BSIAB2 and my Sunday woes.

[Bobbytouche]

Good afternoon!

This is my second pedal build, but let's pretend it's my first as my last was over a decade ago. I'm building the BSIAB2 from GGG. I've made a few corrections and so far I'm really enjoying it.

I've removed the 82k resistor from the tone stack for a bit more bass per the GGG mod notes  and got good results. Still planning on adding a 0.22uf capacitor parallel to the r15 resistor. says to "solder tack the capacitor across the resistor". Does this mean to attach the legs of the capacitor to the legs of the resistor?

I've also added the contour pot and agree with the entire internet that it was a good idea.

Here's where I'm at...

I've traced my wiring and am 95% sure it's correct. However when I switch the pedal off it only seems to deactivate the gain. I can still control my overall volume from the pedal, which is a bummer because it's coloring my sound quite a bit and I really like the clean on my amp.

Next up, the gain is sooooo close to the highly sought after Brown Sound, but it seems to have a top end "fizz" (which perhaps is a part of the brown sound, but maybe not so strong) which from my very newb uderstanding couuuuuld be something to do with biasing the trim pot to the recommended 4-4.5v. While the adjustments do have a huge effect on the sound quality, the fizz is not effected. Again, it could just be part of the design intentionally.

Thirdly... DOES NOT PLAY WELL WITH OTHERS... Nooe. Not one bit. I put it in my pedal chain and my overall sound took a nosedive. May have something to do with the afformentioned bypass issue.

Anywho, thanks a lot everyone and, by all means,  any recommendations to get the most out this pedal would be greatly appreciated. In the meantime, I'll keep looking around here. Definitely a wealth knowledge for this pedal specifically.

Cheers!

[Bobbytouche]

P.S. The best version I've heard is by Dazatronyx out of Australia. He charges about $200 for one prebuilt and while don't want to lose him any money I'd like to try to recreate his build (he has a video on Facebook of him building one. I'll need to watch and take notes) but is anyone here familiar with his circuit? I may consider a follow up build to this one.

[GibsonGM]

Welcome back, Bobby!

"tack across the resistor" tack it right to the R's legs, yup! 

Your thought on the bypass being screwy is correct..go back over every wire connection and solder joint!  It should be true bypass and not have any effect on anything before or after it, when off...sorry, crunched for time or I'd go over it via your pic...

Strangely, I've never built a BSIAB2!  So no other suggestions, sorry, but others will have some.  Tube distortion, esp boosted, is my thang  

[GGBB]

I've traced my wiring and am 95% sure it's correct. However when I switch the pedal off it only seems to deactivate the gain. I can still control my overall volume from the pedal, which is a bummer because it's coloring my sound quite a bit and I really like the clean on my amp.

Next up, the gain is sooooo close to the highly sought after Brown Sound, but it seems to have a top end "fizz"

It looks like the switch is wired fine, which suggests the switch itself may be faulty. Check the switch terminals with your meter - make sure open and connected on each pole are correct.

I found the BSIAB2 to be excessively bright for my tastes - maybe that's what you are hearing as fizz. I ended up building a BSIAB2 - Wampler Pinnacle hybrid - I found the tone stack in the Pinnacle much better and it smoothed out the top end quite a bit.

[Bobbytouche]

The 3pdt was the problem. Threw a new one in there today and problem solved!

You may be right about the brightness. I'll be modding here and there. Pretty happy so far though.

[Bobbytouche]

Welcome back, Bobby!

"tack across the resistor" tack it right to the R's legs, yup!

May be a silly question, but I only have electrolytic capacitors in that value. Would one of those work?

[GibsonGM]

"Still planning on adding a 0.22uf capacitor parallel to the r15 resistor. says to "solder tack the capacitor across the resistor"...
"I only have electrolytic capacitors in that value. Would one of those work?"

POINT 22 uF electrolytic?  I'd expect that to be a poly or something? 

