Popping Red Rooster (treble booster)

[elflicho87]

Hi everyone,
I've built a DAM Red Rooster clone using this (http://tagboardeffects.blogspot.it/2011/11/dam-red-rooster-vero-layout.html) layout as reference to draw my own PCB layout.



I used an ac128 so I wired everything as positive ground and included the 1M input pulldown resistor to ground. The pedal sounds amazingly good, but pops when engaged...
Something that I don't understand is why that 1M resistor is not placed at the very first place in the chain but after the range pot.

Could this be the cause of the popping issue?

If not, would an output pulldown resistor fix the problem?

If not (worst case), could it be my layout, with its components placing, to cause the noise?

Thanks in advance

Nic

[aron]

Hi Nic,

Check out this thread. It might help:
http://www.diystompboxes.com/smfforum/index.php?topic=69693.0

Aron

[induction]

Based on the vero: The range pot plus the 1M form a path to ground for the input, so no extra input pulldown is needed. However, the output cap has no pulldown. I would try putting a 1M or 2M to ground after the 10n to see if that solves the problem. You can put it on the jack for testing purposes (and you can keep it there if you want). In that case, go from pin 1 (top left) to pin 5 (dead center) or to any other non-switched ground point.

[elflicho87]

Thank you Aron and Induction.

You're right Induction, the input pulldown is doing its job, I was looking at it in a wrong way..
I'll try to add an output pulldown resistor and report the results when I find the time to put my hands on the pedal.

Since we are talking about pulldown resistors, I have another question: why most of the layouts/schematics out there usually have an input pulldown but no output pulldown?

Thanks again

Nic.

[induction]

Many pedals have a volume knob just before the output, which provides a path to ground and eliminates the need for an output pulldown.

[elflicho87]

Right Induction,  thanks.
Anyway, problem solved with an output pulldown resistor.
Thanks everyone.
Nic