Elysian Theremin Power Supply

Anyone out there know the voltage or amps for this beast? Reached out to Jake in the UK but got no reply. A friend gifted it. I think it's 15volt but now idea the amps. Looking to get a off the shelf supply for it. Thanks all!

Kalib, You need to be careful in how much you invest in this project, as it only has value to you.

You should post a schematic or picture of the insides.

Christopher

Thanks Christopher,

Was able to confirm it is 15volt and tip positive. Grabbed a $15 regulated various AC adapter that can handle up to 2Amp from Amazon and it is working! Well, continuous pitch out, and the pitch trim is.

It seems the volume out is stuck to near null. As it is only a faint output to the headphone jack and the Amplitude pot and headphone out pot have no effect. There are adjustment pots on the bottom of the motherboard, it may be the volume needs adjustment. I just need to find a copy of the manual to be sure.

Kalib

http://uisoftware.com/PAGES/links_images/Elysian%20Top%20of%20Board.JPG

http://uisoftware.com/PAGES/links_images/Elysian%20Bottom%20of%20Board.JPG

A copy of the manual is good. Even better, if there is an electrical diagram of the device.

The build is very nicely done. The designer is very good, understands that the need for specially wound coils and using ancient parts from ebay is an internet myth or lack of knowledge or ignorance. The output should be able to power a speaker directly. My guess it operates near the same frequencies as the EtherWave Standard, under 500khz.

Those are two variable capacitors on the bottom of board. They dial in the Pitch & Volume frequencies so you find Null or Zero point. Set the two knobs on the front panel to half way. Sweep the dial of "analog" AM Radio and you will hear the frequencies the two oscillators are operating at or a harmonic of it. You will hear blank spots in the static or a chirp while tapping the 1000uh chokes. You will also hear the heterodyning whistle in this process. The variable capacitors should not be off by much if at all but this radio method should allow you to get things working.

Get us a sweep sound sample. My guess more like the EWS.

Valery we are making progress as the last of special knowledge has been given to me.

Christopher

Thank you Christopher!

I did something similar back when I build a PAIA Theremin in the 90's. Had an AM radio to tune the beast. Ran a jumper and tuned the AM radio to a specific target frequency and adjusted the pot. Fine tuning was with the from panel potentiometer. Sounds like this will be the same. Any guess what frequency to set the AM radio too (if I'm understanding correctly)?

Valery,
so far I've not found a diagram online, let alone a manual in PDF. Someone here mentioned the manual in a post but it was many years ago and I couldn't re-find the post. So far Jake hasn't replied to emails. I think it's just that the volume variable capacitor shifted as it bounced around on the plane trip - tho' it was bubble wrapped.

Thanks again for the help,
Kalib

kalib said: "Any guess what frequency to set the AM radio too (if I'm understanding correctly)?"

In theremins there is no special frequency unless you are tuning to a tuned Pitch antenna. Range I like is 200 khz to 1000 khz

Just sweep the entire AM radio dial tapping one of the inductors, my guess around 1000 khz which will be a harmonic of the actual frequency.

Usually the Pitch frequency will be slightly off of double or half of the volume frequency so they do not interfere with one another.

Christopher

"tapping one of the inductors" - do you mean listen for it as scan the AM freq range, or do you mean something physical? The PAIA used a physical jumper (using a clamp) when tuning with an AM radio. So that's my point of reference - last done almost two decades ago.

Physically taping the coil or oscillator transistor with the tip of your finger at the same time you scan the AM dial. If the oscillator is working you will find the frequency you are working with. An oscilloscope using the 10x 10 meg probe on the emitter of the transistor is useful but most people do not have one.

Edit: Listening to the higher end of heterodyning over the AM radio works but not without misleading interference from radio stations.

This stuff is so much fun, like my first crystal radio and I picked up the ham radio operator transmitting in the neighborhood.

Christopher

Hi Christopher and Valery,

Jake got back to me, he regularly uses a different email account now. Here is his reply: "Dear Kalib, It sounds like you have a fault with the output amplifier which uses an LM380 chip. Unfortunately it is soldered into the board for heat sinking so it is hard to remove. These chips rarely fail, so it could be something simple like a dry joint. You could plug it into a guitar amp for now. Please find attached the manual and circuit diagram.
 Regards, Jake" P.S. note new phone number 01597 829 102 and email jacob.rothman@hotmail.com

Here is the schematic and manual:

uisoftware.com/PAGES/links_images/elysian 2014.png
uisoftware.com/PAGES/links_images/_Elysian Theremin Owner's Manual.pdf

I've just read that the unit must be Earthed. I'm assuming this the same as grounded in the US. Since I'm using this adapter https://www.amazon.com/gp/product/B015H0UPWU/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 perhaps the lack of a ground plug is causing the issue.

Will look about for one...

K

p.s. I tested the old power supply that was causing hum, and it was 19volt not 15v so that may have been the source of the hum issue. It is grounded but did not produce audio out in Washington as it had in California. I've checked the wall ground is good.