YAEWSBM - Yet Another Etherwave Standard Bass Mod

Glad it worked out for you DarkShadows!  Thanks for posting your progress!

And thanks to Gianluca for his resistor suggestion!  I ended up with a 78k across the bypass jumper, enhancing the bass notes, while leaving the upper range alone.

Did a custom board for mine:

Top (installed)

Bottom

Schematic

It seems to still be doing something (smoother bass, no motorboating) with the bypass jumper bridged. I might even like it better this way, as it has less impact on the timbre and it still nulls out completely when you step away. But I'm not sure if that's to be expected, given my understanding of how this circuit works.

Also: I can't remember why I added a jumper for AMP IN to VCA OUT, but the answer must be somewhere in this thread.

Also: I have two more of these on my desk if anyone would like one. I'm not planning to further produce or sell them.

Did a custom board for mine:Top (installed)BottomSchematicI have to admit I was kind of expecting not to like this, but I do. I thought the theremin wouldn't null out completely when you step away, but it seems to work fine.Also: it seems to still be doing something (smoother bass, no motorboating) with the bypass jumper bridged. I might even like it better this way, as it has less impact on the timbre. But I'm not sure if that's to be expected, given my understanding of how this circuit works.Also: I can't remember why I added a jumper for AMP IN to VCA OUT, but the answer must be somewhere in this thread.Also: I have two more of these on my desk if anyone would like one. I'm not planning to further produce or sell them.

That is so cool! Yes, there is a slight difference with the bypass jumper installed than with the board removed.  I experimented with some capacitance at the point without the mod and got some smoother sounds and it's apparent that the board has some internal resistance/capacitance that is causing the effect.  The overall sound with the mod installed is much more to my liking than without, plus the added benefit of that useable lower octave or so.  I'm sure that's why Moog has done something similar to their new Etherwave model.

Edited my post - I thought it still nulled out completely when you step out of the field, but no, it has the same behavior as the ESPE01 where the pitch range starts to reverse. I do find that pretty annoying.

However, I think that with the bypass jumper bridged it still nulls as I'd expect? I'll have to put in a potentiometer.

Edited my post - I thought it still nulled out completely when you step out of the field, but no, it has the same behavior as the ESPE01 where the pitch range starts to reverse. I do find that pretty annoying.However, I think that with the bypass jumper bridged it still nulls as I'd expect? I'll have to put in a potentiometer.

Yes, it does start to reverse, because the two oscillators don't lock up.  It really doesn't cause a problem while playing, I find.  Instead of zero beat, I tune for a low note when my arm is retracted.  This method was suggested when discussing the mod.  My volume antenna is backwards from the norm, closer=louder, so that when I step away, it mutes.  I find this  more logical than closer=softer.  It may take a bit of getting used to with the original volume direction, but Katica Illenyi left her mod in and she seems to be fine with it.  I noticed she loops the audio cable over the volume antenna after performing, so that she can step away.  I encourage you to give the mod a chance.  I also can mute mine with a switch I added. 

Oh i'm definitely enjoying it so far, don't get me wrong!

Wow, super nice looking build Evan!

Wow, super nice looking build Evan!

Dewster, I figured you might chime in! By the way, I'm learning to play Debussy's Clair de Lune, after seeing Randy's and Gregoir's inspiring Youtube videos. Glad you're enjoying the mod, Evan. I'll never unplug mine!