rebote delay @#$%ing weird de-bugger..

[deadastronaut]

ok guys, ive built a rebote, same as before, but i'm getting this weird input problem..

ive audio probed it, from the input cap,82n (100n) into a 510k (560k) , but im only getting probed sound on the right side of the 510k, nothing before it.

ive re-flowed/ soldered those connections before it but no audio is getting through....very strange..any ideas, blown cap?..dodgy resistor?..

i know the circuit is working as a delay because i can get it to work fine when putting the probe on the 'happy face point' on this diagram...

a penny for your thoughts...

[charmonder]

Just brainstorming but could it be the 1m resistor? I saw someone else's thread where the guy realized what should have been brown black green was actually green black brown,(  which would send the input signal right to ground )

[deadastronaut]

AHHH correct, i had a brown green black 15r....i shall slap myself vigorously ,  as a piss poor excuse, it was 3:30am when i populated it...
cheers man!!!!!...that'll teach me for soldering when tired!!!!!...


edit: sorted now!!!... thanks man!.


as side notes for anyone else building this:

swap 33k for a 22k..this will give louder repeats.

swap time pot for 100k , but stick a 150k resistor on outer lugs..(this will make it 60k) .this will give you a tad more delay time before it goes into dirty....(thanks phil )

put a 100k trim on the output to get unity. have fun.

[charmonder]

Well I'm glad that helped!


It's kinda funny, that you mention that technique for getting a 60k pot, it never occurred to me...  But that's the right-under-my-nose solution. See I've got all the resistors and caps to last me a few years, but it's too expensive to stock up on every pot value I might need...   I haven't done the math yet but I hope I can just use 3 or 4 primary pot values, and add some parallel resistors to get whatever I actually need.  I guess this is also a neat way to get custom dual gang pots should you need that

[deadastronaut]

yeah its very handy to know....i'm crap at maths though!..

but its good to put a pot on a breadboard and use my resistor substitution box to experiment with values....

[Seljer]

Because of the setup of the opamp there should actually be no audio on the right side of that resistor!
The inverting amplifer has the positive input tied to the fixed bias voltage, the opamp with its feedback topology adjust the output so the negative input is also at the same fixed voltage.

[deadastronaut]

@simon,  ive got it working fine now...i had wrong input/ground resistor...