It's not working correctly!!!

Posted: 12/5/2008 10:52:18 PM
glue

Joined: 3/21/2008

So, I recently returned to my theremin after a long distraction caused by work, and I noticed that it wasn't functioning correctly! What I mean is that when my hand is at the far left of my etherwave theremins box, and the pitch knob is at it's normal position (all the way left) I cannot produce a pitch. It's in the same position it has always been in and nothing has been added to my room. When the knob is in this position, I only start to get a pitch about 3 or 4 inches away from the antenna. Why could this be/how do I fix it??
Posted: 12/6/2008 7:34:06 AM
Thereminstrel

From: UK

Joined: 4/15/2008

Hello "glue".
I'm probably not the right person to answer this - however, stick around, someone more technically-minded will advise you sooner or later.
Meanwhile, I'll just comment on one thing you mention: "the pitch knob is at its normal position (all the way left)"
I wouldn't call this a "normal position"; the optimum position for the pitch knob varies all the time, which is why it's adjusted almost every time the thereminist gets ready to play. Usually, turning to the left (anti-clockwise) will widen the field of notes; turning to the right (clockwise) will narrow the note field. Although there's no "normal" position, it's likely that, if you tune to an "octave-jump" or so that you stand in the zero beat, the knob would point somewhere between 12 o'clock and 3 o'clock, although this can vary.
If, when you have the knob all the way left, you have a very narrow note field, that seems odd; I would've thought it would be at its narrowest all the way to the right. You may need to do some internal tweaking, and I'm not the right one to advise in that case.
Sorry I can't be more helpful.
Posted: 12/6/2008 8:53:49 AM
glue

Joined: 3/21/2008

Yeah. I was thinking that I sounded like someone who didn't know how to play the theremin when I said that. Why I said the "normal" position was just to emphasize that nothing had changed and that even when the pitch knob was there I usually got a sound.
Posted: 12/6/2008 11:03:25 AM
Thereminstrel

From: UK

Joined: 4/15/2008

Okay! My apologies for explaining the obvious. I thought it was worth mentioning ... just in case. It's so easy to start out with things not quite right and them get so used to them it's impossible to play any other way. For example, the person I bought my theremin off had always kept the pitch dial turned almost fully clockwise and played the outer field (beyond the zero-beat where the notes are in reverse order!) I can't imagine how he managed it - but I guess that once he'd got used to playing back-to-front it was hard to change.

Anyway, if on your theremin the note field is very narrow when the pitch dial is fully anticlockwise, then I'd say there IS something amiss. But it should be fixable! It's often quieter here at weekends than midweek, but, fear not, someone will have the appropriate advice for you sooner or later!
Posted: 12/6/2008 1:05:05 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

It seems that your Etherwave has to be re-tuned internally.

The positive pitch field (where pitch goes up when you move your hand towards the rod) should be about 45 +/- 10cm (18 +/- 4" for Anglo-Saxons) with the pitch knob in its centre position (twelve o'clock) and even increase when turning it counterclockwise (leftwards).

If you do not have the equipment yourself, you should find someone who owns a frequency counter or an oscilloscope and follow the procedure on pages 6 and 7 of this service manual (http://www.moogmusic.com/manuals/HotRodEtherwav.pdf)

After each step, you should re-close the cover (if you do not want to drill holes in it in order to reach the slugs) because it completely changes the behaviour of the instrument. This makes the procedure quite long-winded and annoying, especially if you want to tune it for a bigger (5+ octaves) range but it is worth the pain.

Some tell that it would be enough to place the cover the other way round on the circuit, that helps but is insufficient. The pitch osc. goes still down by about 700Hz when putting the cover correctly...
Posted: 12/6/2008 3:55:09 PM
GordonC

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

Hi Glue.

The manual is scary! There's a simpler procedure in the last posting on this thread:

http://www.thereminworld.com/forum.asp?cmd=p&T=1895&F=1&p=2

which will sort out the majority of problems well enough, and doesn't require special equipment other than the red twiddly stick that came with your etherwave.
Posted: 12/29/2008 9:19:34 AM
glue

Joined: 3/21/2008

I think I messed up really terribly. So I finally got around to doing this, and was looking and the simpler tuning method first, but I didn't notice that it said "plastic" screwdriver. I just used a metal hex-bit. And I realized that something was wrong with this because when I put it into the slug, the pitch changed from when the hex-bit was out to nothing. Then I looked at the official manual, and I saw that it said that the "red hex-bit" that came with the kit is now "required". And that was plastic. I think that by using a metal hex-bit I really did something bad. Also, on a side note, it looks like in the L6 slug, the edge around the slug, not the square block around it, has ... melted or deformed somehow, and it's not because I stripped it out or anything. HELP!!!
Posted: 12/29/2008 1:28:50 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

These slugs are made from a kind of graphite material which tends to break when manipulated with metal tools...

In your situation I would stop further experiments and have someone competent looking after your Etherwave. Where are you located?
Posted: 12/29/2008 9:10:53 PM
glue

Joined: 3/21/2008

New York City.
Oh poop.
Posted: 12/30/2008 3:05:03 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

OK.

Since I think it would be too complicated to send it to France in order to get it verified and fixed by me, you could find someone in your area. It hasn't to be a theremin specialist. A normal radio/tv service technician should be able to do it. I'm ready to tell him what to do by MSN audio/video chat or by phone.

But for a first diagnostic you may also take a detailed picture of L6 and send it by email to theremin(at)tfrenkel(dot)com. Tell me also your MSN address and we could do some real time chat in order to see the real amount of damage.

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