Why do pedal makers “goop” their circuits?


Why do you sometimes see pedal makers “goop” their circuits? To prevent user mods? Protect circuit design and help prevent clones? Keep components secure and less prone to failure? All of the above? Some of the above? I don’t see a lot of this but got curious when I opened up my two Greer pedals. View attachment 298469
All of the above but i think it's gotta help keep the components secure when the pedal gets knocked around. Seems like a good idea until it needs a fix or mod.


Nuzzled Firmly Betwixt
Platinum Supporting Member
Someone mentioned ground loops or noise floor.
If anything, the addition of a material that (likely) has a surface-fluid resulting from the curing process will
INCREASE the noise floor or the potential for ground loops, via either trace-resistances or parasitic capacitances.

Conformal Coat is an entirely different thing.... but that ain't no conformal coat.


It's all well and good if the builder is not too far away but being on the other side of the planet makes it uneconomical to send my gooped Magnavibe on a 'round the world trip

Bill Lumberg

I Drink and I Know Things.
I prefer the way that Caroline Guitar Company used to do it. They simply printed on the edge of the circuit board "Please Do Not Post Gut Shots Online" or something to that effect. We've seen goop for years as well as builders scraping the info off of IC's & caps and removing rings from resistors to prevent circuit cloning.


Gold Supporting Member
I think the practice is fading. People used to think that it protected IP/the emperor's clothing, but freestomboxes.org has as good a record reproducing gooped pedals as ungooped (although the REALLY expensive ones have presented a problem in terms of how to pay for breakage). Most folks know it only slows things down.

As for increased durability, the failure modes of modern pedals are:
1. Switch
2. Hardware: pots or jacks
3. Solder failure (either dry joints or cracked joints)
4. Component failure

The only one of those likely to be helped by goop is 3, and 1,2 and 4 may be made more difficult. So the "it's for touring strength" crowd is fooling themselves, I think. OTOH, Pete Cornish, who's been building the same basic pedals for decades and must know they've been traced, uses goop to stabilize his boards (it's pretty thin so it shouldn't prevent repairs) and they apparently last forever?


Silver Supporting Member
Generally, there are two reasons:

1.) There is something unique and proprietary to the circuit and the builder doesn’t want people to copy it. Particularly since it’s difficult (and expensive) to get patents on many effects circuits.

2.) The circuit under the goop is itself a copy of something else and the builder doesn’t want people to know that it’s something else.

Either way, it’s usually done because builders believe it offers them protection from prying eyes.
You Can't Hide Your Prying Eyes.


This Is Fine.
Platinum Supporting Member
Lets just say there is a reason you should wear a mask and be in a well ventilated area when soldering.... i mean look at the “business model” of some of these guys. They need to get out more.

Gooping doesn't accomplish anything aside from making mods and repairs more difficult.
Not true.

The RTV or silicone damps vibration, which in turn prevents cracked solder joints.

I owned a racing data acquisition company for a while, and every product that went out the door was filled with clear silicone. Without the silicone, none of the PCBs would have lasted more than a few laps in a formula car; with it, they lasted years.

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