Maxon SD9 help with traced values

[Marbles]

Hey Guys,

Hope someone can share a light on this :) A friend of mine owns a Maxon SD9 and loves the pedal. He is making 2 boards and asked me to build him an SD9. Layout is here, so all good to go!

He asked me if I could make it as identical as possible. I saw on the layout page there where a few different versions. I would ofcourse opt for the second one, cause his one has the transistor input and output buffers,

The (polarized) cap values confuse me though. First of all, both layouts have different values and the one I was planning on building has 3 here the other has 4

So I asked him top open his. He needs it a lot for gigging, so couldnt check myself, but guided him through it. These were the results:

Ceramic was 220pf as in the layout. Transistors c1815, but not as important I assume.

The cap values:

C105        0,47uf 50v
C112 10uf 16v
C118 47uf 6v
C119 100uf 16v


Now this is where I'm confused (not hard though). The 100uf is on both layouts. From power supply to ground, check.

But how do I explain the other 3?

Is the 10uf the 1uf in the layout? And is the .47uf the 47uf in the layout, and there's a 47uf that should be added somewhere else, or the other way around?


Hope this makes any sense whatsoever?

[Marbles]

A polite bump in the hope someone maybe knows?

[GrooveChampion]

Well, there is a good chance that the other three are not included since the layout here is usually simplified and is designed to work with mechanical true bypass. Dont forget that Maxon, Boss, Ibanez and pedals alike do not use mechanical true bypass, they use some sort of electronic buffered switches. There is a chance that the caps are not related to the signal path of the pedal itself but rather to the operation of its footswitch.

[Marbles]

Thanks for your reply!

There is only 1 extra, it seems. I think you're right, that one is possibly not even interesting for the circuit.

Only thing I'm wondering is: Which 3 of the values I have replace which 3 in the layout, and which would be left out. Comparing the 2 different layouts to my traced values I can't see what it would be :/

[GrooveChampion]

Well, in the layout there are 3: 47u, 1u, and 100. The only value that differs on yours is the .47u, which is sorta weird since I think its non polarized. I'd say it's the one that's 1u in the layout, but dont take my word for it. I am saying that cos it's the closest to the value of the original, presuming that your original matches with the traced vero layout, cos I tried looking up a schematic and it was all over the place.