Installing a pedal into a guitar?

[bifbangpow]

Hey guys. So I have a friend who is building a guitar and requested that I install a chorus pedal into the actual guitar.  I'm just trying to crank this one out and he chose this pedal :http://byocelectronics.com/analogchorusschematic.pdf 
I'm wondering how to connect it to the guitar signal.  I'm guessing the pickup needs to connect to the input somehow and then the output can just be the actual output of the guitar... but a bypass switch will be needed.... Can anyone help me?

[ElectricDruid]

If I were you, I'd dump the on/off indicator LED and use a DPDT toggle for the chorus on/off bypass switch. Finding some sort of 3PDT switch you can use in a guitar is going to be difficult and anyway, what's the point? With a toggle, you know what it's doing because of the position it's in, so you don't need an LED as well - unlike a foot switch.

So:
SW 1A pin 6 goes to ground directly, rather than via SW 1C.
SW 1C disappears.
R28, R29, Q4 and D1 (the LED) can all be left out.

How big is the BYOC PCB for this pedal? Is it realistic to get it and a battery inside a guitar?

Tom

[bifbangpow]

If I were you, I'd dump the on/off indicator LED and use a DPDT toggle for the chorus on/off bypass switch. Finding some sort of 3PDT switch you can use in a guitar is going to be difficult and anyway, what's the point? With a toggle, you know what it's doing because of the position it's in, so you don't need an LED as well - unlike a foot switch.

So:
SW 1A pin 6 goes to ground directly, rather than via SW 1C.
SW 1C disappears.
R28, R29, Q4 and D1 (the LED) can all be left out.

How big is the BYOC PCB for this pedal? Is it realistic to get it and a battery inside a guitar?


Tom

That sounds great! I will try it.  Yeah the board is fairly small. I mean... fits inside a 1590 B enclosure. But the guitar they are building is a large electric cigar box guitar. He's just making something silly for fun. So as long as it fits and works it shouldn't matter much.

[Mark Hammer]

The annual I want-to-build-a-pedal-into-the-guitar post.

I understand the cool factor of doing so, but note the following caveats/considerations:

1) How will ity be powered?  Will you need to get in there to change the battery often?  Will it be difficult to do so, and will any screw holes be compromised by regular unscrewing?

2) Is there room for the board you intend to install?  Most guitars will have enough spacer to accommodate a simple 2-transistor fuzz, but chorus effects take up more real estate, and maybe more than you have available.  Check the footprint of whatever layout you intend to use.

3) Can you provide adequate shielding for the effect?

4) There will not be any way to insert anything ahead of the chorus that might be useful in making the chorus sound its best.  If it is the only effect your buddy ever intends to use, fine,, but chorus is one of those things you likely do not want to follow with high-gain stuff that boosts whatever clock noise the chorus generates.

5) Can the chorus be done better in a box than on the guitar?

6)  It won't add a lot, but it does add weight, when pots, knobs, switch, board, parts, and battery are added into the mix.  Sometimes another 4-6oz makes a difference in player comfort.

7) Is there a convenient spot to install whatever controls are intended?  Is there a risk of crowding the space, or accidental misadjustment?

On-board effects are a bit like bicycle lanes in big cities.  If you plan for their inclusion from the get-go, they can work well, providing safety and convenience.  If you try and shove them into an area that was designed around NOT having them, they can be problematic.

[Juan Wayne]

Stupid question: what guitar is it?

It's not that big of a board, and with SMD components you can make it stupid small (you need electrons that are not claustrophobic though, so has the internets taught me). Push pulls and/or concentric pots might save you from drilling anything, batteries can be fit pretty much anywhere, the consumption of that exact pedal without the LED should be around 16mA (according to a very similar one I happen to have tested, also based on a CE-2) so battery like shouldn't be that big of a deal... I mean, it can all be done.

There's all the other stuff that was mentioned that says "no", though. No to pee on your friends idea, I know people have installed damn iPads on guitars (see Matt Belamy), but a chorus as the very first effect is something to really think about. After all, there's a reason why these ideas never really take off out of the custom job world, except for the Firebird X, which I learned from Henry J******itz it's still the unavoidable future.

[italianguy63]

You could fit a ton of stuff in a Telecaster "Smuggler" body!   

[bifbangpow]

To Mark and Juan,

as I mentioned in a comment above, it's a silly cigar box guitar. With a big deep box. SO though I understand your conccerns, it's just a for fun project. 
DON'T CRUSH MY SPIRIT!!   

[Marcos - Munky]

This one you've linked to uses an MN3007. It's an obsolete IC, it's somehow rare to find an original, and you'll find a lot of conterfeits. What about the Little Angel chorus? This one uses a PT2399, which is a cheap IC, and there's a verified 1590A layout at the Little Angel thread.

[Mark Hammer]

To Mark and Juan,

as I mentioned in a comment above, it's a silly cigar box guitar. With a big deep box. SO though I understand your conccerns, it's just a for fun project. 
DON'T CRUSH MY SPIRIT!!   

Merely trying to avoid disappointment.  But if the bar is being set that low, there is nothing to be disappointed about!

So get to it! 

[Juan Wayne]

To Mark and Juan,

as I mentioned in a comment above, it's a silly cigar box guitar. With a big deep box. SO though I understand your conccerns, it's just a for fun project. 
DON'T CRUSH MY SPIRIT!!   

Whooops, my bad, I swear I read through the whole thing and for some stupid reason I missed the key part. Hey, have at it, it would be fairly simple if you're dealing with a blank thing to begin with.

Just a couple things about it.

