theremin virgin!

Posted: 1/10/2006 1:17:29 PM
hels

Joined: 12/26/2005

sorry to bother you again, but i have another problem...

my theremin (a kees)is now hardly making any noise at all... when i turn the gain and volume right up to max i can just about hear an output, but it is very weak and very high pitched...

what has gone wrong? :o(
Posted: 1/10/2006 3:39:12 PM
Charlie D

From: England

Joined: 2/28/2005

I have very little technical knowledge when it comes to the theremin, but I suspect that it would be difficult to diagnose your problem exactly without testing each piece of equipment individually.

You amplifier seems to be working . . . you say it's producing some sort of noise, so my first guess would be that the signal going *into* it has been somehow weakened. Try feeding a different signal into the amplifier to test it, and if it's OK then test they cable you're using with the theremin. Failing that, try using a different power supply. You can probably find all these things at your local electric/guitar music shop, and if you take your theremin along with you then you should be able to test everything for free. The staff will probably be very intrigued. :)

Otherwise - have you moved the instrument? Are you doing anything differently to when it was working?
Posted: 1/10/2006 3:43:03 PM
Jason

From: Sammamish, Washington

Joined: 2/13/2005

omhoge wrote:

[i]Maybe we should copy these last couple posts to a new thread in the Technique forum under "Vibrato and Tremolo".[/i]

Great suggestion! New thread started here (http://www.thereminworld.com/forum.asp?F=780&T=1638&cmd=p&p=1).
Posted: 1/10/2006 8:43:16 PM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

hels - Charlie asks some good questions. Has anything been moved or changed? Could anyone (like children) have played with the adjustment knob on the back?

I've found that when I have that problem the instrument cable is not fully inserted into the jack on the theremin or the amp. It's always best to check the simple stuff first.
Posted: 1/10/2006 9:18:14 PM
kkissinger

From: Kansas City, Mo.

Joined: 8/23/2005

Hels,

Jeff is absolutely correct: check the simple stuff first.

When troubleshooting your setup, you can check things methodically from the sound source to the speaker (and everything in between).

For starters, you want to be sure your Theremin is producing output. Unplug your Theremin from the amp and plug headphones into your Theremin -- the sound will likely be weak however if the Theremin plays normally then your Theremin is ok.

The next link in the signal chain is your patch cord that connects the Theremin's output to the input of your amp. The easiest way to check this is to substitute another patch cord and see if you get output from your amp. You can also jiggle the connectors to see if a wire has broken inside your patchcord. Make sure your amp is turned DOWN when checking this to avoid loud pops that could hurt your ears and/or damage your equipment.

If you still cannot get sound out of your amp, check any switches or control knobs on your amp. Go ahead and jiggle the switches a bit -- you could have a switch that has a dirty or intermittant contact.

If you suspect that your Theremin is not producing output -- before you start monkeying with the Theremin, try a different input source for your amp (a keyboard, a CD player's output -- any line-level signal will do). If your amp works with the alternate signal source, then we can suspect that the Theremin is not producing output.

For starters, check the power supply connection (jiggle it) and the on/off switch on your Theremin. (Make sure your amp volume is not turned up too loud while doing this.) Assuming you have removable antennae, remove and then reinsert them. Try turning the front panel controls to see if that clears up the problem.

After all else fails, then check the Theremin with headphones or a different amp -- if the Theremin still doesn't work, then you may need to adjust its pitch trimmer in the back.

The main thing is don't panic... there IS a logical explanation for the situation and, whatever it is, it CAN be fixed. So, take a deep breath and check all the obvious things first.

Keep us posted. Will be curious to know what the problem turns out to be.
Posted: 1/22/2006 12:48:52 PM
hels

Joined: 12/26/2005

my boyfriend has been emailing Kees and got a few ideas. he has now replaced one of the transistors and it's working better than it ever did before! I can easily find zero beat now and have a great range! just need some time to work on a performance piece!! i thought 'somewhere over the rainbow' would work nicely!
thanks for all your good advice!

h
Posted: 1/22/2006 3:33:30 PM
GordonC

From: Croxley Green, Hertfordshire, UK

Joined: 10/5/2005

Pleased to hear it's fixed.

You can find a link to an MP3 of Peter Pringle playing Somewhere Over The Rainbow on Theremin World's Repertoire (http://www.thereminworld.com/music.asp) page if you want something to play along with whilst practicing.

My theremin is about 250 miles away at the moment, but I'm guessing that the octave leap on "somewhere" will be a worthwhile challenge. :-)

(By the by - my favourite arrangement was on the Kenny Everett Show - just the introduction, but played on [i]Police Cars[/i]!)
Posted: 1/23/2006 9:03:14 AM
Jason

From: Sammamish, Washington

Joined: 2/13/2005

I'm curious - was the transistor replacement done to replace a defective part, or did he replace it with a different type of transistor? Just wondering if this is a mod other folks might want to make. Glad to know it's working better!!
Posted: 1/23/2006 11:13:31 AM
hels

Joined: 12/26/2005

the transistor was just a replacement...

thanks for the rainbow tip off. I'll let you know how i get on!

h :o)
Posted: 2/23/2006 9:19:34 PM
DiggyDog

From: Jax, FL

Joined: 2/14/2005

Haven't heard from you, Hels. Have you given up?

I hope not!

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