[sdiy] Mixed-signal problems (dsPIC digital delay project)

Tom Wiltshire tom at electricdruid.net
Thu Jan 26 18:03:31 CET 2017

Ok, I'll give it a try on the board and see if it helps. Thanks. A pair of 100n ceramics from the op-amp power to the virtual ground, right?

But that's trying to limit the effect of the noise on the 9V rail, isn't it? Is there any way I can stop it getting there in the first place? Is that what the inductors going to the regulators do - stop noise coming back from the far side of the regulator?
I think I need to understand better where this noise is coming from and why.

On 26 Jan 2017, at 16:32, yo at vacoloco.net wrote:

> I totally missed that, too busy looking at PSU problems and grounds.
> yes, decoupling caps (but they'll need to be to your virtual ground).
> On 2017-01-26 16:11, Jason Tribbeck wrote:
>> You don't seem to have any decoupling capacitors for the op-amps.
>> And I would also suggest small inductors (or even ferrite beads) going
>> from the 9v line to the input of each of the regulators.

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