BOSS CE-3 famous R18 resistor

[yelemusic]

Hi there, first time poster here. Though I've been reading on here occasionally.
Hope this is the right forum for my request.

Anyway, I acquired a BOSS CE-3 Chorus pedal for cheap, so obviously I didn't reject it.
Upon research I found out that this particular pedal drops in volume when engaging.
Apparently all that's required is removing resistor 18, so it wouldn't drop in volume.

So I thought, easy enough, I'll find R18 and snip it off (though some people suggested replacing it with another value, others said that just removing it altogether would do the trick). Can't be that difficult.
Now here's the thing: The resistors aren't marked on the PCB board. Plus I'm a total idiot when it comes to reading schematics, which doesn't help. I like to tinker with things, but I don't know anything about electronics. I did however manage to put some Billm mods into my Blues Junior amp (those who've got a BJ know what I'm talking about )  (I also managed to do the bright cap mod on my Vox ac4, which was quite scary really, but worked like a charm)

I couldn't find ANY pictures on the internet showing said R18, so I thought, surely somebody here must have done this mod in the past and would be willing to take a picture of the PCB with the R18 (or the lack thereoff) marked, so that I can easily identify it and snip it off.
I hope I'm not asking too much, but I'd really like to use the pedal. The way it behaves now is just not practical. It honestly gets a few db quieter when engaging.What did the engineers at BOSS think?

Looking forward to as many replies as possible

Thanks in advance

[rainless]

Here's a schematic of the pedal. It's there... It's in the upper left hand corner of this image:

http://www.synthdiy.com/files/2007/bossce-3.jpg

It's a 120k resistor.

You cant miss it... it's the one all the way at the top:

http://farm3.static.flickr.com/2769/4054427844_944d7871a3.jpg

Look at the schematic... look at your pedal... look at the schematic again.

BUY A MULTIMETER. I just did. They're pretty cool. And they allow you to measure resistance. You'd just have to find the one that's 120k.

And in case you didn't know... a resistor looks like this: https://cdn.instructables.com/FS0/R37K/GZACIV3W/FS0R37KGZACIV3W.MEDIUM.jpg

Also... WAYYYY too much backstory. (Just kiddin'... I love a good backstory. )

[Mark Hammer]

I own a CE-3.  Not a terrible pedal.  Its chief advantage is that it can also do vibrato, which many others cannot do.
However, because of the complexity  of having the dual outputs and dual modes,  a simple one-component mod to improve the output level might be tricky.

Removal of R18 will increase the gain of IC1 in effect mode.  But the problem is that it may have disproportionate effects on clean (via R15) and effect signal.

[yelemusic]

WOW, that was quick

Sorry for the long backstory (I guess I just like to tell stories )

So is it this resistor (the one I marked with a red arrow)?
klick here
It's got the wrong colour code though. The 120k is supposed to be brown red yellow gold AFAIK, which is the one I marked blue. That particular one should be directly connected to one leg of Q2, which is indeed the case. So I removed that one, but it didn't make a difference whatsoever, at least volume wise. So I put it back in.
Where did I take a wrong turn?

Blimey, I thought that's straight forward



@ Mark
I guess I'll just have to try. If it's not what I was hoping I can easily undo the mod.



Thanks guys!!!

[Mark Hammer]

When the pedal is in effect mode, Q2 essentially straps R18 in parallel with R19, which works out to a combined 34k feedback resistance, reducing the gain of that stage.  That's probably why some have recommended lifting R18.  In some respects, if one was interested in having the chorus effect be a little more prominent, R18 should really be placed  in parallel with R20, which would raise the overall gain of that stage in effect mode, for both wet and dry signal.  The trouble, of course, is that it  would mess up the complementary pre-emphasis/de-emphasis used for noise control.

And that's the "problem" with the pedal: all gain stages that carry both wet and dry (IC1 and IC2) are also used for pre-emphasis or de-emphasis, so you can't tinker with their gain without requiring change of other compnents to play along with the pre/de-emphasis.

I will note that I modded mine to use a smaller cap (33pf) in place of C25 to nail that zone which straddles flanging and chorus.  It gets a nice swirly slow Leslie tone.  A SPST toggle switches a 15pf cap in parallel with 33pf to revert back to stock delay range.

[yelemusic]

Oh, I see.
Not that I understood a word of what you said
I do appreciate your input though!

Man, I envy you guys who actually know what they're doing!
That's one thing I'd like to learn before I die!

I might look for another chorus pedal, because even though I don't understand what your saying, it still feels like you're saying to leave the damn thing alone.

[rainless]

WOW, that was quick

Sorry for the long backstory (I guess I just like to tell stories )

So is it this resistor (the one I marked with a red arrow)?
klick here

No you removed the wrong one. Look at the diagram again. The one you're looking for is to the right of that. R18 is always next to R19. The one you marked isn't next to anything.

Go ahead and desolder it. You can always solder it back on. Just desolder it... see how it sounds... see how you like it. If you don't... just solder it back.

It's that simple.

And hell... I just built my first pedal ever on TUESDAY. You don't have to do much to come to an understanding of how things work.

You just have to do *something*. So do something!

[yelemusic]

No you removed the wrong one. Look at the diagram again. The one you're looking for is to the right of that. R18 is always next to R19. The one you marked isn't next to anything.

Go ahead and desolder it. You can always solder it back on. Just desolder it... see how it sounds... see how you like it. If you don't... just solder it back.

It's that simple.

And hell... I just built my first pedal ever on TUESDAY. You don't have to do much to come to an understanding of how things work.

You just have to do *something*. So do something!

The one I desoldered had the correct value, and was connected with one leg to Q2, so I figured, that's the one. Desoldering didn't change a thing though, but I couldn't find any other resistor with the same value, even with a magnifying glass.

The one I marked sits next to a row of 4 capacitors, so I don't understand what you mean by saying isn't next to anything.

So, in that picture (with my two arrows) can you identify the resistor in question, preferably also with an arrow? Honestly I find it hard to read schematics and then find the corresponding parts on the board.
But thanks nevertheless!

[midiez1997]

Hi! Do you want solution to the problem?