So, can CH-1 Super Chorus be modded to sound like...?

[DeeBug]

I got to wondering about this after reading the related threads currently on the board.  In particular, MH's statement that

Indeed, a shift in delay range of even a millisecond or two is often responsible for the audible differences and tonal preferences of one chorus vs another.

So then, could a Boss CH-1 Super Chorus be modded to sound pretty much like a CE-2 or a Small Clone by simply playing with that delay range cap?  Or is there too much else going on there in the circuit affecting that pedal's sound quality?

[Rob Strand]

There's not much difference between the two.  You should be able to take the CE-2 filters and transplant them into the CH-1 - which is just a matter of changing a few caps.

There's a slight  complication in that the CH-1 has a tone control.  If you use the CE-2 filter it will be like a CE-2 when the tone is on maximum.  I haven't looked at the CH1 -> CE2 conversion for a while but  even on max tone you might have to tweak a cap to get a good match with the filters.  If you want a CE2 match with the tone at midpoint then you will need more mods.

[Mark Hammer]

Rob's right.  It's delay range AND filters.

You will note that the vast majority of analog time-based effects tend to use as much filtering as is needed to yield noise-free performance and then back off.  They may err a little on the side of noise prevention OR bandwidth maximization, but they tend to stick with filtering based on what the anticipated clock frequency range will be.  So, if the chorus aims for a range of, say 5-15msec using a 1024-stage device, then the amount of lowpass filtering will be a bit more severe and with a lower rolloff than if it aimed for 2-10msec with the same device.

With that in mind, the safer strategy is often to mod the chorus to go shorter in delay range rather than longer.  By "safer", I mean something that would require no alteration of the filters and rolloff frequency.  If you mod it to do shorter delays, then the clock frequency moves upward such that the existing filters will do a fine job attenuating any clock noise that bleeds through.  If you increase the amount of delay, particularly if you increase it substantially, then the clock frequency may well be reduced to the point where the existing filtering and rolloff frequency does not remove enough of it.

That being said, small conservative changes in clock range created by adding caps, whether in series or parallel, can produce noticeable differences without placing the noise immunity of your pedal at great risk.  Big changes are nice but it doesn't have to be a big change to be the right change for you.

[DeeBug]

Wow!  Brilliant explanations guys, thanks! 

[domenico]

Hi I need an information about this pedal .
Do you have the digital or the analog one ? I have a digital boss ch-1 I would like to know the value of IC6.
Could you please help me ?
thanks
Domenico