I don't have a scope unfortunately. And I tried that, but it did the same thing. I think I just can't find the right cap/resistor combination.
On my breadboard I had it like this:
To pedaboard, Cap leg with resistor to ground, Cap leg to DC power, DC power, DC power to Cap leg, Cap leg w/ resistor to ground, to guitar;
and of course common ground between the AC signal and DC power. I tried with smaller caps, but it would just cut out sound, and larger caps in parallel let more sound through, but as soon as DC was applied there was no sound at all, minus an oscillating whine.
I have been considering other cables. sigh I have so many mono 1/4 cables as backup, I'd hate to have to switch to another type.
As for a midi cable, that is a good idea; but the music I play, we tend to not have any use for midi..(YET! until I build a midi tracker for my guitar, but thats another story).
I have considered using a Stereo 1/4 cable. On the tip would be the guitar's signal, ring would have the ground, and the shield would have power.
I would swap the ground and power only if it wouldn't make it sound horrible. And all I would need is a short sensing circuit on my pedalboard, basically measuring the resistance between the DC and ground. The arduino would do a test on startup and make sure the resistance is >100 ohms, then enable the DC power. So it could sense a mono cable plugged in instead, and automatically disable the power.
But then I'd have to buy some Stereo cables, and they may be less common on stage.
Far-seeker:
The math for this is fairly simple,
This is the math:
|
V _________
---/ d(0.0)b --->
^
Right over my head.. ha
How would I know which frequency to drown out for the AC? I may be wrong, but I though DC was a low frequency.
Far-seeker:
? = R * C
? = 5*10-5 s (I got this by inverting 20 kHz, your target value could be different)
R = 8000 ? (lowest possible load is the worst case)
Solve for CC = 5*10-5 s / 8000 ? = 6.25 nF
How did you invert 20khz into 5*10^-5 ?
And to what scale would I use the resistor to ground the cap?
Since it would be a cutoff for (above?) 20khz, would that alter all sound above it? (fm frequencies for communication between arduinos)
Thanks for your patience, I appreciate it!