Echo base mods

[Jmsteele187]

Hey guys, I have a question that I hope I can get some help on.  I'm planning on making the echo base delay and have read through some threads and documents on the build.  One of the mods is a wave shape control, using a pot.  I'm wondering how I can just make it switchable from one extreme (chorus) to the other (vibe).  I've seen it done on a few demo videos, so I know it can be done.  Any advice?  Thanks in advance.

[Phoenix]

Hi Jimmie,

I'm not familiar with the Echo Base circuit myself, but I can tell you that the difference between a chorus and a vibrato is that a chorus is a modulated delay that is mixed with the dry signal, but a vibrato is just a modulated delay, without being mixed with the dry signal, so you should be able to add a mix control on the dry path to get the two extremes.
Hope that helps.

[Jmsteele187]

Maybe this will help clarify things.  I'm using a board I got from musicpcb.com, and there is a document file on their site with a list of mods w/ instructions.  However, the file only has instructions to do this mod with a pot.  I'll include a link to the page, the mods I speak of is at the very bottom.  http://static1.squarespace.com/static/54696a3ee4b05a85cbfe56e5/t/5469759be4b05145d3fd695e/1416197531945/Echo-Base-build-PDF-updated-051810.pdf

[Phoenix]

Page 6 of the document you linked describes how to achieve what you want with a switch.

[Jmsteele187]

Not that mod, the one on page 10.

[Phoenix]

Ok, then you can substitute the 25k pot for a 25k resistor, and use a SPDT switch to switch the end of the 240k resistor between either end of the 25k resistor.

[Jmsteele187]

Okay, thanks!  I think this makes sense to me lol.  I'll mess around with it this weekend, and see what I can make happen.