Thanks for the explaination. I think I understand. I have had good luck so far with theremins and coil winding, but honestly I am totally in the dark when it comes to the mysteries of inductance and frequency oscillation. nearly every build has at least afew momentents of complete frustration from dealing with what seems to be supernatural forces.
that being said... I plan on following the keppinger coil instructions as closely as possible, so Q shouldn't be an issue( i hope.)
I have found a few more thing that need clarification though:
* The coil form diameter for the large volume and pitch coils (L2 and L6) is different on the two parts list Ive found. Jeff Sparks parts list (http://www.thereminworld.com/files/projects/mktheremin/mkcomponents.pdf) has the form diameter at 3.30" while Phillip Neidlinger's excel parts spread sheet (http://www.neidlinger.us/keppinger.htm) lists a 3.1" diameter form. Both list the same gauge wire and # of windings??
So I guessing that the ocillators are a little forgiving and the inductance doesnt need to be dead on. ?
* Phil's list also says L1 has a double wrap with layers for craft paper soaked in shellac between windings. the other only mentions one winding, tapped at 50 turns. ? any thoughts?
Any suggestions of where to find phenolic coil forms that size. I was just planning on using my stock coil form material :heavy cardboard tubes covered with shellac or interlux wood sealer (a clear oil based sealer used to "prime" wood before applying varnish). They have about a 3.25-3.27" diameter. closer to the size stated on the jsparks list.
Also what size chassis did mr keppinger use?.. and beside phils page are there any other photos or diagrams of the layout? I want to stick with an already winning formula. Thanks for the help.
that being said... I plan on following the keppinger coil instructions as closely as possible, so Q shouldn't be an issue( i hope.)
I have found a few more thing that need clarification though:
* The coil form diameter for the large volume and pitch coils (L2 and L6) is different on the two parts list Ive found. Jeff Sparks parts list (http://www.thereminworld.com/files/projects/mktheremin/mkcomponents.pdf) has the form diameter at 3.30" while Phillip Neidlinger's excel parts spread sheet (http://www.neidlinger.us/keppinger.htm) lists a 3.1" diameter form. Both list the same gauge wire and # of windings??
So I guessing that the ocillators are a little forgiving and the inductance doesnt need to be dead on. ?
* Phil's list also says L1 has a double wrap with layers for craft paper soaked in shellac between windings. the other only mentions one winding, tapped at 50 turns. ? any thoughts?
Any suggestions of where to find phenolic coil forms that size. I was just planning on using my stock coil form material :heavy cardboard tubes covered with shellac or interlux wood sealer (a clear oil based sealer used to "prime" wood before applying varnish). They have about a 3.25-3.27" diameter. closer to the size stated on the jsparks list.
Also what size chassis did mr keppinger use?.. and beside phils page are there any other photos or diagrams of the layout? I want to stick with an already winning formula. Thanks for the help.
