Rebote 2.5 question

[coxter]

Hi, I was looking at the tonepad schematic of the delay when I spotted the part with pin 1 and 2 x 47uf caps and a 0.1uf cap.

What is the point of that? Can I just substitute with one 100uf instead?

Now my pedal doesn't work, not sure if that is the reason because I substituted that whole section with one 100uf cap.

Last question, am I suppose to combine the digital ground with the analog ground?

[bluebunny]

I don't see why you shouldn't sub the 2x47uF caps with a single 100uF.  It may have been for reasons of size?  Someone help me here, but I think the 100nF might be to reject higher frequency ripple (but not sure how much of that you're gonna get coming out of the regulator?).  Either way, I don't see how the sub would have made the whole thing not work.  Time to start debugging...   

The tonepad layout connects pins 3 and 4 - analog ground to digital ground.  I've seen other 2399 circuits leave pin 4 unconnected: it's connected internally (by a low resistance) to pin 3.

[coxter]

Well it kinda works
The top half with the buffer works like a dream.

Somehow I only get a very soft single repeat with all my settings on full.
I now wonder if I damaged the chip... No socket... Sigh..
I used a 7805 instead of a 78L05, don't really think thats a problem
Got a healthy 5v out of it


Anyway I played with the 24k resistor at pin 14 to get more gain.
Increased it to 100k and then to 500k and then to 1meg, lol!
It kinda works! Repeats is slightly louder but still dismall.

[bluebunny]

Hmmm... not had a problem getting a decent level out of mine (built on the tonepad board, btw).  Not sure if a fried 2399 does much of anything after it's died...  Perhaps time to hunt around for cold joints, incorrect res/cap values, etc?

BTW, found some original (pre-tonepad) schematics for the Rebote.  They do indeed show a single 100uF cap, not 2x47uF.  The 100nF is still there though.