Peter Blasser made a similar amp based on that there schem lol
Mind you it is really meant for the crazy oscillators he designs lol
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LM386 amp circuits are all over the place. I built my first one almost 30 years ago in high school - and friend and I learned the magic of resistor ladder DAC’s and built some really primitive 8bit discrete DAC’s to hang off the parallel ports of our computers since we couldn’t afford soundcards…but a few games (I remember the original 1990 Links and other games from the same developer - Access) and most notable to us modtracker supported parallel port DAC’s for sound.
We were so happy with them we ordered a bunch of parts from Digikey and started building them up to sell to friends. A plan which fell apart when we took them to school to demo and realized that our
new 386 computers had plenty of power to play a game and shove bits out a parallel port for audio…but the 286’s and 8088’s most of our peers and our school had were…not nearly as capable 
When we first loaded our demo on one of the school’s newest 286’s we though it was just going to be slow to load and start working. Then it started playing…and quarter notes were taking 2-3 seconds each 
I still have some of the resistors and housings we had bought in one of my parts bins.
There was even a commercial version: https://en.wikipedia.org/wiki/Covox_Speech_Thing We had just paired ours with a small LM386 amp so they could be plugged directly to headphones or speakers.
More on-topic. A few years ago when I first got into building cigar box guitars I needed an amp. So I dug up one of those old LM386’s still kicking it in my parts bin and wired up a simple amp circuit:
Once I confirmed it worked I just soldered it up free form and shoved it into an abandoned surround sound speaker some previous tenant of my house had left behind before I moved in:
Still have it and still use it…but since the battery just kind of dangles in there and isn’t mounted to anything it tends to tear itself apart if I’m not gentle with it One of these days I should clean it up and add an external power jack. Could be fun to integrate one with the megadrone board in it’s own standalone package…
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Excited for you! Have fun 
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did it arrive without tracking ?
Yes, without tracking.
1,10 and 22 thats sounds great and you went with yellow leds?
how long to get there, they lost my first fart box, so I get anxious at getting their stuff here in USA
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Orange concave, actually, so they sit flat with the panel.
Took a little more than three weeks.
I haven’t got mine yet either if it makes you feel better 
yes it does , how many did you buy (fart Box)?
I’ve just finished building a decadrone and it sounds really cool! But the master tune and cv don’t work. I bought these MOSFETS as described in the BOM https://www.ebay.com/itm/5-PCS-STP16NF06L-STP16NE06-STP16NF06-TO-220/153019588764 and installed them using sockets. Can anyone help me out?
Cheers,
Sjaak
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I’d bet a modest sum of money, if that was a thing I did, that you have a bad joint or two somewhere. There’s not really a lot else that can go wrong with this build. Are the individual oscillators all producing sound?
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All the oscillators are making sound and I didn’t find any bad joints yet. I will reflow everything tomorrow just to be sure. However, I didn’t adjust the trim pot at all. How did you calibrate yours?
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Oh, that’s probably it, then. It’s kind of an offset and it has to be low enough for the master tuning to take effect and I guess the CV too.
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yay got my shipping notification this mornin lol.
(ordered at the same time as the vinyl - so they held the megadrone til the vinyl came out today)
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MOSFETs have a rather narrow window where they work as resistors, and the exact threshold voltages vary between transistors (The Vgs(th) for STP16NF06L is specified as 1−2.5 V).
Sam’s design assumes it’s at least similar for all MOSFETs on the same board (e.g. that they’re from the same batch), but you will need to tweak the RV24 trimmer to make sure the internal CV is in range. Easiest is to try a few trimmer positions, tweaking the master tune at each position, until you find a setting where the master tune has the most impact.
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I was able to get it working! The knob’s range is quite small however, not even half a turn. Do I need to keep tweaking RV24 or could I try a different value pot or something?
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I recon keep on tweaking RV24, however it is a very lofi solution. however I have been getting batches and batches of the 16nf06’s and with the added trimpot if does seem quite good some mosfets have a thinner curve and some have a bigger. but definitely keep fine tuning and maybe if your near the extremes of the rv24 twists, maybe the 100k next to it could go up or down in value but its tough to say which way at this point!
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Me too… Can’t wait.
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