Road Rage Grounding

[Bucksears]

I'm using the Road Rage as an internal voltage doubler in a chorus pedal, but have a question about grounding.
From the DC jack, the 9V(+) goes to the corresponding pad on the RR, but does the (-) on the jack just go to ground?
Long story short, the LED in my chorus pedal is wired directly to the 9V+ / - on the DC jack. I'm getting popping when I switch the effect on/off. I'm wondering if it's because the LED is 9V, the chorus circuit sees 18V and they're all on the same ground.

Any ideas?
Thanks,
Buck

[Thomas_H]

I'm using the Road Rage as an internal voltage doubler in a chorus pedal, but have a question about grounding.
From the DC jack, the 9V(+) goes to the corresponding pad on the RR, but does the (-) on the jack just go to ground?
Long story short, the LED in my chorus pedal is wired directly to the 9V+ / - on the DC jack. I'm getting popping when I switch the effect on/off. I'm wondering if it's because the LED is 9V, the chorus circuit sees 18V and they're all on the same ground.

Hi Buck,
You have wired it correctly.
If you want to find out if the LED causes the popping, why dont you just disconnect it from the jack (one side will be enough) and check if it still popps?

[Bucksears]

Thanks Thomas - I had that planned out this morning, after thinking about it a bit more.
The odd thing is that the popping is intermittent. I'll disconnect the LED tonight and report back.

[RobA]

Which chorus is it and what layout did you use? I'm asking because many of the choruses are adapted from buffered switching pedals and then don't have pull-down resistors on the input.

[Bucksears]

Excellent point.
This is actually a reverse-engineering that I did of an Ibanez CS-505.
I removed the buffer/switching portion, wired it up with true bypass, added a trimpot at the end (to adjust the volume boost) and have it powered with 18V using the RR.

I didn't add the 1M pull-down at the input, so that could very well be it. Thanks!

Side note: the 505 sounds awesome. Incredibly close to the vintage one I used to have.

[RobA]

Ooh, that's very neat. Which IC is the CS-505 based on? I've got a schematic for the CS9, but not the 505.

It could be the pull-down will solve your problem. You might be able to try it out by tacking one onto your foot switch.

[Bucksears]

Ooh, that's very neat. Which IC is the CS-505 based on? I've got a schematic for the CS9, but not the 505.

The CS-505 is based on the MN3007/MN3101 combo. Everything else is pretty standard op-amps.
It's by far the most difficult build I've ever done; I have the CS-505 service manual and created a new PCB that would fit in a 125-B enclosure. I removed some tracings that weren't needed and moved a few pads around to get it small enough. There were some oddball cap values that I had to special order and some transistors/diodes that I had to get modern equivalents of, but it's done and works 100%.

[Bucksears]

Thanks again - the 1M pulldown resistor worked like a charm. Switching is dead silent.

[RobA]

Thanks again - the 1M pulldown resistor worked like a charm. Switching is dead silent.

Excellent! I'm glad it worked. That had to be a ton of work to get the whole thing reverse engineered and the PCB designed. Congrats!

[Bucksears]

Excellent! I'm glad it worked. That had to be a ton of work to get the whole thing reverse engineered and the PCB designed. Congrats!

Yeah, I traced it all out in Adobe Illustrator (CS6), scaled it to size, printed out on PNP blue, blah-blah-blah.
Next one I'm working on is the Ibanez Classic Flange FL99.