Pork Barrel Noisy LFO - FIXED

[Scruffie]

I've screened the pots from the pcb using copper foil, with only the last cm unshielded, and the I/O wires from the pots and PCB, so I assumed that was sufficient. To braid them I would have to affix longer wires  to the pots but I can try it if you think its worth it. Unfortunately I decided to put the jack sockets at the top of the box, so everything is a bit open up there, and the I/O wires run the whole length of the enclosure under the PCB.

Regarding the cap on the MN3101 - I was just going to use a non-polarised ceramic but I might have a suitable size electrolytic around.

Never assume, shielding helps but it's better to have short wires in the first place.

No i'm saying DON'T braid them, I wasn't sure if you had or not 

Don't put the cap on the MN3101, put it across IC2.

[blearyeyes]

I have a Pork barrel without any extra shielding and it is quite. Most likely you have a cold solder joint somewhere or a solder hair, something shorting out or a bad component. Re-flowing solder joints is your friend. I have never braided pot wires and rarely see it done for anything other than cosmetic reasons. Did you find anything by tapping the components?

[wilsona]

Just want to be clear - I'm putting the cap between 4 and 8 on IC2, which is the op-amp.  Anything from 100nf to 100uf, if electrolytic then negative to pin 4, positive to pin 8. Right?

I will go round a re-flow it too, I did reflow everything around IC3 and 4, but I'll do the whole board.

Have not done a tap test yet.  Been a bit side-tracked, building a new telecaster.

Thanks.

[Scruffie]

Just want to be clear - I'm putting the cap between 4 and 8 on IC2, which is the op-amp.  Anything from 100nf to 100uf, if electrolytic then negative to pin 4, positive to pin 8. Right?

I will go round a re-flow it too, I did reflow everything around IC3 and 4, but I'll do the whole board.

Have not done a tap test yet.  Been a bit side-tracked, building a new telecaster.

Thanks.

Correct, i'd go for the higher end valued electrolytic, 47-100uF personally.

[wilsona]

I happened to have 20 (!) spare 47uF 25V electrolytics so used one of them - sorted! The pedal is nice and quiet, no hint of LFO in the background anymore. Now I'll just have to work out how to close the case....

Still got a slight problem with distortion - I'll open another thread for that if it bugs me enough (it probably will).

I can't thank you enough for all the help. I have learned so much from you all.

[blearyeyes]

Buy a Road Rage and run this @ 15v, more headroom and nicer sounding.
No more distortion...much better.

[RobA]

Excellent.

I'll give a big second for doing a 15V mod. It really helped mine out. I set mine up to run off an 18V input from my DC-Brick and then I regulated that to 15V using a little breakout board for the regulator circuit. I did sound better that way.

Now that I have an MN3207 in there, I had to run it back at 9V and there is some definite noise with it at that level.

If you've got the MN3007 in there, I think it's definitely worth powering it at 15V. Just make sure it's a solidly regulated 15V since you are pushing the limits of the BBD at that level.

[Scruffie]

If you've got the MN3007 in there, I think it's definitely worth powering it at 15V. Just make sure it's a solidly regulated 15V since you are pushing the limits of the BBD at that level.

Just to clarify max voltage is actually 16V with 15V typical, 18V is terminal, so there's a bit of play, just don't push your luck

[RobA]

If you've got the MN3007 in there, I think it's definitely worth powering it at 15V. Just make sure it's a solidly regulated 15V since you are pushing the limits of the BBD at that level.

Just to clarify max voltage is actually 16V with 15V typical, 18V is terminal, so there's a bit of play, just don't push your luck

Yep, I'm just a bit extra twitchy with these since they are getting to be difficult to source. But, I shouldn't overstate things. The extra few hundred millivolts that always seem to be there over the stated value for a regulator aren't going to hurt anything.

[wilsona]

Well I do have a spare 3007! And I also have a Road Rage - just don't think I can fit it in the box....