Wednesday, August 30, 2017
Colorsound Tremolo
Haven't done a tremolo in a while, so let's remedy that with the original 4-transistor Colorsound Tremolo (the re-issue is the 3-transistor version). Originals used 2SC945 transistors (BCE pinout), but I've laid this out for more common NPN transistors with CBE pinout. You might want to use a C100k pot for the Speed control. Here's the schematic for reference.
I've done it on PCB and it works ! You can tag it verified...
ReplyDeleteBut when I add the LED it doesn't pulse (only a dimmed light) and there's no more effect. Any idea on how to add this nice feature ?
Another question : the speed pot could have a wider range, from very slow to ultra-speedy. How can I achieve that ?
I forgot to mention that the depth pot is effective only on the first 1/4 of rotation.
ReplyDeleteTry increasing the value of the speed pot and lower the value depth pot. Not sure about the LED. Maybe check the Tagboard blog post with this same circuit.
DeleteAlso thanks for verifying!
DeleteYou can increase the value of the 220nF cap to 1000nF, and dont ground the pin on the depth pot. Connect it to pin 2 instead.
Deleteyou will get a small bit of noise from that adjustment, but it can be filtered with around a 47nF cap between output and ground
DeleteWhat pin do you mean? can be more specific?
DeleteThanks for the tips. And for the layout of course !
ReplyDeleteStumbled across some info on the LED. Just connect the + side of the LED to the collectors of Q2-3. The connect - side to the footswitch as you would normally. I'll update the layout with a pad for doing that shortly.
DeleteWhen I did this I noticed a change and drop in the tremolo effect and when the speed is maxed the effect goes away, any thoughts?
Deleteverified!! really nice, but I have the same problem with the LED as eve-the-frog!
ReplyDeleteexcellent website thanks for the projects
I've built this on pcb and on vero - all I get is clean output, no tremolo effect. The LED pulses just fine. I'm confused.
ReplyDeleteFor anyone wondering about the LED (I got everything working and took some time to experiment). You have to add a resistance between the LED and ground. I got these results with a C100k speed pot:
ReplyDelete* Little to no resistance (~<1k) will ground the pulsating signal resulting in no effect.
* Low resistance (3.3-5.7k) will result in a dead zone on the speed control.
* Too much (>10k) and the led will be too dim.
I got it working with ~7.6k (33k and 10k on parallel). But still, the Super Bright LED I put gets as dim as a regular one. So I'll modify it sometime. Maybe some transistor would be a better choice for powering the LED.
Update: I added another 2N5088 for the led to work. Base to the LED+ on the board, Emitter to the Anode of the LED and Collector to +9v. Works great. Also changed the 100k depth pot for a B25K for a way better working range.
Deleteneed to add some resistance between the emitter and the ground?
DeleteI can verify this, thank you!! Worked like a charm! And yes add a resistor between the cathode of the LED and the footswitch lug, I used a 7k4 it was close to the mentioned 7k6 and works great!
DeleteI added bc547 instead of 2n5088 but didnt work if led works theres no effect
DeleteI add a 6k8 resistance in the base of transistor and a 1k resistance for the LED. Work well.
DeleteWorks
DeleteI could use a Darlington (MPSA13/TIP120) for Q2+Q3 right?
ReplyDeleteYou could try it, but the typical HFE of an MPSA13 is 5000, while the combined HFE of 2, 2N5088s would be 160,000.
DeleteHello everyone!!. I'm from Brazil and maybe my English is not very good.
ReplyDeleteWell, I built this tremolo but all I got was a clean sound at the end, with no effect whatsoever. All values and operation of components checked several times and pcb without possible short. Any bright ideas for me? Thank you.
Hi, can you make original circuit for ECB japanese transistors, I have few 2SC945, and also I don't have any EBC transistors anymore..or just tell me can I make this with C945 but only if I connect transistors lugs properly, base to base, em. to em., col. to col.?
ReplyDeleteYeah, you can just twist the transistor legs around to fit in the right holes. Just be careful not to short any of the legs together.
Deleteolá ! Sou do Brasil, esse circuito realmente funciona ?
ReplyDeleteHi! I'm from Brazil, does this circuit really work?
ReplyDeleteGood afternoon, I set up the circuit but only the sound comes out clean, without modulations.
ReplyDeleteQuit the LED. It works
DeleteWould 2n5457 or 2n3904 or or 2n3905 or 2n3906 work???
ReplyDeleteAnyone reply?
Delete2N5457 is a JFET, so no. 2N3904 will probably work
DeleteTy ill try
DeleteIt worked but speed is fast its not slow on video. I did use 500klin though..
ReplyDeleteAny suggestion? It is working but its not playing slow as in video
where can i get a schematic for this?
ReplyDelete