Switchable Speed/Depth chorus...can this be done?

[skiraly017]

I have a Small Clone clone. I want to make it a two channel pedal and be able to switch between two different settings (Chorus 1 and Chorus 2), each setting having separate Speed and Depth. Can this be done with -

One circuit board.
One 3PDT for on/off.
One 3PDT for channel select.

The knob layout is -
Speed 1 - Depth 1
Speed 2 - Depth 2

I have been told this can be done. I've been told it can't be done. I've been told I need a 4PDT switch for the channel select...any help would be greatly appreciated. Thanks.

[nelson]

It is possible to do the Ch select with 1 3PDT.

Use a SPDT to select the speed pot, one lug of the speed pot will always be connected.

Use the remaining DPDT to select the depth pot. They can share a ground connection.

All adds up to a 3PDT

you wouldnt be able to have an LED though, to indicate which settings are selected.

[skiraly017]

So can I safely assume that Analogman is using a 4PDT switch in his Bi-Chorus since he is using a LED for the channel indicator?

[Mark Hammer]

You know, if you were willing to have a 2nd LFO, you would only need a SPDT toggle to switch between two sets of Speed and Depth controls.

[Pushtone]

I want to build a dual chorus (or a chorus with dual controls) like
the ones discussed in this very helpful thread.

It's interesting that analogman has posted a guts pic of the Bi-Chorus
and it does have two 3PDT switches in there. Not a 4 pole as ventured above.

http://www.analogman.com/clone.htm about halfway down.

Then I count the number of ICs in his Bi-Chorus. Humm only four, so wheres the second LFO?
Perhaps he's using the 3PDT to switch pots like Nelson said but with the flashing LEDs
there must be more going on that I rather not get into right now.

I think I will attempt this Mark's way with a second LFO board piggybacked on top of the main board.
Your right Mark. When I looked close at the schem it's painfully obvious where a SPDT would go between two LFOs.
This way I can use a DPDT switch and still have two LEDs. I won't bother making them flash with the rate.

I think I have separated the right parts for the 2nd LFO on the Tonepad pcb.
The LFO section starts before the 39k resistor. This should work.


This should be the correct traces for a transfer of LFO #2 (after the unused pads are removed).




Question?

Do I need another 220uF filter cap on the second LFO board if I'm taping the power
from the main board at the unused pad the red arrow is pointing to?

[Pushtone]

Hey skiraly017,

How did you end up working this out if I may ask?

[Pushtone]

I couldn't wait for a response, I'm too excited.

I double checked the traces, created a few pads, made it a little smaller,
and etched a second LFO daughter-board.
I'll use nylon bolts and nuts as standoffs to set the board hieght over the main board.
I am also attempting to line up the power and ground "link" pads between boards so I can use stiff square header pins
as conductors/standoffs.

Oh my I hope this works.



Would very much like to know if the 220uF cap is needed on the second board.
I'll try leaving it out. I can always add it later.

[Pushtone]

Bump...

Would someone please take a look at the traces for the second LFO board.

Did I get all the ones needed for a complete second LFO?

Thanks in advance.

[Pushtone]

Is this the end of Zombie Shakespeare?

Will no one comment on the traces for a second LFO?

I'm going to start populating it now.
I guess I'll find out if I got it right that way.

How do I test the second LFO?
Will there be a pulse I can meter?
If so, where should I probe the LFO to see if it has a heart beat?

[audioguy]

Cool... I might have to give it a go!

[audioguy]

So where does the other end of the 39k go?

[skiraly017]

I actually managed to do it off a second 3PDT stomp and the single board. I have it drawn out somewhere and it works very well.

[Pushtone]

So where does the other end of the 39k go?

I found out that it was a mistake to tap the LFO at the 39k. Caused an ultra loud pop when switched.

In the build report I include a wiring diagram that works. Follow that.


You should read this post too. Its where I reported the problem with switching before the 39k.
http://www.diystompboxes.com/smfforum/index.php?topic=51276.0

Once I figured it out it was all to clear were to put the switch.

And for those finding this thread in the future, here is the finished build report link.
http://www.diystompboxes.com/smfforum/index.php?topic=52149.0