Chop Shop: "Scrub Jay Overdrive"

[rwl]

Build Rating

4.00 star(s)

This is a a report on the Chop Shop OD, based on the Fairfield Barbershop. This pedal showed up on some pots in the original Top Five thread and is pretty consistently recommended on this forum, so I wanted to see what all the fuss was about.



Inspiration
I was originally going to give this pedal a Barbet theme - an obvious play on the Barbershop name (e.g. something with this bad boy - Barbets are tropical finchlike birds). The bird is dope but I was really struggling with the background, because I wanted to give it a barbershop pole kind of look, and the whole thing felt really garish.

Then I saw a "request" for a scrub jay design in this thread, and figured that there's some kind of overlap there. Maybe it's more in my head but I just had this image of a barber sweeping up hair from his shop. Scrub Jays are visible in the pacific northwest, but it's more of a rarity - whenever we see them rather than the more typical Stellar's Jays, we stop and take a look. I like them, but perhaps they're my third favorite jay (after Stellar's Jays and Blue Jays). I do like that Jays in general are very smart birds - they're corvids, so they're in the same family as crows and ravens.

But then Scrub Jay theme was also a bit of a struggle for me. I knew I wanted the pun of the bird to actually be "scrubbing" something, so it was a given it would be holding a mop (the Scrub Jay is named after the scrub ecosystem). Then I started feeling I'd like a coniferous forest background, but it all felt cluttered and I just wasn't inspired. That design looked something like this (not final, I would have improved contrast a bit):

Pretty, but more of a poster than a pedal and I've started to steer clear of that concept - not avoiding it 100%, but definitely leaning more into "pedal" aesthetics that feature a more prominent central image.

Then it hit me, the jay needs to be scrubbing something. Why not lean into the messiness and dirt of pedals? So I went with the stained kind of background, left the jay on its branch with the mop, and I'm very happy with it. It's a simpler layout and makes the scrubbing theme more obvious. There's a UV print across the entire front, which I would probably avoid in the future, but I wasn't sure whether the stains would blend poorly with the Tayda background I chose (cream).

The Build
It's an easy build (not many parts, easily obtainable). I used Aion's J201 through-hole adapters here, but were I to build this again, I'd just use the SMD J201 pads that are on the board (as I have with some subsequent circuits). Soldering SMD transistors isn't my favorite thing, but they're not that bad, cheaper, and can be obtained from the more usual stores.

I really struggled with biasing the pedal though. Apparently Fairfield (and PPCB) reversed the function of the sag knob between pedal versions, so old instructions on the forum got out of date. I think this was also the first time I biased a pedal by measuring actual voltage with a DMM. Plus it was hard to know what this pedal "should" sound like at different settings. For that reason, the build was frustrating, but at least I didn't have to do much disassembling or debugging beyond figuring out how to bias.

I detailed my investigation into biasing in this thread, where @Fish encountered the same problem at the exact same time that I did, and @temol provided some helpful advice.

It's not a particularly noisy pedal, but I figured I'd give this one the deluxe treatment and use shielded wires for the input and output since it's a favorite. It looks messier since they don't stay put when bent, but it does decrease background noise.

The Pedal
I love it. It's currently in my "top five." I've played with it more since reboxing it in a printed enclosure and I like the natural overdrive setting. But to my unsophisticated ears that doesn't necessarily distinguish the pedal from other overdrives. What I like to use it for is to clean up other overdrives, with some of the knobs are rolled back. It's subtle but noticeable. My favorites are with the Paragon and the Glory Hole. It sounds great and if you turn it off and listen to those pedals on your own it immediately sounds worse. And if you come back with fresh ears and start playing those pedals on their own again, they sound great... but turn on the Chop Shop and they sound amazing again.

I think sometimes a second overdrive that "cleans up" the ones in front of it can end up being kinda harsh or trebly or grating after a few minutes, but I haven't noticed that with the Chop Shop.

Firsts

• First time biasing with DMM
• First theme "requested" by a forum member (@Erik S )

Build rating: 4/5
Pedal rating: 5/5

 

[Erik S]

I love it! That's a good lookin bird, and I like how it pops a little more without the full background art.

I also put this one in my wishlist after that top 5 thread. Once I clear out some backlog, that one will definitely be in my next purchase.

 

[CheapSuitG]

Great build! Love the look!

 

[ThatDude]

haha, Scrub Jay ready to scrub. Cool build! I also ran into the biasing confusion like you did when I built this circuit. It was worth figuring out though. Its probably my favorite light overdrive. I use it so there's light overdrive when playing a bit more forte, but when I lighten my touch it cleans up. That's basically my "clean" sound. I'll have to try it out the way you're using it. Thanks for the scoop!

 

[MattG]

Looks great, as always!

The bird artwork on all your pedals - is that all original artwork that you do yourself?

Blue Jays are pretty common around me. They are pretty, but also kind of jerks. I remember when I was a boy, we had these big rubber bowls outside for feeding the dogs (they were actually meant for feeding hogs). Anyway, in the winter, birds would always sit on the rim of the bowl and eat the dog food. All different kinds of birds - until the blue jays showed up. The jays would aggressive peck at the other birds and scare them away, until it was only the jays on the bowl.

