Good job with amplifier, by the way - reference design layout section shows bypass capacitors from supply rail to ground, 2 of them. (C1 and C4 on page 15). Though their ground plane usage raises some questions from me... These aren't shown in schematics for some reason, but appear in layout - it may not cause significant issues here, but with faster opamp, different supply, etc. this can cause issues, most likely oscillation.
Oh, found one more reason for C1 (in reference) in particular - looking closely this circuit instead of rejecting power supply ripple/noise amplifies it! microphone is current source with high impedance, reference voltage is lowpass-filtered, so for power rail AC content this circuit functions like inverting amplifier with gain of - Rfb/Rbias...
In all honesty, I wasn't planning on selling the boards as creating them through LCLPCB would be less expensive and you can modify or change the layout to your liking. Thanks for asking though and good luck.
Your channel deserves more subscriber … love your work
That’s very kind to say. Thank you. I have fun putting the projects together. I hope it inspires you to create too.
Nicely done. Just for clarification: the AKG C535EB is also an electret microphone, but a really good one, with an output transformer.
Nice project. Maybe add a simple, passive, bandpass filter to remove all frequencies that are not within the vocal range?
Absolutely. The add-on options are almost endless. If you try it, I’d be very interested in your results.
Good job with amplifier, by the way - reference design layout section shows bypass capacitors from supply rail to ground, 2 of them. (C1 and C4 on page 15). Though their ground plane usage raises some questions from me...
These aren't shown in schematics for some reason, but appear in layout - it may not cause significant issues here, but with faster opamp, different supply, etc. this can cause issues, most likely oscillation.
Oh, found one more reason for C1 (in reference) in particular - looking closely this circuit instead of rejecting power supply ripple/noise amplifies it!
microphone is current source with high impedance, reference voltage is lowpass-filtered, so for power rail AC content this circuit functions like inverting amplifier with gain of - Rfb/Rbias...
I’m glad I didn’t put the bypass caps in. Thanks for your great observation. It’s very helpful.
Awesome 😎
Thank you.
Is your board for sale?
In all honesty, I wasn't planning on selling the boards as creating them through LCLPCB would be less expensive and you can modify or change the layout to your liking. Thanks for asking though and good luck.