BSIAB II controls...

[critch]

I am about to add some extra controls to my BSIAB II design...
just some switches to switch between certain components/values, any suggestions?
i have read that by changing the C2(GGG shcematic) value,  i can change the pedal to a overdrive, does anyone know anything about this? and1 know anything about this?
I read that here: http://diystompboxes.com/sboxforum/viewtopic.php?t=32105&postdays=0&postorder=asc&highlight=bsiab+ii+mods&start=0
any other ideas?
thanks

[mojotron]

I am about to add some extra controls to my BSIAB II design...
just some switches to switch between certain components/values, any suggestions?
i have read that by changing the C2(GGG shcematic) value,  i can change the pedal to a overdrive, does anyone know anything about this? and1 know anything about this?
I read that here: http://diystompboxes.com/sboxforum/viewtopic.php?t=32105&postdays=0&postorder=asc&highlight=bsiab+ii+mods&start=0
any other ideas?
thanks

Yep, that's what switcing C2 on/off does - lowers the gain quite a bit. But, what I found is that the volume drops off quite a bit too - and I'm working on that. Here's what I have so far to address the issue of adjusting the volume so that there is not a huge drop in volume when you take out C2 on the BSIAB2.

Fix #1 - which is my favorite - is to use an AMZ MOSFET Boost (only with 2 different switchable resistors inplace of the pot R6 on the AMZ MB) in front of the BSIAB2 - in the same box switched with a DPDT - so that if you take out C2 on the BSIAB2 at the same time you reduce R6 on the MOSFET boost and this drives the now-moded BSIAB2 in a way that where you get a really high inpeadance on the guitar side of the circuit. This sounds awesome!! great overdrive - but you can push it as hard as you want with the MOSFET Boost. And when you go back to the un-moded-BSIAB2 the tonal change is along the lines of switching between a tight overdrive to a fatter full up distortion..

Fix #2 is to just switch in/out a resistor infront of the BSIAB2's C6 - and this works well, but there is still a bit of a volume drop when using the BSIAB2 as an OD. Actually what happens here is that the 2nd stage is forced into amplifying a much broader band of frequencies - which lowers the gain for humans and probably wakes up a few dogs in the area... so you could switch in a different value of cap there too.

Fix #3 - use the volume knob on the guitar. That works great too...

[critch]

thanks for getting back to me mojo...
I want to be able to get the original BSIAB II sound too btw, i just want to make the pedal much more versatile.
but do you reckon building a booster and putting it before the BSIAB II, and switching it on only when C2 is off will fix the low volume?
and do you know any other cool mods that i could implement using switches, and any other values that will be cool for C2?
thanks
PS. i do assume you mean bypassing C2 to get an OD, as opposed to a distortion, is that right?

[mojotron]

thanks for getting back to me mojo...
I want to be able to get the original BSIAB II sound too btw, i just want to make the pedal much more versatile.
but do you reckon building a booster and putting it before the BSIAB II, and switching it on only when C2 is off will fix the low volume?
and do you know any other cool mods that i could implement using switches, and any other values that will be cool for C2?
thanks
PS. i do assume you mean bypassing C2 to get an OD, as opposed to a distortion, is that right?

Right, you effectivly take C2 out of the circuit for an overdrive "neutered BSIAB2" sound. But, I really like the sound only with the boost infront of the BSIAB2 while working in this mode... You could just use the boost only when switched to OD mode as well...

What I would do is build the BSIAB2 keeping in mind that you are going to make some mods - use some sockets for the FETs as well as C2. Then, when you have the original BSIAB2 working the way you want - start building some experiment circuit additions that you switch in and out... In the end it's always what sounds best to your ears.

[critch]

ok, i get the OD thing, thanks...
and i am going to socket all JFETS. and can you socket resitors and capacitors?
and im trying to find out what mods people have made, so that i can add switches to switch between certain component values....for instance, for the C2 cap, i will add a switch to switch between the original cap, and no cap, and if i can get any other cool value suggestions, ill add them to the switch...this wont affect the sound will it?the signal going through a switch.
and can anyone suggest what other components i can add switches to, to bypass or change values?
thanks