Mudbunny C12- grabbed a polarized tantalum cap- oops?

[ElCapitan]

Hi everyone, new to the forum. I did a search on this and didn't find the exact answer to this question.    I'm doing a P19 style build on the Mudbunny PCB, and it looks like for C12 I grabbed a tantalum.   It's polarized, and my understanding is that it's ok to use there, however I need to determine where to orient the positive lead.  Any ideas?   

[m-Kresol]

Hi, welcome to the community.

If I had to choose, I'd put the positive leg to the right, i.e. going to the base of Q4.

I hope someone can verify.

[ElCapitan]

Thanks for the response!   Would you be able to tell me the reasoning behind that choice?   . Just trying to learn. 

[m-Kresol]

sure thing.

R20 connects the right side of C12  to the 9V supply grid. Together with R21 it forms a voltage divider setting the base voltage (DC). I'm only rough guessing here, but I'd say that this should be around 2V (~400k/100k should give a voltage drop of approx 4/5 of the supply). So there will always be DC voltage on the right side of C12. On the left side of C12 facing the tone pot, I'd assume that the voltage swing would be lower than that.

you could make sure and solder everything in except for C12 and measure DC and AC voltage on the left pin and right pin. Whatever is higher, is the way to face the positive leg.

alternatively you could just post here asking if someone can spare a film cap.

[ElCapitan]

Wow.  Great answer.   Thanks so much.  I've been an assemble by numbers guy for the most part but I can see how running into problems can be extraordinarily instructive.   I think I'll do just what you recommend as far as the testing goes. 

[m-Kresol]

You're welcome. You'll get there. That's how most of us start.

"Hey, that doesn't look to complicated. I bet I can build that."

I think many of us don't leave the paint by numbers approach. As long as you learn how to troubleshoot or have a community like this, it isn't necessary. However, it is very rewarding to get deeper into the world of electronics as you will be able to do more complicated stuff like designing your own circuits.

[ElCapitan]

Well, I used my multimeter in both Dc and ac, and it Looks like it's equal on both sides.   I'm going to install it the way you've suggested, and see how it goes. 

[ElCapitan]

Worked a treat.   Pretty much an amazing pedal. 

[m-Kresol]

good to hear. Let's see a build report

[ElCapitan]

Will do!