Messages

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....

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.

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.

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.

Same issue with a different PSU. Will give the capacitor suggestion a try. I do not have one that size around - how close does it have to be to 100nF?

Thanks for feedback - I have not had time to open it up and tap around yet. The power supply is 9V from an MXR Brick. I'll try a separate 9V wallwart and see if it is any different.

Skeleton jacks. I'll open it up and try tapping things.

Well everything on mine is plenty tight... I do notice the case is a bit microphonic, tapping it comes through - what could that be?

Can't see you pictures. I had a similar problem: the input on pin 3 to the 3007 was there but there was no output on 7 and 8, turned out to be a bad connection in the jumpers area, finally tracked down with a multimeter  - what revision is your PCB? If you can trace the audio then you can narrow it down. Posting IC pin voltages might throw up some ideas.

Just had an epic tussle getting my Pork Barrel working (it was a dodgy connection on the PCB). Now I have a problem with noise.

The LFO has an audible tick that varies with the the rate - does anyone have any idea on how to get rid of it? It is loud enough to make the pedal unusable. Otherwise it is fine, although it does not like being driven and distorts a bit. Plenty of depth.

I have already tried shielding the pots and signal wires from the PCB with copper tape and checking everything is grounded OK.

Help (again)!

I do have a spare road rage board, might have a go, although not much room left in my case.

I've just added the depth LED mod but not as good as I hoped - the LED flashes and gets more intense but the depth seems less. Will lookup the tonepad cap mod. Can hear the LFO ticking in background, need to look into shielding.... 

This Italian company do a kit: http://www.aresaudio.com/picolooper3.html

Thanks for your help - zeroing in on the output voltages got us there in the end.

Yes - I might look around for another chorus board that uses that combo. Got PCBs for trembulator, cupcake, runt, rangemaster and bloviator (?) to keep me busy - already built an Umble, Afterlife and an 'order flipper'. My pedal board is now too small! Would love to build a fully featured multi loop pedal management project, not seen anything that ambitious in the hobbyist realm yet.

Yeehah! Found it. At last. Thanks everyone for all of your help in narrowing it down and pointing me in the right direction. I have learned a great deal about debugging and to be honest, although tearing my hair at times out I have quite enjoyed the process.

Don't know whether it was a PCB fault or the result of my inexpert soldering and subsequent redoing of the jumpers, but the pad on the jumper indicated on (blurry) attachment was not making proper contact with the track. I bridged it with a little solder till I got consistent continuity between all points. Once assembled again readings on pins 7 and 8 were just under 4V as required.

Pedal is now working.  Does not like to be driven with a high input however. Distortion evident at a fairly low level. I'll try it before my compressor. Sounds great though, brings back a lot of memory associations. Ah, the 70's!

Thanks again for all of the help, I am am extremely grateful.

Might need  comma in that sentence. I am reading it as -

"pin 5 going to ground, and pin 1 and one side of R20 connected to pin 1 of the MN3101"

I have:

One side of R20 is the same as 7 and 8 of 3007.
Pin 5 of 3007 -> gnd
Pin 1 of 3007 -> one side R20

I do not have one side R20 -> Pin 1 of 3101

R20 one side relative to gnd measures 6.6V - same as 7/8 of 3007. I presume this is what to expect.
Across R20 measures 1.95V
The other side relative to gnd measures 8.7V

I don't really know what that means, tbh.

I redid the jumpers area and replaced the 3101 socket, reflowed all socket pins - unfortunately I do not know which pads to check that jumpers are connected properly.

I think I only have an 18V PSU around, I'll have a look.