 12" Jensen reissue.  The amp has 7591s and is set at decent volume but it's just a plain old tube amp.  The guitar is a Yamaha SBG-500 with a Dimarzio Dual Sound in the bridge and (we think) a Super 2 in the neck.  It might be a PAF, but should be a Super 2.  At any rate, this pedal doesn't sound super distorted, it just sounds incredibly "loud".  It completely nails the old AC/DC sound.  Also sounds like "Working Man" by Rush and "Mississippi Queen".

I had my cousin (our other guitarist) come over to play it today.  I have also built a Distortion Plus and a pair of TS style pedals.  He plugged it in and we cranked it up, and after about five minutes, he goes "I think this is the best thing you've built so far."  I thought so too, but I didn't say it before he did.  We went over to the music store to hassle the sales staff, and it was rated "sounds way more like a cranked amp" than the TS-9 reissues.  It got really good reviews.  This particular pedal came out having less gain than a TS-9, if that says anything.  I'm assuming that means something is wrong from what I've read in the thread.  However, I can't bear to change anything with this pedal now!  I'll just build another one.

Evidently you're telling me it gets better than this.  I have a hard time believing it, since I've never been as happy with a build as I was with this one.  Listen to the intro to "Walk All Over You" by AC/DC.  Where he hits that G chord and lets it ring out hard and you can hear it bloom and then hits the D and you hear it ring, this pedal build sounds exactly like that.  If this is messed up somewhere, I'd like to know where, because this pedal has balls.  Just about every pedal I've played has been disappointing on some level or it always really sounded like a pedal, even if it did sound good.  This one, unreal.  Even when I turn the drive down on my TS clone for rhythm work, it still kind of has that "I'm a fuzzy diode clipping thing!" sound going on.  This has that hard edge of an amp cranked to 6-7.  I will record some sound samples in about a week and a half, and if you don't think it sounds just like vintage AC/DC, then you are completely wrong.

And I will try again with this circuit and socket the FETs next time.  I can't wait now!  Does the real thing get the sounds I'm describing *and* the higher gain sounds?

[RaceDriver205]

I would seriously try boosting the input - can make a big difference.

[Ed G.]

Turning down the BSIAB can get you that AC/DC type crunch, but maybe you stumbled onto something accidentally that does it better, who knows?
If you build a second one and it comes out all right, you can compare the two. Built correctly, the BSIAB2 has lots of sustain. I think the sound you are in love with is the sound of fets overdriving, which is closer to the sound of tubes, IMO, than diodes can be. I've experimented with some lower gain fets, and they can produce a dedicated 'overdrive' pedal that is suited for blues to the ac/dc crunch because of the added headroom. Some people use 2n5457's throughout the pedal and it lowers the gain a bit, but there's still enough gain for leads.