Thierry E-Pro Mod - Part 3

Posted: 9/24/2009 12:25:54 AM

From: Kansas City, Mo.

Joined: 8/23/2005

Well, I installed the mod on my Epro.

All I can say is "WOW!!!" -- Thierry's mod gives the Etherwave Pro a level of control and expressiveness that it didn't have before. Bob Moog must be in heaven smiling ear-to-ear.

[b]The Installation[/b]

I have an early theremin (0063) and it has a mod "c" volume board. Thus all I had to do was replace R67 with Thiery's socket. The entire operation took less than 30 minutes. I spent another 30 minutes trying the different jumper positions and settled on position '3'. I had to adjust the coil (accessable from the hole in the side of the Epro) to find the best setting.

[b]What the mod does[/b]

The stock Epro has a definate "pluck" point above the volume loop. This point is the distance from the volume loop where the sound jumps from "off" to "on". The coil next to the volume loop adjusts the position of the "pluck".

Thiery's mod has the effect of filling in the gap from the loop to the pluck point. When I first installed the mod there still was a definate "bump" in the volume curve at the position of the pluck. I had to adjust the coil about 1/8 of a turn to get a smooth transition without a volume bump at the pluck point. Note that some settings of this coil can produce some distortion and one must check the response with the volume knob both left and right.

Another effect is that the volume knob is very effective now. The leftmost position gives a very gradual volume increase whereas the rightmost setting is almost full-on/full-off.

[b]The rotary switch option[/b]

I just got the mod board with jumpers rather than a rotary switch. I have adjusted the coil such that the volume knob gives me a huge range from very gradual to extremely-snappy. The volume knob, in fact, is much more effective and useful now. Thus, I don't have a need for the rotary switch option -- not to mention that to change the mod's setting would (at least for me) necessitate and adjustment to the coil.

[b]Initial concerns[/b]

One of my concerns was that some of my looping works would be difficult with a less-snappy volume response. However, the volume is just as responsive -- the difference is that the gap between the loop and the "pluck" is filled-in. I did not have to change my technique to accomodate the modification -- much to my pleasant surprise.

[b]Practice session[/b]

I am in the throes of practice for a theremin performance this coming Saturday. I was a little hesitant to put in a mod so close to a performance date however I could see that it could be easily reversed if need be. Well, needless to say, I won't be reversing it!

To play works such as "The Sad Little Ghost" was really wonderful with the new expressiveness. Also, I can fade in notes gradually which gives me a better chance to tune the notes during the attack.

Also, this mod increases the dynamic range of the theremin. Now I can play works such as "Mummies and Unholy Ghosts" and "Last Leaf of Autumn" without the accompaniament drowning out the theremin in the loud passages. In last leaf, there is a sustained middle 'C' that used to get buried in the mix and now I have enough extra "umph" to bring the note out.

I also played through the Bach-Gounod "Ave Maria" and the increased smoothness and dynamic range allows me to produce a much more satisfying performance.

Others have said this and I must agree: if you own an Epro this mod is a must-have. It sacrifices nothing (if you want a snappy response you still can have it) and gains you a huge amount of dynamic range and control.

A big THANK YOU to Thiery for designing this mod and making it easy to install.

[i]-- Kevin[/i]
Posted: 9/24/2009 3:32:00 AM

From: Colmar, France

Joined: 12/31/2007

Kevin, you're welcome!

Thanks to different time zones, your positive feedback was the first thing I saw this morning. So you made my day and I could forget the pains in my broken leg for a short time.
Posted: 9/29/2009 2:58:50 AM
Dave H

From: Sedona AZ

Joined: 7/12/2009

I have Etherwave Pro #0186 anything unusual with this unit in trying to add a mod board?
Posted: 9/29/2009 4:32:27 AM

From: Colmar, France

Joined: 12/31/2007

Normally no problem. The only thing is that the serial number doesn't allow to know which volume board revision is built in. If you want to double-check take a high-res picture of your volume board and send it to theremin(at)tfrenkel(dot)com

As soon as I had a look on it, I'll be able to tell you exactly.

In general, the EPVM1345 module works with every board revision, it also works in the left-handed version of the EPro. The only cases where problems could occur is when there are already other individual mods done by moog, except their volume mod. Actually I'm awaiting pics from someone who has already an additional board for reversing the volume loop behavior and from someone whose volume board was individually modified by moog in order to repair a ghost tone problem. As soon as I have more information about these rare special cases I'll post here.
Posted: 9/29/2009 5:58:39 PM
Dave H

From: Sedona AZ

Joined: 7/12/2009

Photos of front of volume board and rear of volume board
were sent to you.

I send a second set of pictures as the first set was lowered in quality after sending as email file attachment. (I sent them to me as well and did a quick check.)

Second set was sent as Zip file and they kept their high quality.

Dave H
Posted: 9/29/2009 6:24:17 PM

From: Colmar, France

Joined: 12/31/2007


you've got new mail ;-)

Since threads are closed automatically after 26 posts lets continue here (

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