Mikrophone with no piezo - working breadboard

Confirmed build - really useful for getting you guitar/mic/cd player up to Eurorack level.

Will solder up and post stripboard layout tomorrow.

Ps if you want to add a piezo disc panel

thats easy… I’ll post pics when the piezo discs arrive in the post!


Epic announcement! Bravo. Pushed this to top of my list. Many thanks


Mikrokosmos has an input jack so can be used with an instrument too, if you want to go the PCB route and have a cool front panel with piezo scratch area. But definitely it’s a simple enough circuit for stripboard and a homemade panel too. Unfortunately the new run just sold out but Gerbers and schematics are in the repo.


I highly recommend the mikrokosmos. It’s starting to be one of my most used modules, which surprised the heck out of me.


So now you’re just “seven”? :rofl:



I still have a couple of PCB/PANEL in the UK…



Yeah, the Mikrokosmos looks great - I just watched the demo video

Kosmo format is just too big for me and as it’s a very basic circuit stripboard suits me for this build.

I got a piece of blank pcb to try out etching a panel and its, well, distressed.

I would have added the piezo but I bought an electret mic by mistake. I’ve got one LM78L05 that could feed it the required 5v power it but I want to use that in another project.

And, what I like most about the mikrophone module is the (high impedance?) input jack.

I’ve settled for ebaying a pack of piezo discs and I may even solder one to the switch of the input socket when they arrive :joy:

Will post a stripboard layout when its done.


The input connects to the cathode of a diode to ground, a resistor to ground, and the input of a non inverting amplifier. The former and the latter are very high impedance for positive voltages — essentially no current flows there — so the input impedance is just the value of the resistor, which is labeled “1m” but presumably is really 1M (megohm, rather than milliohm). So yes, high impedance.


I believe I have a spare Mikrokosmos or 2 (in the US) - shoot me a message :slight_smile:


Thanks for the explanation - and the
Clarity on M vs m

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That led me to write a blog post about SI prefixes: https://mathematrec.wordpress.com/2020/09/10/metrics-furlong/


Bookmarked! Great reference

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Imperial has furlongs, and it has teaspoons, tablespoons, ounces, cups

Nit: Teaspoons and tablespoons are widely used in metric countries (5 ml and 15 ml). Cups exist too, but nobody agrees on the exact size (*), and many countries just stick to l/dl/spoons or grams in recipes.

*) Internet may tell you that the “metric cup” is defined as 250 ml but that’s only true if you’re in Australia.



What happens when you try to convert a US imperial to metric and then onto UK imperial?

Apparently this kind of stuff really messes with US recipies when you make 'em In the UK. Or are egs diffrrent from ohms?

I know a dude who got a gig updating old Marthon’s to Snicker’s size. Apparently it’s not that easy.

Then they got a job servicing returned polo mint holes. But after a week or so they got bored with tha tand started working at Maplin’s.

Sorry, it’s a bit late here in Australia.


interested too on a pcb please , if you have a spare one .