Chorus is created by passing the signal through a very short delay line, somewhere between about 8ms and 25ms. The delay time is modulated and the delayed signal is mixed back with the original un-delayed signal. Some feedback ('repeats') is often applied too, to thicken the effect. The PT2399 has a minimum delay time of about 25ms, which is just short enough to do a thick chorus effect. The more subtle chorus effects that a 'proper' chorus pedal would do are not available as they require shorter delay times ( but I'm one of those people who only ever wants his chorus thick!). However, as well as getting chorus I soon found that various other unexpected effects could also be had for free, including pitch bend and a kind of ring modulation. That's why I've called it 'weird chorus'.
It will fit in a 125B with top mounted jacks easily, but it's narrow enough that it will fit in a 1590B, but probably without the pots board mounted. Here's the original build doc with the schematic and Merlin's original layout.
what can i sub the bc337 with?
ReplyDeleteThey are a whopping .05 cents on Tayda. Why bother substituting?
Deletehttps://alltransistors.com/crsearch.php?mat=Si&struct=pnp&pc=0.36&ucb=50V&uce=45V&ueb=5V&ic=0.8&tj=150
ReplyDeleteYO HE VARIADO POR UN BC548 Y UN 2N4401,,FUNCIONA MUY BIEN,,TAMBIEN 202 EN VEZ DE 222
DeleteHello, I like this one, it reminds me of the Danelectro FAB Chorus but with no mix pot, I would like to have a more useful sweep range for depth pot, should I try bigger or smaller values?
ReplyDeleteHi! Maybe I'm wrong but I think there is a little mistake with this layout.Resistor 47k and diode 4148 must be connected to +5v ,not to ground.Resistor in series with rate pot is 4,7k not 47k.
ReplyDeleteCan confirm these fixes make the pedal work "as it should."
DeleteHaha this is a weird one and I love it, and I'm pretty sure it doesn't do anything that "it should."
Made the fixes to the board.
DeleteDobrin, it work for you with that corrections? Mine not yet.
ReplyDeleteIt works. Verified
ReplyDeleteAwesome. Thanks for verifying!
DeleteVerificado, tal como esta, recomiendo usar zocalos en transistores y capacitores para variar, experimentar con otros valores.
ReplyDeleteVERIFICADO
ReplyDeleteMuito bom! Usei BC549 em lugar dos BC337, a princípio está funcionando muito bem! Saudações do Brasil.
ReplyDeletePlease tell me where to connect 2 dots mix wet from where to where? Still confused.. Someone please telling me
ReplyDeleteThere is 3 pins of of the toggle switch,, pin 1 for mix wet1, pin 3 mix wet 2 then where to connect the second pin of switch??
ReplyDeleteThis is a very cool chorus. I enjoy how it can basically go from nice lush sounding chorus to weird pitch bendy noise machine at a twist of the depth knob. Speaking of which, the depth seems to be shown here in reverse.
ReplyDeleteThe only other thing I noticed (and it's probably just how the circuit works) is that the ramps up and down in pitch are a bit abrupt, rather than a smooth sine or triangle wave. It's really only noticeable at max depth though. Otherwise, great sounding circuit, and sweet layout!