Messages

Is it just me, or is the input cap on the hipster schematic backwards? Shouldn't the positive side go towards the signal? Is there a reason for this?

I tried googling silicon fuzz face and found many versions of the schematic with the cap either way! Seems like its rather random.

Well the tl072 is indeed fake. I found one that came in a kit and BAM works great. It even works better then with the TL082 so thats an even greater thing.

So, now we know, the Afterlife is good for testing fake chips!

Have you tried using a diffused red led instead of water clear?

Well the LED is only there for testing, to show that the opamp isn't doing its job. I am using the recommended vactrol for the effect.

The other one between the two pots. The effect uses an LED and a Vactrol for compression. I was having probably let the same issue you were, I bet I read the BOM about 10 times before I realized what it was saying.

Maybe MadBean himself will chime in on this, but according to the schematic, the indicator led is in no way connected to the circuit.

I've ordered some tl072's from Tayda (usually a good supplier) and I'll look through previous projects to see if I can find one that might have come from mouser or digikey.

I will also take all the measurements again now that its out of the box, and check out the vactrol resistance, although I seem to remember it being ~2m.

Have you tried using a diffused red led instead of water clear?

Well the LED is only there for testing, to show that the opamp isn't doing its job. I am using the recommended vactrol for the effect.

Here are some pictures. The last picture is with the TL082 and the led is off. If I strum the guitar the signal effect the brightness (as expected) and the effect works.

I would use the voltage divider like in your schematic. A TL2426 works good if you need +/- each half of the supply (9v = +4.5, G, -4.5)

You could also use an adjustable regulator (LM317) and calculate the correct resistors (use a trimmer) to get a perfect 4.5v.

I didn't test with an audio probe because I don't lose audio anywhere. With a signal or not present (guitar not even plugged in, or volume down) the LED in (parallel with) the vactrol is always on.

I will un box it and take some pictures. As I figured this effect was working I have boxed it up, it was only after watching videos that i realized something was wrong.

I have already re flowed all the solder joints, but the cold joint was also a possible culprit in my mind. Still doesn't explain why it works with a TL082 though.

So I built an afterlife a few weeks ago, with all the stock values, no subs. I thought it was working, but seemed very minimal so I looked at some video demos, which made it seem a lot more apparent. I checked it my Vactrol is correct, and it is, so I took a standard LED and bent the leads out so they would contact the LED leads on the vactrol, and the led lights up. No guitar signal present, nothing. the brightness doesn't change with guitar signal, so obviously the effect is not working. I tried numerous other TL072s with the same result. These are all from the same seller and I've used them in many projects (eurorack synth and stompbox) without previous issues.

So I tried a tl082 from my parts bin, and low and behold the LED is off, until a signal is present, and it seems to react as expected. The effect is a bit noisier as well, but sure works as I have expected.

This made me think maybe my supply of DIP TL072's is at fault, so I made an adapter for a SOIC tl072, and it has the exact same response as the DIP ones.

So what could possibly be at fault here? Why would these chips work in so many other projects but not the afterlife? What can I test to give some better ideas? I've checked voltages, and don't see anything obvious.

TL082:
4.41v   -|1   8|- 8.76v
4.40v   -|2   7|- 4.40v
2.22v   -|3   6|- 4.40v
0.01v   -|4   5|- 4.40v

TL072
5.39v   -|1   8|- 8.79v
4.60v   -|2   7|- 4.20v
0.79v   -|3   6|- 4.43v
0.01v   -|4   5|- 4.43v

All measured with respect to the ground on the DC jack

I know this topic is a few days old, but I'm following the same route. First I built the Aquaboy stock, then 15v version, then modulation, and soon I'll be doing the dual MN3005.

My question is, after adding the modulation, I notice a lot of clock noise when the effect is bypassed but the modulation switch is still in the on position. What about you? Do you notice clock noise in this scenario? I have tried moving wires around and it doesn't seem to get any better. I've already had to use a wire direct from the stomp switch to the output jack because the pads on the board were giving me clock noise even in the stock configuration.