could someone check this chorus layout quick, thx

floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

Found this 'one-chip chorus' made with a pt2399 you may have heard about but the threads these layouts are attached to meander wildly into issues people may have found and my knowledge of electronics is still relatively embryonic at this point. could someone who knows their s*** have a quick scan. I would just breadboard it but im waiting for more in the post

There's two; what I believe to be the original:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

And a cleaner layout:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

I'm a bit confused by them because I believe pin 3 & 4 should always be grounded on the 99's and I can't find that in the layouts, i might be being a dumbass tho, thanks

Grumble · Posted: Tue Nov 17, 2020 11:48 am Post subject:

You are correct, pin 3 and 4 should be both connected to gnd (analog gnd and digital gnd) that looks like an error in both the layouts.

Edit:added some words

ElectroSmash - PT2399 Analysis.pdf

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flagada · Joined: Dec 15, 2016 Posts: 39 Location: Amsterdam

In the upper lay out, 3 and 4 are grounded, aren't they?

EDIT: now looking a bit better, 4 does not seem to be.

khakifridge · Joined: Jul 15, 2014 Posts: 27 Location: UK

Pins 3 and 4 are connected internally by a low-value resistor. Many schematics don't show them connected for this reason, including the original schematic by "anchovie" from which these layouts are derived.

Real-world experience suggests YMMV. It's easy enough to bridge the pins with solder or a small link if you find it's needed.