Waiting for parts to arrive, figured I’d give a take at building a 4xSSO drone module in the meantime.
I’d like to use eurorack power though, and I know that some people were having trouble with that.
@analogoutput - I know you’ve (somewhere) previously written about running this off of +12/-12 rather than +12/GND - if I give that a shot, are there any other caveats you think I should be aware of (changing resistance/capacitance values)?
Cheers!
Again, I’d say breadboard it. I vaguely recall I tried it and it worked, but what effect there was on frequency range I don’t remember.
(I just used the schematic
and connected +12 V at the top and -12 V instead of ground at the bottom. Of course the audio output jack should connect to Audio Out and ground, not -12 V.)
4 posts were split to a new topic: Need help with headphone connector pinout
So what to do if the LED blinks once and only once with a 2N3904 on 12V supply?
Hello and welcome to the forum, if the led has only shone once, it may be that it has burned out, check your circuit again, surely there is a problem somewhere
BTW the 2N3904 need more than 12V to oscillate i think
Welcome! Just once, is that each time you power up or only once ever.
If it’s just once each power up then check the capacitor value and all the connections. Also make sure you’ve removed the middle leg of the transistor.
If just once ever then the led may have died.
If you search the forum there is a large discussion on the SSO and making it work. Keep us posted.
Each time I power up. If I discharge the capacitor and plug it back in, I get one pulse again.
I triple-checked the circuit wiring, I’m confident that isn’t the issue. Next I’m going to try increasing the supply voltage.
I’m not sure if it has been posted already but here’s a nice link about avalanche oscillators.
http://www.kerrywong.com/2014/03/19/bjt-in-reverse-avalanche-mode/
Is says the 2n3904 needs 12v to oscillate. However with the resistor from emitter to b+ it will get a little bit lower voltage.
Assuming that wiring is correct it might be worth either increasing power supply voltage or swapping the transistor. You can try the same transistor or another type. Some might oscillate at a lower voltage than others, even if they are the same type.
I’ve had some vintage transistors oscillate well below 10volts
Increasing the supply is a good call now or take a look at Kerry’s list for a transistor that will work at a lower voltage. Keep us posted.
With 2N3904 mine work with 18V, and an SS9018 begin to oscillate at 8V, so good for 12V.
Hi guys! Loving this group and everything Sam is putting up online! Surprisingly I’m having some slight issues with the SSO 
So far I’ve just built it on a breadboard, and it worked first time to some extent. The range of the oscillator though is very small, and regardless of what capacitor I use it won’t oscillate above a certain frequency/pitch.
I’m using SS9018 transistors with 12v power and using all other components as per the guide.
I tried using a 100k pot because I had it to hand - this extended the range of a 10uf cap DOWN a lot, but it still wouldn’t go above the pitch at which it seems to die.
The pot changes oscillator freq for about 2/3rds of it’s range, but then the oscillator sounds like it gets starved and conks out.
Any thoughts would be AMAZING! thanks, Joe.
Does it just stop going any higher, or does it stop oscillating altogether when you try to turn it higher?
It stops oscillating but the LED stays lit.
I’m getting 12v on the breadboard, but only around 4v at the transistor emitter. Appreciate there wouldn’t be 12v after the 1k resistor and potentiometer, but not really sure what readings I should be expecting.
That seems to be just the way the circuit works, when the resistance is small enough oscillation stops. I found that happening when the pot resistance (measured out of circuit) reached about 1k (total resistance to the 12 V rail about 2k), so even with a 10k pot I got oscillation on nearly all the pot range, but it did cut off right before the end. With a 100 µF cap it was the same, cutting off at a much lower frequency but about the same resistance. I would not be surprised if the minimum resistance varied from one 2N9018 to another but I didn’t try that.
If it offends you that you can’t use the full pot range you could increase the 1k resistor to above whatever the minimum you observe is, it wouldn’t get you higher frequencies but it’d oscillate over the whole pot range.
Thanks for the tips! Think I might just go for a 40106 instead…!
Hi everyone! Some time has passed since you all discussed this but I hope you can help 
I have done the circuit as shown in the video and supplying with the 12V turns on the LED, so I think it is done correctly.
But i can’t get the audio right…When i “connect it” to the speaker, I can only hear noise like when you touch the aux cable with your fingers with the speakers on.
I wrote “connect” because I can’t quite understand how to do it, so I haven’t soldered anything yet, and I’m just touching the cables I think I need to.
So what I need to ask is how to “plug” it correctly so I can hear it. Why is there only 1 “OUT”? Shouldn’t I need a ground too? I bought a TS (female) audio jack to which I connect a cable directly to the speakers. How do I use it?
Btw I tried “connecting” the OUT (loose red cable) and a GND (loose white cable) to the Tip and Sleeve pins, and the LED shuts or I hear noise like i mentioned
HI! I have been through some trouble with this and made this post : Getting the SUPER SIMPLE OSCILLATOR to oscillate - #56 by mtrovao
And after seeing this troubleshooting from you I tried connecting it directly to the positive leg of the LED, and the only difference i notice is the noise im getting is louder as expected. Any ideia?
Hello. It looks like you need a better connection to your power source for sure. You should cut that adapter from the wires (make sure it’s unplugged from the wall first) then determine which wire is positive voltage and which is ground and twist the leads from you circuit board to the appropriate power wires. From what I can see it looks like the rest of your circuit is layed out ok but I can’t really tell from your pic. It would help to have pics from a few angles of the top and a pic of the other side of the board too. Also it would help to know what transistor you chose. If you are using the 2n3904 then it looks like you’ve got it backwards. Get the power connection sorted out for sure though. You definitely don’t have a good connection there. Welcome to the forum. You should be able to get this thing to make some tones.
Hi! Thanks for the response! So, as i can’t cut the adapter and use the cables, since it is the power cable to my electric piano, I went with the two 9V batteries choice. I noticed a couple of things!
Pros:
-the LED is much brighter now, and it is more stable, as you can see in comparison to the photo on my last post
-there is no noise like the one I mentioned previously too!
Cons:
-It still doesnt work xd (connected it to both my guitar amp and desk speakers)
I hope the new pictures are of help! About the transistor, yes it is the 2n3904 like the one in the video, and I think it is correct from what I saw in the video (it is oriented like his), although I saw a few people talking about that orientation problem before. I saw someone saying that it is wrong in the electric diagram, but it is correct in the stripboard schematic, which is the one i followed.
I have:
Emitter to: R100K/ Positive Capacitor leg/Potentiometer;
Base cut off
Collector to: LED
Flip that transistor around. It is backwards. The emitter is on the left if the flat side is facing you. The emitter needs to be connected to the led. As it is you have the collector connected to the led. Give it a shot. At worst it still doesn’t work. At best it does…
