madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: G.G. on September 18, 2012, 02:51:09 PM

Title: Cosmopolitan pinouts
Post by: G.G. on September 18, 2012, 02:51:09 PM
Hey guys,
I've managed to confuse myself on the Q2 pinouts on the Cosmo.  I'm using a board etched by the "Bean hizself, so looking at the Layout Diagram in the Cosmo build docs it appears that the emitter goes to ground, which would make it on the left side in the Layout and therefor the Transistor tab would go on the left as well. I'm doing some debug on my build, and have seen Q2 oriented different ways in various build reports so I just wanted to confirm, 'cuz I'm a knucklehead.

thanks muchly,
Gray
Title: Re: Cosmopolitan pinouts
Post by: Bret608 on September 18, 2012, 04:23:40 PM
What transistor are you using? I posted almost this exact question over in "General Questions" last week. Folks were able to point we in the right direction pretty quickly. I'll do my best to help if I can!
Title: Re: Cosmopolitan pinouts
Post by: G.G. on September 18, 2012, 04:28:14 PM
I'm just using a metal can BC109 like in the build doc.

thanks!
Gray
Title: Re: Cosmopolitan pinouts
Post by: Bret608 on September 18, 2012, 05:00:58 PM
If your BC109 has the little tab on the side, you should have that facing "southeast" if you're looking down at the component side of the board. (I hope that makes sense! I realize we're talking about a pedal PCB and not a compass... ;) ) I believe the tab denotes the emitter. That would basically follow the build doc. I did that with my BC108 (same pinout as BC109) and it worked out fine.

I know what you mean about this getting confusing. I have a plastic-package BC149c that I may try in the Cosmo at some point, and it would need to go the opposite of what appears in the build doc (flat side facing north)! Anyway, good luck and let me know how it works out.

Cheers,

Bret