I don't get the right values out from reg 1! what could be wrong?
silicon chip/jaycar kit
Posted: 5/17/2009 10:16:17 AM
The most important problem is that the volume antenna is very close to the pitch antenna. So your left hand movements may influence pitch also.
Simple check:
a) Connect the theremin to an amplifier in order to get it better grounded.
b) Hold your right hand near the pitch antenna in order to hear a tone around one octave higher than middle C.
c) Now move your left hand above the volume plate within a 0 to 10 cm range. If that alters pitch by about a halftone, it's normal. If that makes much more, turn the slug of T1 a half turn clockwise and then retune T2 until you have anew the correct pitch behavior and range.
In neither case touch T3, T4 and VR2 please!
Simple check:
a) Connect the theremin to an amplifier in order to get it better grounded.
b) Hold your right hand near the pitch antenna in order to hear a tone around one octave higher than middle C.
c) Now move your left hand above the volume plate within a 0 to 10 cm range. If that alters pitch by about a halftone, it's normal. If that makes much more, turn the slug of T1 a half turn clockwise and then retune T2 until you have anew the correct pitch behavior and range.
In neither case touch T3, T4 and VR2 please!
Posted: 5/17/2009 10:44:26 AM
That's a question of fine tuning by adding or subtracting some millimeters from or to the pitch antenna length. If you hear a relatively high tone when your hand is away which goes still higher when you move towards the antenna, capacitance is too big an you have to shorten the antenna slightly. If the tone goes first lower before raising when approaching the antenna, capactiance is too small and you will have to add a few millimeters.
The maximum range is only reached when
a) the theremin is properly grounded.
b) the theremin is far away from metallic parts.
c) your body is at at least a 60cm distance from the theremin.
But please do not forget one thing: The SC theremin in this version is a cheap and simple one. So don't expect it to behave like a professional instrument. If you will be more familiar with it, we may add some modifications in order to improve it.
The maximum range is only reached when
a) the theremin is properly grounded.
b) the theremin is far away from metallic parts.
c) your body is at at least a 60cm distance from the theremin.
But please do not forget one thing: The SC theremin in this version is a cheap and simple one. So don't expect it to behave like a professional instrument. If you will be more familiar with it, we may add some modifications in order to improve it.
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