How do you guys strip shielded wire? I generally only use shielded wire when absolutely necessary because I find it such a chore to strip. I'd probably use it in more pedals if I could figure out how to strip it more easily.

 

[rwl]

The bird artwork on all your pedals - is that all original artwork that you do yourself?

The birds are basically all original artwork, but it might depend on your definition of original. Occasionally I use Gemini to see if I can get a good pose, otherwise I'll look for a photograph with the pose I want. Then I do a sort of tracing on top of those to reduce it to a narrow range of colors and clear smooth outlines, remove gradients, as well as cleaning up the outline, slight rearranging. I would say this typically takes about 60-90 minutes per bird. The limited number of colors and detail means I can repose easily with my limited art skills, like moving heads or wings, without it looking bad. For example, in this case, the bird's wing wasn't out and it wasn't holding a mop, so that was drawn from scratch . Also the limited colors read clearer and is better I think for UV prints.

How do you guys strip shielded wire?

I was worried it would be tough, but it's actually pretty quick. I use this wire, recommended I think by someone else on the forum. I have Irwin automatic wire strippers (these). Absolutely worth the price. First I set them for about double the normal length I'd strip, and strip both ends like that. This removes the black outer insulation. Then I take all the shielding strands and twist them together, perpendicular to where I started the strip, and getting every single stray wire. This exposes the inner insulation. Then I set the wire strippers to the normal length and strip the inner insulation. In both cases I do nothing unusual, the strippers will just take off one layer of insulation. On the footswitch end I optionally trim the shielding, and then add electrical tape around the shielding wire to completely hide it since only one side should be grounded.

On the audio jack, I solder the signal side as usual, then stretch the shielding wire over and solder it to the ground on the audio jack.

The last step is the only painful part as the audio jacks I use don't have holes large enough to fit the grounding from the board and from the shielding, so I just kinda glob solder on to hold it all in place. Also if the shielding wire stretching across is too taught, it's possible when inserting the audio jack that it might just touch the wire. So I probably should add electrical tape there as well.

 

[Einzeln]

I play my ac30 with the normal channel. From all my DIY pedals the Chopshop, green Ringer, and Rub a dub never left my pedalboard.

 

[MattG]

The birds are basically all original artwork...

I'd call that original. Your "style" is instantly recognizable and I think looks really good on pedal enclosures!


As for stripping shielded wire, I have those same strippers (and yes, fully agree, 100% worth the cost, although they don't seem to work on teflon-coated wire).

Then I take all the shielding strands and twist them together, perpendicular to where I started the strip, and getting every single stray wire.

This is the part I find to be tedious and time-consuming. I've never tried with the particular wire you're using, maybe the shielding "de-braids" more easily than the stuff I have?

So I probably should add electrical tape there as well.

Well-planned heat shrink tube is generally the neatest solution, but that's not always doable. I almost never use electrical tape these days, except for temporary hacks. When I can't (or forget to) use heat shrink, I use self-amalgamating (aka self-fusing) tape (this is what I bought). It's expensive, but so much nicer than electrical tape.

Additionally, while I don't actually have any of this, I know you can buy small diameter teflon tubing, which you can just slide over exposed wires. It's kind of the same idea as heat-shrink tube, but you don't shrink it; and being teflon, it won't melt when you solder the wire you put in it.

 

[rwl]

Well-planned heat shrink tube is generally the neatest solution, but that's not always doable.

What do you use for the heating? And what size tubing? I should use heat shrink tube, would be a lot neater. But I've avoided because I didn't want to spend much on a tool for heating.

 

[MattG]

What do you use for the heating? And what size tubing? I should use heat shrink tube, would be a lot neater. But I've avoided because I didn't want to spend much on a tool for heating.

Just a regular old aim-n-flame that I also use for lighting my grill. I believe you're not supposed to put a direct flame on heat shrink tube, but I get the flame going and make quick "brush strokes" with it across the tubing. The latest grill lighter my wife bought is even nicer, it's one of those "jet" style torches, where the flame is barely visible. But until recently I've always used a disposable cigarette lighter type flame.

Although I haven't actually done this, if you have a steady hand, I think you could also just get your soldering iron tip close to - but not touching - the heat shrink tube.

As for the size: the tubing should say how much it shrinks. But I just buy a heat shrink kit with a variety of sizes, and I always use the smallest size that I can actually slide over the work.

 

[ThatDude]

What do you use for the heating? And what size tubing? I should use heat shrink tube, would be a lot neater. But I've avoided because I didn't want to spend much on a tool for heating.

I bought this assortment of Heat shrink tubing like two years ago and still have a lot left. I typically cut pieces even though the pieces are already small. It makes it last longer. It's relatively cheap but it gets the job done.

For heat I use a mini heat gun similar to this one, it's small so its not great for use on things like automotive projects, but its perfect for heat shrinking amps, pedal projects, cables, etc and general smaller applications.