First build component sourcing

J

JimmyS2

New member
Hi all!

Ive picked up a few boards to try building some pedals, only ever did a BYOC kit like 15 years ago. I think back then I tried a second pedal, it didn't work, and i decided not to worry about it anymore.

Anyway, last night I was going through the build docs and trying to put together an order from Tayda, I've done some research on component selection that helped a bit.

My question so far, is about selecting op amps. I'm building the Increment, a Barber Plus od, and it specifies "JRC072DB" which seems to be hard to find. Since I'm new, I don't know if there are obvious substitutions, or if any dual op amp will behave about the same. If I need to track the exact part down I will, ebay maybe?

If anyone has either some insight about what I can/should use, or where I might find it, that would be greatly appreciated!
 
It's just a TL072 made by Nishimbo/japan radio corp instead of TI. Mojo where it doesn't really need to be.

You could really use any dual op amp. The TL072 is cleaner, among other specs, over a 4558 or something like that, but almost aby dual will do
 
Here's one more question while im working my way through it.

The increment overdrive specifies a couple of "2D503B" diodes, which i couldn't find on tayda, and the BOM includes a link for them to PPCBs listing. This is handy, but again with a strangely hard to find component I wonder if it's actually necessary to have the exact thing, or if there are functionaly equivalent substitutions and I just don't know what I'm talking about yet.

If I'd gotten everything figured out ahead of time I could have just thrown those in with my order, i guess at least I've learned THAT so far.
 
There appears to be a little unicorn magic with those diodes and it's particular curve..... That being said you could also use some silicon diodes that are readily available as well with .68-.79 FV and be in the same territory of clipping...
 
Wow. I appreciate that, although I don't really know what I'm looking at yet. This is exactly the type of information I enjoy in other hobbies once I'm well down the rabbit hole. Hopefully I can get the first few builds working well and see how i feel, I do love a good graph/chart once I feel like I can get my head around it.

Thanks for the responses guys, very welcoming and helpful to a complete newcomer, I appreciate it.
 
To me it looks like the KD503A would be very close to the 2D503B, based on the graph. It's easier to see them if you click to disable a lot of the ones further away (so the beginning and end of the list). KD503A seems to be available in Europe at least, from a bulgarian webstore and a 100pcs lot from Ebay.

As for how big the difference would be if you just used 1N4148's instead... probably not very big. It's asymmetric so preferably you would switch them with something else if you want to keep the asymmetry, but to be honest in a lot of situations the clipping diodes don't make a huge difference in sound. There is some difference between big jumps (eg. something that clips a lot and something that clips a little), but as long as you're sort of in the ballpark it's quite hard to hear the differences, usually, in my experience.
 
To put this (exact component selection) in historical perspective, especially early on, some companies were very loose with selection. If they could get a good price on a part that was a bit off spec, then that run used that part. This is one reason why certain era pedals are more desired. Electro Harmonix was infamous for this.
 
Thats a good point, I'm sure for things that where in production a long time part availability for components probably shifted over time leaving the legends and lore of certain specific vintage things being superior for mysterious reasons.

While I'm sure substituting components is probably often totally fine and not even unlike the original, I guess I'm still just intending to learn. That way I only pull a quick part sub when I know it's ok, and I know the reason it's ok.
 
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