Grounding Ge PNP Case?

Started by seedlings, March 07, 2012, 11:41:57 AM

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seedlings

Under what circumstances might it be beneficial to ground (or otherwise use in any way) the case pin on these GT313V PNPs?  Is it helpful like shielding a single coil guitar?



CHAD

R.G.

Inside a metal-case guitar pedal, it's of no redeeming value.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

seedlings

Quote from: R.G. on March 07, 2012, 02:42:16 PM
Inside a metal-case guitar pedal, it's of no redeeming value.

Case closed.  Thanks  ;)

CHAD

asatbluesboy

When my metal-case transistors touch the enclosure they kill my signal. Got me nuts when I built a Big Muff with BC108s, as it would mute whenever I closed the enclosure and I would think my skills were at fault--which is very likely.

I would never use that pin.
...collectors together and emitter to base? You're such a darling...

ton.

R.G.

The metal case on some transistors is designed to be a shield, on others it's connected to the collector. On transistors where it's connected to the collector, yep, it kills the signal. On ones where it's designed to be optional and NOT connected to the collector, you can connect it to ground if you like. This is useful in some specific high impedance and RF situations. It's not generally useful in stompboxes even if you do have the kind that can be grounded.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.