So... I'm going to try to breadboard this... (Cornish P-2 Maybe)

[Fingolfen]

So... I like etching as much as the next guy, but it would be cool to eventually have a Gerber file or something, right???

I really love the Effects Layout Cornish P-2, but there isn't anyone I've found that makes it in PCB form. The base circuit is missing a lot of the Cornish buffer (though you can add that separately, but that's yet another etch). Also, there's no schematic with any of the Effects Layouts projects that I've found.

I'd read that the P-2 and G-2 used the same board (purported board below - I'm not going to rag on my own soldering jobs on hand etched boards ever again!), but based on the schematics I've seen there appear to be some differences



Taking matters into my own, completely incapable hands, I took a schematic off of an old Madbean thread, and then back traced it using the Effects Layout P2 I've built (a few times) as a guide.

Here's the original effects layout P-2



Here's what I've come up with by modifying the Madbean diagram...


Now I just have to actually manage to get this breadboarded and the schematic validated. I'd hoped to do this on my protoboard, but some of the parts are still out of stock at Tayda... So, it looks like I'm going with "the hard way" - wish me luck... (and or talk me out of it... *lol*)

 

[BuddytheReow]

SOme of the components, like the fuses, you won't need for this schematic. What parts are you missing?

 

[mdc]

The schematic you've put together has a BMP tone stack, I thought the P2 just had a LPF for the tone control?
You might have an easier time starting with a blank Big Muff schematic and porting the values over from the cornish pedal.
Will C6 and C9 work in that position? They're normally on the base side of the diodes, but I have no idea if it'll make a difference.

 

[Fingolfen]

SOme of the components, like the fuses, you won't need for this schematic. What parts are you missing?

I'll have to go back through, I know I'm missing the fuses. I also haven't picked up the SMDs yet.

 

[Fingolfen]

The schematic you've put together has a BMP tone stack, I thought the P2 just had a LPF for the tone control?
You might have an easier time starting with a blank Big Muff schematic and porting the values over from the cornish pedal.
Will C6 and C9 work in that position? They're normally on the base side of the diodes, but I have no idea if it'll make a difference.

So... let's be honest... I snagged the schematic off of Madbean and made it match Effects Layout board. The only changes were to R22 which is a 12K in the effects layout board, but was a 10K on the original (below), the diodes are 1N4148 in the EL version, but 1N914 in the Madbean, and the buffered version kept a 1M input pulldown resistor which is an 8K2 in the Effects Layout version.

As to the rest, I can't start with a blank muff and go from there because I don't have a P-2 to base it on - so I took a version of the P-2 that I know validates (I've built the EL version here). I also basically followed the trace of the actual etch backwards, so if you look at the 47nF capacitors (C6 and C9) on the perf / etch layout above, you'll see they are on the opposite side of the diodes from the 560pF capacitors and they are also connected to each other and VB through a 12K resistor.

Original schematic from Madbean:




Schematic with buffers from madbean:

 

[benny_profane]

1N4148 in the EL version, but 1N914 in the Madbean

These are functionally equivalent for our purposes. They have the same datasheet.

 

[jimilee]

So... let's be honest... I snagged the schematic off of Madbean and made it match Effects Layout board. The only changes were to R22 which is a 12K in the effects layout board, but was a 10K on the original (below), the diodes are 1N4148 in the EL version, but 1N914 in the Madbean, and the buffered version kept a 1M input pulldown resistor which is an 8K2 in the Effects Layout version.

As to the rest, I can't start with a blank muff and go from there because I don't have a P-2 to base it on - so I took a version of the P-2 that I know validates (I've built the EL version here). I also basically followed the trace of the actual etch backwards, so if you look at the 47nF capacitors (C6 and C9) on the perf / etch layout above, you'll see they are on the opposite side of the diodes from the 560pF capacitors and they are also connected to each other and VB through a 12K resistor.

Original schematic from Madbean:

View attachment 33686


Schematic with buffers from madbean:

View attachment 33695

I like what I see so far.

 

[Robert]

I have questions...

What are these "fuses" yall speak of?

The G-2 doesn't have the typical Muff tone control, and as far as I know there were no unpopulated components in the original?... Which means if they share the same PCB the P-2 likely also does not have the typical Muff tone control.

As far as I'm aware, both the Madbean and Effects Layouts projects are based on "best guess" schematics, not an actual trace of the original.

Which brings me to the final question.....

Why don't we just get one and trace one?

 

[Fingolfen]

I have questions...

What are these "fuses" yall speak of?

The G-2 doesn't have the typical Muff tone control, and as far as I know there were no unpopulated components in the original?... Which means if they share the same PCB the P-2 likely also does not have the typical Muff tone control.

As far as I'm aware, both the Madbean and Effects Layouts projects are based on "best guess" schematics, not an actual trace of the original.

Which brings me to the final question.....

Why don't we just get one and trace one?

Well, there's that...

Of course, there are around 650 reasons I haven't yet... Especially since I couldn't really justify it as a business expense...

 

[Robert]

Well yeah, of course, but that's not what I was suggesting.

I'm most likely going to be going out of town for a few days later this week... I don't want any packages sitting outside for days so I'll see what I can make happen as soon as I'm back.

 

[benny_profane]

Well yeah, of course, but that's not what I was suggesting.

I'm most likely going to be going out of town for a few days later this week... I don't want any packages sitting outside for days so I'll see what I can make happen as soon as I'm back.

But you’ll void the warranty!

 

[Robert]

But you’ll void the warranty!

I hadn't considered that..... nevermind, abort mission.

 

[benny_profane]

I hadn't considered that..... nevermind, abort mission.

Mission back on.

 

[Robert]

Warranty don't mean nothin if you just don't break it.

 

[howas]

As for a long time I’ve been trying different diodes and capacitors on my G-2 build with only some success, I would be happy to see a new trace

 

[benny_profane]

As for a long time I’ve been trying different diodes and capacitors on my G-2 build with only some success, I would be happy to see a new trace

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