ESPE01 installation success!

Posted: 3/13/2012 5:57:00 AM

From: Hillsborough, NC (USA)

Joined: 2/13/2005

I finally installed an ESPE01 into an old Big Briar signature Etherwave Standard tonight. 

It works! 

I have to say - it would definitely have helped to have a second pair of hands for this installation, but I managed to install it by myself.  All those years of practicing with chopsticks came in handy while I was holding a pair of tweezers and solder wire in one hand with my iron in the other.

The low-end bass sounds superb!  I seem to have lost a little of the high-end pitch range though, but I suspect this is just a matter of re-tuning the pitch circuit to run a little higher.  Thierry, Fred, RS or others - I'd appreciate any tips you could share on tuning the Etherwave to have a wider range.

A big thanks to Thierry for producing this awesome mod, to Wilco for selling it and providing a photo showing me how to install it in this ancient version of the Etherwave, and MollyDad for typing up the installation instructions so I could just read them off as I worked. (see the Mods page in the Tech & DIY section - I apparently have a bug in the site that prevents creating links to other pages of the site from the forums)

I argued with myself for a long time (too long) about whether or not to hack up my old EW.  Eventually, I decided Bob would have wanted it.  He designed the EW to be hacked, providing break-outs for the audio & aux signals as well as power and ground.  I'm sure he would have appreciated Thierry's engineering too.

Consider me a very happy (modified) Etherwave owner!

Posted: 3/13/2012 12:57:56 PM

From: Northern NJ, USA

Joined: 2/17/2012

"All those years of practicing with chopsticks..."

Ha ha!  Congrats Jason, glad the mod went well for you!  A couple of days ago I modded my EWS (with my own mixer buffer design) and the low end is now 100% better.  I can see reasons for the original circuit: oscillator locking at the low end keeps it from making noise when you back away from it, and the low end is perhaps "stringier" sounding.  But it hurts low end range, linearity, and I would argue tone.

I also was reluctant to mod mine, but the existence of Thierry's excellent mod (and Thomas Grillo's excellent video of it in action: gave me courage.

Posted: 3/13/2012 4:27:04 PM

From: Nashville, TN, USA

Joined: 12/22/2011

Hey Jason,

I'm glad you got around to doing the mod....I had to fiddle around with the tuning a couple of times after my friend Allen and I added the ESPE01 to my EW plus...I finally got the tuning set so that the pitch knob is between 12 and 2 o'clock for my preferred field setting. I like the field just a little bit tight so that I can get a whole octave by opening my hand from closed to open position (I play right handed with my palm down and my little finger nearest the pitch antenna).  It seemed to me that the shape of the field became more like an egg after the mod, so that I had to be more cognizant of trying to keep my right hand at about half the height of the pitch antenna in order to maximize linearity.  I also noticed the effect that dewster mentioned about the instrument no longer silencing once I reach zero beat and try to walk away. I actually see some kind of secondary field which is reversed..i.e. the further my right hand gets from the pitch antenna once it passes zero beat, the higher the pitch in the secondary field becomes..

This being said, I'm still very happy with the improved tone and range of my Etherwave.  I wouldn't go back to the way it was before.  Period.  (thanks again, Thierry, Wilco)... I believe if Bob Moog were still alive, he would insist on this mod being incorporated into his stock instruments...

Posted: 3/13/2012 4:54:04 PM

From: Northern NJ, USA

Joined: 2/17/2012

"I actually see some kind of secondary field which is reversed..i.e. the further my right hand gets from the pitch antenna once it passes zero beat, the higher the pitch in the secondary field becomes.."

During normal play, the variable oscillator is lower in frequency than the fixed oscillator.  Once you get far enough away to get past zero beat the variable oscillator goes above that of the fixed and you hear a rising tone the farther you move from the pitch antenna.  Low frequency oscillator locking (pre-fix) prevents this to some degree but it has other issues - the locking cons outweigh the pros IMO.

I have a jumper on mine that allows me to easily go back to the pre-mod state (not entirely but close enough - I don't believe it messes with the tuning or calibration when you switch but I need to check that).

Posted: 3/13/2012 5:09:16 PM

From: Colmar, France

Joined: 12/31/2007

Hi Jason,

thank you for your kind words.

Extending the pitch range towards the top can be done on all Etherwaves (somewhat more on the newer ones and somewhat less on the older ones) but there remains always a risk to destabilize or even to kill the variable pitch oscillator due to too high resonance currents through the linearization coils. So it has to be done with "finesse" (don't know an English word for that) and best with the help of a frequency counter and an oscilloscope or with much experience.

Although I could generate plenty of new repair clients who'd need their variable oscillator fixed by publishing here a tutorial about how to improve the pitch range and linearity, I'm not a serial killer. But I'm ready to help with my experience in individual Skype or Facetime sessions. I need to hear what happens exactly if there are already neither frequency counter nor oscilloscope.

People who are interested in this service may contact me by email service(at)theremin(dot)tf

Please understand that this will be working time for me and that I'll not refuse personal donations via PayPal in case of success (which is almost guaranteed).

Posted: 3/21/2012 7:43:37 PM
Wilco Botermans

From: Netherlands

Joined: 5/20/2011

Hi Jason,

Did you manage to tune it up a bit higher?



Posted: 3/22/2012 5:08:48 AM

From: Hillsborough, NC (USA)

Joined: 2/13/2005

Hi Wilco!  Yep - I was able to tune it without too much trouble.  Thanks for sending me the helpful tips.  I followed the hotrodding guide and now have a nice 5 1/2 octave range to play with.

I absolutely love the tone in the bass ranges, and the "cello" tuning tips were also really helpful.  I play it through my PC using Cakewalk Sonar X1 to apply various effects - my favorite being a tube amp simulator.  That adds a slight bit of latency to my playing, but not enough that I'm too concerned about it.  I've tried with both "wet" and "dry" signals (direct to an amp without the PC in the loop) and the bass tone sounds great in both.

Excellent work guys!


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