YAEWSBM - Yet Another Etherwave Standard Bass Mod

dew,

The simplicity of your modification is what led me to the classic Clara sound I was after, for about $30. This mixer method can be applied to solid state or vacuum tube. At about the halfway point in the sample below I Switch on Clara for an OMG moment, it was magical. 

What makes the theremin special is how something very beautiful can come from a simple electronic circuit using human influence, not a cheap toy sine wave whistle. Below is a slight modification of an EtherWave Standard similar to the Bass mod. I gave away the small PCB to do this at no cost and almost no one was interested. Some want to only go low when my circuit goes beautifully high and rumbles low. My expectation for a theremin musical sound must be different than most, I guess.
 
http://www.oldtemecula.com/theremin/ews-buffer-exciter/sounds/ews-clara-off-on.wav

Christopher

You mention sub 1 Hz as useful, we have earthquakes in so cal in that range, had one 5/8/18 not enjoyable. 4.5 mag

Having more range on the EW Standard, I wonder, would it make sense to add a range switch like the EW pro has, to not cram so many octaves in an arm's length of control?
What would need to be changed in the pitch oscillator(s) to get only an about 2 octaves change (which I guess is what the 6 octave EW pro does, as it has 3 ranges from what I found?), and what would you switch to get different ranges? I guess one could tap the capacitor of the LC circuit, I wonder whether running wires from that to a switch on the metal front panel would have uninvited consequences.

"Having more range on the EW Standard, I wonder, would it make sense to add a range switch like the EW pro has, to not cram so many octaves in an arm's length of control?" - tinkeringdude

Due to what I've dubbed "the invariant" a conventional heterodyning Theremin is pretty much stuck with a constant sensitivity if it is nulled to have a maximally linear mid-field.  There's nothing much that you can do to change this in the analog domain.

"What would need to be changed in the pitch oscillator(s) to get only an about 2 octaves change (which I guess is what the 6 octave EW pro does, as it has 3 ranges from what I found?), and what would you switch to get different ranges?"

I believe identical digital dividers on both the variable and fixed oscillators, pre-mixer, will give you octave selection.

If anyone is interested, here is how I installed a YAEWSBM in a Moog Etherwave Standard.  I wanted to be able to remove or replace it without any soldering.

1. I installed 2 pin male headers at the C2 and C6 locations

2. I removed the reverse polarity protection diode, installed an 8 pin male header strip on the expansion port, then reinstalled the diode on the bottom of the board (not shown)

3. I installed an 8 pin female header on the edge of a small piece of pad per hole protoboard, then built up the YAEWSBM.

4. The YAEWSBM is plugged in and connected to the C2 and C6 headers with short Dupont jumpers. (This is the mechanical weak point, so I may use a different type of connection.)

5. To reverse the mod, unplug the YAEWSBM and put jumper blocks on the C2 and C6 headers.

Hi Dewster,
I tried your YAEWSBM v2.0 on my etherwawe and I noticed a nice improvement in the bass (frightening) but alas unfortunately I noticed that finding the correct notes is now more difficult than before as if it is out of tune, even after having correctly tuned the all; it is practically more difficult to keep a given note over time without getting out of tune.
Have you ever noticed this problem?

Do you have a late model EtherWave Standard? Start with this Link and work your way up the posts.

If all else fails remove it and solder a 47pf capacitor across D4, 100pf will be like you have now but for may taste it is too smooth and ruins the upper voice. This approach also makes the 1/4" jack output less hot for guitar amps.

My Clara Voice as heard above is an add-on with a three wire connection in the EWS box with no board removal or internal board modifications. This is a DIY for people in the States as I mail the PCB and other stuff at no cost.

Christopher   

Hi Dewster,I tried your YAEWSBM v2.0 on my etherwawe and I noticed a nice improvement in the bass (frightening) but alas unfortunately I noticed that finding the correct notes is now more difficult than before as if it is out of tune, even after having correctly tuned the all; it is practically more difficult to keep a given note over time without getting out of tune.Have you ever noticed this problem?

Did you remove the main board to install the YAEWSBM?  You may have changed the orientation of the wire between the main board and the pitch antenna, or loosened the screw connecting it to the antenna.  Either one can mess up the pitch range/linearity.

I don't see how the YAEWSBM could have any effect on oscillator drift.

Also I don't think the thread linked by oldtemecula is relevant.

Funny how this thread disappeared and now it is back. Could un-earth grounded spiritual forces be at work?

edavid nice photos! No socket for the LM13700 is disappointing, wonder why Moog thought this was better.

Christopher

"If anyone is interested, here is how I installed a YAEWSBM in a Moog Etherwave Standard."  - edavid

Very nice work, and great method to totally back it out.

"I tried your YAEWSBM v2.0 on my etherwawe and I noticed a nice improvement in the bass (frightening) but alas unfortunately I noticed that finding the correct notes is now more difficult than before as if it is out of tune, even after having correctly tuned the all; it is practically more difficult to keep a given note over time without getting out of tune.  Have you ever noticed this problem?" - Gianluca

Can't say that I have.  Did you try the defeat jumper?  Did you try backing it out to see if the EW was not damaged in some way by the install?  It seems there are variations on the EW out there that don't like the ESPE01 module, I hope Thierry can tell us why that is.

(First time I'm seeing these posts for some reason.)

Hello everyone, as in the photo, adding the mood is very simple, just a weld on C6.

The changes made to install the mood were made a long time before so as not to disassemble the board.