Paper Scratcher OpAmp

[Bricksnbeatles]

Is the OPA1678/OPA2134 really necessary for the Paper Scratcher fuzz? It seems like a waste to use such an expensive “hifi” chip for a fuzz— I’m guessing a TL072 or LM1458 would sound the same given the applications. I’ll build it with whatever dual op amp I have on hand, but I’m wondering if it’ll actually be worthwhile to order one of the fancy expensive $5 op amps that the build calls for and swap it in at a later date

 

[benny_profane]

Have the hifi chips for stock. This certainly does not need it though.

 

[Alan W]

Since you’re probably going to socket it anyway, definitely start out with a more mundane op amp. For “clean” boosts I typically really prefer the Burr Brown designs, but I know when I subbed them for the 4558s in the Axon Andromeda, I was surprised at the drop in audio quality—I decided there was something specific to the circuit (support capacitance?) that the 4558 either didn’t need, or? (Whatever it it beyond my current understanding). I guess what I’m saying it, there may be a viable reason that the design calls for that specific op amp. Does seem odd though. When you do have a 2134 (say for a General Tso, or whatever), it’ll be worth dropping it in to see what the changes, if any, in that circuit is.

 

[Bricksnbeatles]

Since you’re probably going to socket it anyway, definitely start out with a more mundane op amp. For “clean” boosts I typically really prefer the Burr Brown designs, but I know when I subbed them for the 4558s in the Axon Andromeda, I was surprised at the drop in audio quality—I decided there was something specific to the circuit (support capacitance?) that the 4558 either didn’t need, or? (Whatever it it beyond my current understanding). I guess what I’m saying it, there may be a viable reason that the design calls for that specific op amp. Does seem odd though. When you do have a 2134 (say for a General Tso, or whatever), it’ll be worth dropping it in to see what the changes, if any, in that circuit is.

Definitely makes sense. Fancy chips like that are worth giving a try for clean boosts and comps, where the “hifi” characteristics have some logic to them, but I couldn’t really imagine that a janky, 60s garage rock style fuzz box would have much benefit from one chip to another.

 

[coltonius]

I built a Paper Scratcher but didn’t socket due to clearance while shoehorning it into a 1590B. I do find it odd that EHX would include it on a budget pedal if they didn’t need to..

I’m anxious to hear the results of socketing, as my preferred opamp for buffer stages is the trusty TL072!

 

[Bricksnbeatles]

I built a Paper Scratcher but didn’t socket due to clearance while shoehorning it into a 1590B. I do find it odd that EHX would include it on a budget pedal if they didn’t need to..

I’m anxious to hear the results of socketing, as my preferred opamp for buffer stages is the trusty TL072!

Yeah, they use much cheaper op amps in many other pedals. It seems odd they’d choose one that’s so much costlier per unit when it’s not one they use in many other pedals afaik.