… Mistakes happen is normal. Thank you Sam, you are doing a great job that we all enjoy!
1 Like
Yeah, there were people working out triggering problems here and figuring out the pulldowns needed changing. Maybe everyone thought you were following the discussion so didn’t email you? Pretty dubious assumption but…
Given the extremely high input impedance of an Arduino input, there’s enough leakage currents in the circuit that things might just work for some % of builders… 
My sequencer was going absolutely nuts before I changed the pull downs. @lookmumnocomputer you should check out @analogoutputs code too. The different modes are awesome.
2 Likes
You mean flashy mode? 
I had some problems with skipped steps too.
If all I have to do is change some pull down values I might bring it back as a stand-alone. Even my 300mm cut down version is still more than half a shelf for me.
2 Likes
It would start going 1000 steps per second if I put my hand in a certain spot 
2 minute fix!
1 Like
Two minutes? Surely it would only take you a fraction of a second to remove your hand? I mean, if you have a very sensitive input circuit, don’t place a big antenna next to it 
2 Likes
Oh and also, the 78L05 is connected to the VIN pin, it’s better to either connect it to the 5V pin or use something like a 78L08.
1 Like
thanks dud. yeah as you can see from the schematic its a bit more involved than the stripboard layout. however that is mainly buffering and mixing circuits, but you can see the snare for instance is a bit different to the actual practical schematic which hopefully answers some questions about the stripboard that people thought were mistakes but they were not according to what I built to get the snare have more of a transient click on it.
Also! its worth adding, the 4011 works best being 4011AE. the buffered version (4011B doesn’t work so well) @fredrik has mentioned the 4011UBE (modern version of the AE but unbuffered) and I have ordered some to test to see if they work too and I will keep you updated.
if you wanted to keep it simple and just have all of the outputs summed together instead of worrying about seperate outputs you could skip 6 of the opamps. and just use the mix bus opamps. but it still does work without the opamps at all like in the stripboard layout, just I can imagine some instances it might not work so well. so just bare that in mind.
3 Likes
Just another question to be sure, on the stripboard layout, what’s the black line (GND) connected with nothing on the top left ?
The top strip is the ground supply rail in the original layout, so it’s just left behind from that version.
1 Like
aaah yeah never removed that. if you make it slightly longer you can use it as the hoop for wearing the layout as an earring I suppose 
4 Likes
or maybe use it to connect a wire for the external GND like the jack
3 Likes
btw i’ve just see that the snare is build with Noise and the Hi bongo in the stripboard version, and with the Low bongo in the new one 
Almost, but just a little bit of slightly almost OT …
I am looking thru a lot of Popular and Electronics from the 70’s and 80’s, searching for a 12VDC-to-115VAC converter and I just now, and saw this Drum Machine in RE 1980/5.
It looks sort of complicated or the designer just wanted to make sure it was super-ultra-mega-universal.
2 Likes
Nice, it has a piezo transducer and envelope follower so is meant to be used with a drum as a controller rather than just being triggered. The rest is a VCO/noise/VCF/VCA drum module, a very different approach than the twin T design. Lots of obscure (to me at least) and in some cases apparently out of production parts though.
It’s rather complicated, that’s true, but that’s typical of many of the designs from USA from that times. At least ICs are still more or less standard, but transistors …???
To point out and I think there’s a thread about this, unicorn-ICs can be found at unicorn-electronics.com in USA. A good and not expensive source of those hard-to-find components.
Also want to point out the World Radio History, a site where many of your favourite magazines and journals from the bronze age are skanned and offered free of charge.
However I do really miss a list of published projects.
Just a dumb question: what kind of capacitors do you recommend? Sam mentioned poly caps but I only have poly caps with the short legs (the boxed red/green ones, MKS/MKP etc.) and it’s a bit annoying to solder extra legs on them 
Or is it OK to go with ceramic ones?
I am mostly asking since I currently have troubles getting nice sounding percussion sounds due to noise, probably coming from my ceramic caps but I have not done much troubleshooting yet…
2 Likes