Little confused which one is called for.   22u would be overkill, .22 would be a treble boost kind of thing.  Assuming a .22 is called for, don't think you'd have that one in a can!

[Bobbytouche]

"Still planning on adding a 0.22uf capacitor parallel to the r15 resistor. says to "solder tack the capacitor across the resistor"...
"I only have electrolytic capacitors in that value. Would one of those work?"

POINT 22 uF electrolytic?  I'd expect that to be a poly or something? 

Little confused which one is called for.   22u would be overkill, .22 would be a treble boost kind of thing.  Assuming a .22 is called for, don't think you'd have that one in a can!

[antonis]

If your 220nF electro is polarized, place it with its negative leg towards GND..

P.S.
If we refer on the same GGG schematic, R15 is Q5 Source resistor..
By bypassing it with 220nF cap, we get more TREBLE..
(not Bass..)

[Bobbytouche]

Yeah, I got it from the modification notes on their page.

http://www.generalguitargadgets.com/pdf/ggg_bsiab2_mods.pdf

[GibsonGM]

I have been DIY electronics for 20 years; I've NEVER seen or heard of an electrolytic cap smaller than .68u.   

In any case, as Antonis said.  In that position as source bypass cap, an electro won't make any notable difference in terms of noise etc.  Some people use a larger value for 'full bypass' which would allow full gain of bass frequencies as well.

[GGBB]

I have been DIY electronics for 20 years; I've NEVER seen or heard of an electrolytic cap smaller than .68u.   

Tantalum?

[antonis]

https://eu.mouser.com/Passive-Components/Capacitors/Aluminum-Electrolytic-Capacitors/Aluminum-Electrolytic-Capacitors-Radial-Leaded/_/N-75hqw?Keyword=100nf&FS=True

[GibsonGM]

 

I didn't mean they don't exist, only that I personally have not seen less than .68u electro     I got it once, a long long time ago, in a grab back of Radio Shack electros. 

Good heavens, why would anyone use one outside of a power supply, when poly caps are so readily available?

Yes, I know of tantalums - do we consider them 'electrolytic', do they use an actual electrolyte?  I've only ever used an electro where you HAVE to, power supplies, due to their 'poor qualities' in the audio path. 

[Bobbytouche]

I didn't mean they don't exist, only that I personally have not seen less than .68u electro     I got it once, a long long time ago, in a grab back of Radio Shack electros. 

Good heavens, why would anyone use one outside of a power supply, when poly caps are so readily available?

Yes, I know of tantalums - do we consider them 'electrolytic', do they use an actual electrolyte?  I've only ever used an electro where you HAVE to, power supplies, due to their 'poor qualities' in the audio path.

I had gotten a big kit of components on Amazon (resistors, caps, led's, diodes, etc.) and unfortunately is didn't have any .22uf film caps. But I pulled the trigger and ordered a kit with a bunch of different values including this one. I thought using the electro cap seemed a bit strange. If you can't tell, this is all Greek to me. Lol.

[GibsonGM]

For small values, I've just always understood the poly type is better. No 'drying out in time' problems, lower ESR, may be smaller physical size, less distortion (tho there are arguments on how critical that is) and so on.   A big-ass kit of the poly's won't do you wrong!   You WILL use them.   

You use poly (or other non-electro types) a lot when you are say, customizing a pedal and want to see what different size input caps do to the tone - you may want to try 5 different values and so on  

[GGBB]

Yes, I know of tantalums - do we consider them 'electrolytic', do they use an actual electrolyte?

I only know this because I looked it up once. Yes - they are electrolytic. https://en.wikipedia.org/wiki/Tantalum_capacitor

Electrolytes used in capacitors can be liquid or solid - I think the "garden variety" tantalums use solid. So in general they are far more "stable" than Aluminum and they also have much lower ESR. But unfortunately they apparently do not tolerate reverse voltage very well which aluminum does better. So you can't always use a tantalum in place of an aluminum.

But - back to the point - for 0.22 we can easily use film.