Questions about the Lofi Delay by Renegadrian

[duck_arse]

insert a resistance of say 1k in between the IC pin 6 and the delay time pot "pin 3". this will then stop the pot from going to 0R, will stop the IC locking up at startup from being too low a resistance on that pin.

100R, far from being too low to do anything, when connected to the "AUDIO OUT" point will pull ALL your signal to ground. all. use 100k or so, it's only there for pulldown, as ever.

the 10k/10uF/1k string to the output - it looks to be missing something, like a cap to ground as a filter, say, but we dunno what or where or if, cause there's no circuit diagram. also, two resistors in series is pointless, you might as well delete the 1k following the 10uF. unless good reason appears with the schematic.

[moid]

Another picture, hopefully this one is better?



The stop resistor makes sense (I'd forgotten that the PT2399 needs some resistance when it powers up or it locks up. Great feature that one!)

I always get confused with resistors to ground (OK I always get confused with anything electronic, so nothing new there I guess), it always seems to work backwards to me... so it should be that less resistance means the signal is more likely to go to ground because presumably we are offering the electricity an easier path to ground than the path to the audio out - so we need to add a higher value resistor so that the path to ground is less interesting to the electricity... which of course in my brain begs the question, why have a resistor to ground at all then? Presumably it corrects something else - is it to do with keeping the impedance value correct for the next pedal? Or something else?

I've removed that 1K resistor that was in the string of 10k/10uF/1k becasue as you say it does seem rather pointless.

[moid]

Hello chaps
In the interests of scientific progress, or I was waiting for layers of paint to dry on some enclosures, so I thought why not, I breadboarded the above circuit. Assuming I did that properly (me and breadboard don't have the best of friendships) the circuit does not pass any guitar sounds or my phone plugged into it either. It is does however make a pretty good steam engine synth though! It sounds like a train going at speed up a steep incline, puffing like crazy. The time knob allows for puffs of steam to be nearer or further apart and the repeats knob may or may not do anything. I used my audio probe on it and the guitar audio is clear at pin16 of the IC, is also audible at pin 15 but is mixed 50/50 with steam train sounds and from pin14 onwards only steam trains can be heard. So maybe this circuit needs some other connections or components that were not visible in the image I traced it from to work. Might not be worth going any further with this, unless you do need a steam engine sound!

[duck_arse]

you must be chuffed about that.

[moid]

Well at first I did get rather steamed up about it, but then I realised I didn't want to be railroaded by a circuit.