My Theremax project

The case is finished, the urethane varnish just has to cure hard.

To connect the antennae, I found 1/2 inch ring terminals at Kragen Auto Parts and reamed them out to 9/16 inch with a round file. Looks good.

The open end of the pitch antenna seemed unaesthetic, but I couldn't find a satisfactory matching plug or cap. Finally I rounded the end of a 3/8 inch dowel (same diameter as the antenna), stained and finished it to match the case, and cut off a small piece (about 1/2 inch). I put a bit of hot glue into the end of the antenna, pushed a bit of 1/4 inch dowel in flush with the metal, and added a dab of super glue to hold the finished bit of 3/8 inch dowel. Doesn't look bad.

I cleaned off the work bench (well, enough of it) and tomorrow will set up for electronic assembly.

I got things set up for assembly of the circuit board today; found a simple stool for my workbench ($8 US unassembled at Harbor Freight Tools), which will be very helpful. I am working this weekend at a small rural hospital, so won't be able to do any soldering--but when on standby I may be able to emplace some of the parts, ready to solder on Monday.

Today I got the resistors and capacitors sorted out preparatory to soldering, which I maya be able to commence on Monday. A magnifying glass is pretty much a necessity, and I was very glad I had an ohmmeter to double-check my identifiction of the resistors. Some of the color coding bands on the resistors look much the same under fluorescent lights.

Gordon--A question for you about GarageBand. What is a practical way to get the sound out of the amplifier and into the Mac so I can save and post a sound clip? Once I get my Tmax put together, if the sound is not bad I am toying with the idea of posting samples for people's comments. (Not having another theremin for comparison.)
TIA
Alan

Or out of the theremin and into the Mac, for that matter.

Hi Alan,

It depends on what Mac you've got. My previous iBook had a pretty rough built in mic and no audio in, so I bought a USB headset for Skypeing and it works just fine for recording theremin too. Put the mic as close to the centre of the speaker as is feasible.

It's a Plantronics DSP-500 headset, bought from the Apple online store. (My current macBook has a better built in mic - I used it to record the Gakken Theremin Mini pieces, but I'll be sticking with the headset for recording my real theremins.)

From a recording music point of view I prefer to mike the amp than take a direct feed from the theremin as I regard my amp as part of my instrument. For audio samples I might not want the extra colouring that the amp imparts. My current macBook has line-in, so I could use that directly - but if it didn't then there are audio to usb converters available. (It also has optical digital in, but I don't know anything about that. It sounds expensive!)

The quick and dirty way to take a feed is using a line splitter - an adaptor with a 1/4" mono jack plug at one end and two 1/4" mono jack sockets at the other (or vice versa.) The downside is that you are halving the volume when you split the signal. The proper solution is (I believe) called a D.I. Box - but someone else would need to tell you about those.

Or your amp might have a line-out socket, in which case use that. (Headphone sockets are useless - they mute the darned amp.)

Whichever method you use, select it in system preferences, check the levels on the meter (if it is adjustable), open Garageband, create a real audio track and press record. :-)

Oops. Double posting.

Many thanks, Gordon. I got home from working the weekend a couple of hours ago, showered, had dinner, a bit of liquid bread, and am currently relaxing. Checked my Mac--a PowerMac G4 desktop, and found it has an audio in port. But as it happens, I also have a Plantronics USB headset mic that I got anticipating I would use Skype--but put aside when I discovered Jajah.com. I had wondered if I could use the headset mic, because it seems such a simple solution. Thanks to your reassurance, I will. The room with the G4 is rather too crowded to add the theremin and associated gadgets--but I can put the theremin in the next room, run a cable through the door and get the amp close enough to the computer. And I should be the one to apologize for double posting--wasn't sure you would see my question here, so put it on the front page thread also.

Oh, one more question: You say to "check the levels on the meter"--what meter? Is that something in Preferences?

Yes.

In the Sound prefs panel, under the Input tab there should be a input level meter and an input volume slider.

like this (http://www.wap.org/journal/digitizingcassettes/ss1soundpanel.jpg)


N.B. On the subject of GarageBand - one thing it doesn't do is noise removal. For that I use the shareware product Amadeus Pro (http://www.hairersoft.com/AmadeusPro/AmadeusPro.html). Very good.