Boss CH-1 Super Chorus - to mod or not to mod...

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Boss CH-1 Super Chorus - to mod or not to mod...

Postby biliousfrog » 18 Sep 2012, 18:41

I've got an original, analog CH-1 that I was hoping to exchange for stompbox tokens on ebay but they're not selling very well at the moment...I'm thinking about modding it a bit, perhaps get some use out of it, perhaps sell it anyway with the extra 'mod-factor'.

I'm just curious whether anyone has done any CH-1 mods and whether they're actually worth doing? I was thinking perhaps of changing C10 for a trim pot or side mounted pot to adjust the delay range from near-flange to crazy and maybe a vibrato switch...dunno?
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 26 Jul 2013, 17:45

I'm new to the forum and modifying guitar pedals. I want to modify my CH-1--not really much of an effect, as far as I'm concerned--and I had a question about the IC's for the mod. In the Wampler book on modifying this pedal, he doesn't mention changing the the IC's; however, the Monte Allums site has two IC's switched out in their kit. Does changing these IC's matter? If so, which ones would I change in the circuit and to which values? Thanks!

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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby square wave » 26 Jul 2013, 18:32

It'd be easier to answer the question with some context. What IC's are being removed, and what are they being replaced with? Do you have a schematic for us to reference?
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 26 Jul 2013, 19:44

Thanks for the response. The new IC's in the Monte Allum mod are labeled "RC4558P" and "OPA2134PA." I'm not sure of the values they're replacing, but looking at the board of the CH-1, it might be those labeled "MN3101" and "MN3007." The mod claims to clean up the circuit. Again, the Wampler mod doesn't include changing the IC's. I guess my question is two-fold: 1) if it matters to change these IC's, what should I change each one to?

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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 26 Jul 2013, 19:55

Looking more closely at the pedal's PCB and the Monte Allums mod, i appears the Monte Allums mod uses an 8-pin in-line socket device to hold two 8-pin (4 in parallel) IC's. It looks like a small PCD. It's called a "Dual Stack Chip Adapter." I'm not sure what it does. I can't get my hands on the instructions for the Monte Allums mod.
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby Fender3D » 26 Jul 2013, 20:01

Please, don't hurt that poor CH1....

You clearly don't know how to do a mod.
Read datasheets to know what chips you're facing, first
Then try figure out HOW the pedal works, following a schematic.
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 26 Jul 2013, 20:33

That''s not very nice: Actually, I've done several mods, each one successfully. I just had some questions. I guess this is why people get called trolls.
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 26 Jul 2013, 20:44

mrsmith77 wrote:Thanks for the response. The new IC's in the Monte Allum mod are labeled "RC4558P" and "OPA2134PA." I'm not sure of the values they're replacing, but looking at the board of the CH-1, it might be those labeled "MN3101" and "MN3007." The mod claims to clean up the circuit. Again, the Wampler mod doesn't include changing the IC's. I guess my question is two-fold: 1) if it matters to change these IC's, what should I change each one to?

Mike


My original question still stands.
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby Fender3D » 26 Jul 2013, 20:59

This is not a matter of trolling, rather is a matter of killing chips !

You're gonna damage your pedal if you swap chips this way.
The fact they're all black plastic and 8 pins, doesn't mean you can swap them without knowing which pin does what...

Then, you won't learn anything if you don't compare the stock schematic with what you're gonna do.
This means you ought to know how chips (and other parts) work.

The very first question about ANY pedal mod should be:
"my pedal xxx does this, I would like her to do that", story tells a lot of people soldering parts randomly and "by numbers" then sit down with what they've achieved, then call this a mod....
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 26 Jul 2013, 21:47

I appreciate your concern for my pedals, but it's not really that big a deal. As a beginner, which I clearly called myself, I had a few questions about which IC's might be swapped out to improve the sound of a CH-1 pedal. I think that means I was not looking to swap chips on a whim, rather looking for specific instructions on which ones to swap and to which values. But, again, I appreciate your concern for my pedal; however, if it breaks, I'll fix it.
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby Fender3D » 27 Jul 2013, 00:46

Hey Mike,

I didn't mean to be rude...
But when you said:
mrsmith77 wrote:... "RC4558P" and "OPA2134PA." ... it might be those labeled "MN3101" and "MN3007."

I guessed your confusion...

Improve the sound is a little vague:

if you need less hiss then swapping a mere 4558 with an OPA (or 5532, at least) is a good idea,
this "mod" won't change the sound at all, hiss aside, since op-amps are simple buffers or mixers, here.

if you need a deeper chorus, you'll have to mess with clock capacitor (C10 on this http://www.freeinfosociety.com/electronics/schemview.php?id=2290 schematic)

the same if you're looking for a more flangey sound.
This "mod" will change the sound a lot, you'll have to evaluate if this is an improvement or what...

A switch on "out B" ring lug and GND will give you a preview of the "vibrato mod"

You may also trim LPFs at your taste for a more open or close sound.

All of this will be easier if you can read a schematic, of course...
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Re: Boss CH-1 Super Chorus - to mod or not to mod...

Postby mrsmith77 » 27 Jul 2013, 02:59

Thanks, that's exactly what I was looking for! I greatly appreciate your help and will let you know how it goes.

And I'm learning to read schematics; I'll have it shortly.

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