BSIAB Build 2

[petemoore]

I'm wondering where I could find the BSIAB 2 schematic.
 Couldn't find the first BSIAB 'lite' I was working on long ago. Built another, a BSIAB.
 Started off building a Mini BOoster, worked so great I decided to finish a complete BSIAB.
 I left sockets 'everywhere, so I can plug gain increasing/decreasing resistors and caps in. Also put sockets on the TC except 2 caps.
 I have to concur that this thing is the closest thing to a Cranking Distortted Marshall sound I've ever heard 'in a box'. Yupp, amazing how Present the Marshall Grind tone is on it.
 Looks to be plenty of places to add an SPST or better switch to control gain/voicing.
 Tried a bunch of mods, circuit sound just great as shown. I'm preferrning J201's in it...tried MPF102's and 2n5952's, but they didn't perform as well IMO.
 I'm not done with this one, the minibooster sounds so good alone, and the lower gain settings so nice, I'm thinking of adding an alternate 1rst Jfet Stage of some kind to have a Med, and High gain sound, each 'set-uppable' so 1 switch hit makes the transistion.
 I build the MB...debugged it, tested it, sounded just great, distorted a little with the gain mods...cool/
 Then I built another MB [long board I used begged for it], debugged and tested both MB's seriesed...WOW...really great Distortion, almost no need for TC.
 Then I added the last Jfet source follower and TC...totally great circuit.

[RDV]

GGG

RDV

[mojotron]

Since everyone seems to like the BSIB2 I thought I would check it out.

In my first build, I used film 120pf and 220pf caps instead of 150pf and 250pf ceramic caps - they were the only film caps I had on hand around that size... The sound is really nice - lots of dynamics. But, I'm not getting as much gain out of it as on the end of the sound clip on GGG, also I have the 100K trim pot at about 40K.

I always try film caps if I have them - have most of you guys used ceramic caps on this circuit?

If you have tried different caps - for the pf ones - how was the sound difference?

Also, I can drive the moderate overdrive into the amp really hard - which is pretty nice if I have the amp set to just breaking up - great blues sound...

[MartyMart]

Since everyone seems to like the BSIB2 I thought I would check it out.

In my first build, I used film 120pf and 220pf caps instead of 150pf and 250pf ceramic caps - they were the only film caps I had on hand around that size... The sound is really nice - lots of dynamics. But, I'm not getting as much gain out of it as on the end of the sound clip on GGG, also I have the 100K trim pot at about 40K.

I always try film caps if I have them - have most of you guys used ceramic caps on this circuit?

If you have tried different caps - for the pf ones - how was the sound difference?

Also, I can drive the moderate overdrive into the amp really hard - which is pretty nice if I have the amp set to just breaking up - great blues sound...

I think your "drive" difference will be more to do with the J201's all being slightly different, I've had huge differences (hfe) and always try several out.
I got a big bag of silva mica caps on an Ebay deal 10 months ago, so have not used any "ceramics" in a build yet !
I've read that in an overdrive ceramics can add some "grit" but at this high gain, i'm happy to use mica's and metal film throughout, my BSIAB II is not noisy at all  !

Marty.

[petemoore]

By using RG's noisless biasing technique. Since I had the 10k divider resistors already on the Mini Boooster [and a 4m7 to gate of top Fet], I figured try out that divider on the second stage, must work the same, perfectly or just great, I'm glad I tried that.
 One way to up the gain is use the 1k [or less] between the Q1 D and the Q2 source...reads at GEO's 'mod your own Mu Amp...many of the notes in the article I applied to this build.
 Yupp amazing how smoothly it sounds like a big 'ol tube amp with a DIST+ going in it [or something]...very well defined, dynamic, and the other 1000 '+' words I could type about it.

[mojotron]

...J201's all being slightly different, I've had huge differences (hfe) and always try several out.....

Oh ya..... I usually only worried about that with Ge BJTs.... I will check this out... Thanks!

[mojotron]

By using RG's noisless biasing technique. Since I had the 10k divider resistors already on the Mini Boooster [and a 4m7 to gate of top Fet], I figured try out that divider on the second stage, must work the same, perfectly or just great, I'm glad I tried that.
 One way to up the gain is use the 1k [or less] between the Q1 D and the Q2 source...reads at GEO's 'mod your own Mu Amp...many of the notes in the article I applied to this build.
 Yupp amazing how smoothly it sounds like a big 'ol tube amp with a DIST+ going in it [or something]...very well defined, dynamic, and the other 1000 '+' words I could type about it.

Cool, I will check this out. I found that I had a short, once I fixed that I got pretty good gain (drives better than before...). I played with the caps that I had in there with others and found that a 150pf ceramic and a 220pf film cap made a for little more oomff... very mean!! This is the first pedal where I got a really decent Marshall punch out of it w/out a 4x12 cab... It's instantly one of my favorites.... I have this tone circuit I'm going to work into it to get a 3 band eq. But, I am going to work on the gain first - currently I am getting about the same gain as I have hear in sound clips.
Thanks!

[mojotron]

I played with the caps that I had in there with others and found that a 150pf ceramic and a 220pf film cap made a for little more oomff... very mean!!

Yep, I just rechecked this while I was building some other stuff... I like the 150pf cap (as in the schematic) and sub out the 250pf with a 220pf film cap.. It's a minor change, and the change in sound is very slight, but it's a little more authentic to my ears - for what it's worth...

Thanks for the tip on the GEO site petemoore, the stuff on using RG's biasing technique is really interesting - the kind of stuff that makes me want to experiment a bit.

This is one of the better pedals I have heard.

Anyone tried the Blue Magic off of GGG?

[Urban Osterman]

I'm wondering where I could find the BSIAB 2 schematic.

Hi Pete
Have you tried this link

http://www.generalguitargadgets.com/
or
http://www.generalguitargadgets.com/diagrams/bsiab_2_sc.gif

Thats where I got mine from
I built one and
it sounds very good.

/Urban

[petemoore]

Thanks Uberman.
  Thanks to Ed Guidry for posting the BSIAB and BSIAB 2 schematics !!!
  Great sound, I may try the BSIAB 2, soon !!