Require help on verifying Pitch Incinerator

[Esppse]

Hey,

I stumbled on this circuit and decided to give it a try. I noticed several problems with the layout and still haven't gotten it up, I was wondering if someone with more experience than me would like to have a go, it looks rather simple.

http://distorqueaudio.com/hardware/projects/pitch-incinerator.html

Things I believe are errors,

1. Missing 4 trace cuts under the 555 chip.
2. Pin 4 of TL071 needs to be grounded?
3. The input capacitor and the trace cut underneath it must be all on the bottom row.

- In the schematic it says 741 chip, but the very layout says Tl071, not sure if thats the problem

And I still have no sound after trying these out. Can anyone give me a hand in verifying this circuit?

Thanks

[PRR]

TL071 is a replacement for '741. Same pinout, mostly same-or-better performance. Not that "performance" matters here, but also '741 is becoming hard to find.

Yes on the '555 cuts and opamp negative power.

[Esppse]

Mmm, I'm still getting super super low input. I only get a small input signal even after slamming the input with a gain boost. The sound is low gain, then dies out, as if it's charge ran out.

[Slowpoke101]

Just had a quick look so this may not be very helpful.

Move the input lead up one hole to position 1g. It's currently in position 1h.
Good luck.

edit: Oh, IC1 (LM741) may like to have a ground connection too. Link pin 4 to the ground track just below it.

edit again: And you have already done all these changes...It would help if I actually read what you previously posted...Sorry 

[anotherjim]

It's got so much gain, I think a TL0xx type might latch up - I don't think they like losing feedback control which can happen if the outputs hit the supply rails in a sustained manner. A 741 would be better used like that, or another basic op-amp type. Alternatives to the 741 for that circuit would probably be dual types like MC1458 or RC4558 or even LM358 - you must wire the unused op-amp up or it can cause stability problems.

To continue with the TL071, try reducing the feedback R4 to 1M. And/or add a small capacitor across R4 to slow it down a bit. It will be pF value upwards from 10pF, maybe as much as 100pF depending on the R4 value you find best.

TL071 has a very high impedance input which makes it more sensitive to noisy environments which outside of a screened box certainly is. The basic but slow & clunky old 741 can be much happier in that kind of circuit.

With the 555 timer chip, the action of the DIS (discharge) pin causes a high peak current pulse which can cause trouble by making the power supply dip rapidly. That can be enough to keep resetting the 555. You need a good battery, and there really should be some capacitors across the 9v supply on board for when the battery gets weaker than new condition. An alternative 555 is the CMOS 7555 which doesn't pulse the supply current so much.

[Esppse]

Ah thanks for the suggestions. I did the resistor and cap change, it basically made it about 20% better. I still have to hit it super hard before the sound gets gated out.

I even added a cranked LPB boost before it, and it still needs more input gain.