Instructables

Step 2: The Schematic

My schematic is largely (read: almost entirely) based upon Casper Electronics' EchoBender pedal, which is in turn largely based on Tonepad's Rebote 2.5 Delay pedal, which is in turn, more or less, based upon the example schematic in the PT2399 datasheet. Having breadboard all three, I personally can not hear a significant difference in sound between the Casper Electronic version and the one on Tonepad, which some people say is superior sounding (the one in the datasheet just sounds flat). The nice thing about the Casper Electronics version is the inclusion of a feedback pot, which gives a really full sound to the echo effect.

The things that I have changed are a few mildly significant resistor and capacitor values. The biggest difference is that I have removed the "long delay" distortion pot. This potentiometer is basically forcing the chip to under-sample the input to create a longer delay and, in my opinion, doesn't sound very good. If you like under-sampled, long-delayed, audio, by all means throw in a large (1M) potentiometer in series with the delay pot. As you may have also inferred from this, the longer the delay, the less clear the output signal; so be warned that even the "short delay" starts to degrade when cranked up all the way.

For redundancy sake, I have redrawn the schematic. I have put three image notes on my schematic to indicate parts of the circuit that have changed. The schematic drawn by Casper Electronics is much more clear and I recommend you mainly go by that one.
 
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danricramz2 years ago
only my comment for this project is only the capacitor uf. has indicated. but the voltage does not. so it can be over voltage the IC and it won"t work properly.. please reply me as soon as possible thanks.....
Gizah2 years ago
What's the cap symbol with no indicated value after the 510k resistor? And where do you use that SPST you mention in the parts list?
randofo (author)  Gizah2 years ago
5 - 10pF. You can probably even leave it out.

The SPST switch I was using as a power switch. You can probably use stereo jacks instead of mono such that when you plug in a mono guitar cable have the extra stereo connector complete the circuit by making the ground connection.
nikolozj3 years ago
oh! I thought "better diagram" meant the one you drew but with better quality. I just wanted to have a better picture of your own diagram, even tho you said that it's almost entirely based on casper one, I still wanted to look into it with its all details. I can't recognize some parts of your version of diagram because of low quality of file, even if I save it on disk and then zoom it, then the quality gets worse and I can't see clearly for example cap marks or any other detail... I'm a beginner amateur electrician so I need to study diagram carefully to get it. please let me have your version of diagram with better quality and sorry for causing so much trouble!
randofo (author)  nikolozj3 years ago
nikolozj3 years ago
could you please update "better diagram" link? thanks!
rravenn4 years ago
hey do you have a better diagram?