Small Clone Chorus

[alparent]

I want to build the Small Clone Chorus on Tonepad's site.
Their is a mod to put a 4 pos switch to change cap values.

I have a 6 pos switch......what other 2 values could I add that would be useful?

I there more values that would be useful?  I can always put a 12 pos switch! 

[Mark Hammer]

Three positions and an on-off-on SPDT toggle is really all you need.  No reason to make it more complicated than it needs to be.  Besides, that switch is carrying clock signal; something you'd like to have as few wires floating around with as possible.  A 3-position toggle can make those wires mercifully short.  Once you get into 4 or more positions, the amount of wire multiplies.

I think, as well, that it pays not to go too far outside the boundaries of what the existing filtering anticipates.  150pf gets you a certain clock frequency, and the filtering is set up to give you maximum noise-free bandwidth with that clock frequency.  Increasing the capacitance reduces the clock frequency, and at a certain point starts to put it far enough below the filter rolloff that it starts to become audible as background whine/hiss.  While upping the clock frequency by reducing the cap value does not incur any such noise penalty, it starts to move you more in the direction of flanging, but without the benefits of variable resonance or a suitable LFO waveform.  

So, it may be a rather conservative opinion, but I think going too far in either direction with respect to cap value, starts to move you towards more cost than benefit.

What I've done on both clone and commercial Small Clones that I have is to run two wires from where the 150pf cap is supposed to go up to the outside lugs of a SPDT 3-position toggle.  I then solder a 150pf cap between common and one outside lug, and a 220pf cap between common and the other outside lug.  In the centre position, the two caps are in series, which gets us 89pf and moves the tone in the swirly slow Leslie range without sounding like a chorus.  Move the switch to one side to shunt the 220pf and you get an effective capacitance of 150pf; stock.  Move it the other way and the 150pf is now shunted out,giving you 220pf and more of a thicker Mike Stern kind of chorus.  YMMV, but personally, that's enough for me, and bloody easy for what it offers.

A nice balance between flexibility and ease of mod/construction with respect to a Small Clone is:
- a 3-position range toggle as per above
- variable sweep width (detailed at Tonepad)
- vibrato switch
- bass cut switch for the wet signal
- wet level/mix control

In tandem with the Rate control, that'll get you a pleasingly large palette of chorus sounds without taking up too much panel space.  Three pots, three toggles.

Tell you what.  I'll bring one in to work for you to try tomorrow, and let you be the judge!  

[KazooMan]

I mentioned in a reply to another thread that I had done the cap switching mod on the Small Clone Chorus using the very compact 6P2T rotary switch available from Small Bear.  Like Mark's suggestion, it boils down to just two wires leading to a small PCB that mounts the switch and caps.  I ended up with a range from 68 to 270 pf caps and I would have to say that both ends of the range are probably overkill.  Also with such small steps between caps the difference in the chorus is pretty subtle.  Still, it was fun to design the board and the small switch fits into a pedal very well.

See pics here:

http://www.diystompboxes.com/smfforum/index.php?topic=80575.msg666694#msg666694

[matt239]

Anybody know what the actual (or nominal) delay TIME is with the stock 150pF cap?

Or what it becomes with 89pF, or 220pF?

Or what it is in the CE-2?


- I'm guessing the time is a little longer in the Small Clone, vs. the CE-2.  ?