Marcos - Munky is right, the 3007 is not impossible to get, but it will be harder and more expensive to get than the MN3207. The MN3207 is basically the same BBD on positive voltage, and unless you're thinking about running the effect at a higher voltage, which the MN3005 allows you to, you wouldn't notice much of a dynamic range difference nor signal to noise ratio.

You will have to revert polarity on the BBD looking at that schematic, which only means Vb goes on pin 5 and Ground to pin 1 of the 3205. I actually worked on a chorus a couple month back and that's exactly what I did. It's based off the CE-2 like this one. You might want to check out some late schematics of the CE-2 and other clones to have a reference of how they swapped from 3005 to 3205 when it became obsolete. Also, breadboard it frst just in case there's some biasing issue I'm overlooking right now, but looking at the schematic I think that's it. In fact the old BYOC Analog Chorus (CE2 Rev. 11 Schematic) has that exact variant and a slightly different power section. I don't know why they went back to the 3005, vintage love I guess.

About connecting it, just go business as usual on the electronics of the cigar box, then before going to the jack, pass through a DPDT toggle switch that would act as the footswitch, and then straight to the jack. This kind would look cool and chunky enough, there's a DPDT version somewhere:


You will still need 2 extra knobs, but if you want to keep the simplistic look, you might luck out on some concentric pots. I'd go Les Paul layout, with 4 knobs and the toggle switch on the top.

[Rob Strand]

A bit OT but I saw a video where Chris Squire had a bass with effects build in.

Approx 21:25
https://www.youtube.com/watch?v=cprcYnffK_o

Looks like it has toggle switches.

[bifbangpow]

Marcos - Munky is right, the 3007 is not impossible to get, but it will be harder and more expensive to get than the MN3207. The MN3207 is basically the same BBD on positive voltage, and unless you're thinking about running the effect at a higher voltage, which the MN3005 allows you to, you wouldn't notice much of a dynamic range difference nor signal to noise ratio.

You will have to revert polarity on the BBD looking at that schematic, which only means Vb goes on pin 5 and Ground to pin 1 of the 3205. I actually worked on a chorus a couple month back and that's exactly what I did. It's based off the CE-2 like this one. You might want to check out some late schematics of the CE-2 and other clones to have a reference of how they swapped from 3005 to 3205 when it became obsolete. Also, breadboard it frst just in case there's some biasing issue I'm overlooking right now, but looking at the schematic I think that's it. In fact the old BYOC Analog Chorus (CE2 Rev. 11 Schematic) has that exact variant and a slightly different power section. I don't know why they went back to the 3005, vintage love I guess.

I all ready have the 3007. So I'd like to stick with that. But as for reversing polarity on the BBD, so I can just flip the the chip around? I ask because I'm not etching this board (he gave me a pcb) so I want to be certain of what I'm doing. Flipping it around wont effect the pin3 and 8 connections?  sorry still learning.

[bifbangpow]

If I were you, I'd dump the on/off indicator LED and use a DPDT toggle for the chorus on/off bypass switch. Finding some sort of 3PDT switch you can use in a guitar is going to be difficult and anyway, what's the point? With a toggle, you know what it's doing because of the position it's in, so you don't need an LED as well - unlike a foot switch.

So:
SW 1A pin 6 goes to ground directly, rather than via SW 1C.
SW 1C disappears.
R28, R29, Q4 and D1 (the LED) can all be left out.

How big is the BYOC PCB for this pedal? Is it realistic to get it and a battery inside a guitar?

Tom

I'm still learning how to translate between shematics and actual circuit layout.  Can you answer this for me real quick.  Based on the schematic below, are the circled resistors on the actual PCB the R8 and R9?

[Juan Wayne]

Marcos - Munky is right, the 3007 is not impossible to get, but it will be harder and more expensive to get than the MN3207. The MN3207 is basically the same BBD on positive voltage, and unless you're thinking about running the effect at a higher voltage, which the MN3005 allows you to, you wouldn't notice much of a dynamic range difference nor signal to noise ratio.

You will have to revert polarity on the BBD looking at that schematic, which only means Vb goes on pin 5 and Ground to pin 1 of the 3205. I actually worked on a chorus a couple month back and that's exactly what I did. It's based off the CE-2 like this one. You might want to check out some late schematics of the CE-2 and other clones to have a reference of how they swapped from 3005 to 3205 when it became obsolete. Also, breadboard it frst just in case there's some biasing issue I'm overlooking right now, but looking at the schematic I think that's it. In fact the old BYOC Analog Chorus (CE2 Rev. 11 Schematic) has that exact variant and a slightly different power section. I don't know why they went back to the 3005, vintage love I guess.

I all ready have the 3007. So I'd like to stick with that. But as for reversing polarity on the BBD, so I can just flip the the chip around? I ask because I'm not etching this board (he gave me a pcb) so I want to be certain of what I'm doing. Flipping it around wont effect the pin3 and 8 connections?  sorry still learning.

Nothing wrong with learning, we all are till we either die or learn how to levitate (I don't know about you, but the day I learn to levitate I'm done, no new knowledge will be required).

I was just referring to pins 1 and 5 on the MN3207 when using it to replace a 3007 on an identical circuit. But, since you already have the PCB and the "good" chip, carry on with it. Plus, I've been secretly gassing for a cigar box for years, so I'd love to see how this project turns out.

[Fender3D]

About connecting it, just go business as usual on the electronics of the cigar box, then before going to the jack, pass through a DPDT toggle switch that would act as the footswitch, and then straight to the jack. This kind would look cool and chunky enough, there's a DPDT version somewhere:

You may ask Richie what footswitch uses here:



...and this the day the footswitch fails...