Battery Supply for EW ? (condensed and meaningful posts)

Posted: 6/4/2013 5:20:29 AM
bisem

From: Pittsburgh, Pennsylvania

Joined: 1/1/2011

I at least understand the inefficiency part.  The EW just doesn't make this easy.  Someday I will get together with my electronics guru here in the Pitt and all the info you provided to modify the PSU.  For now I will plug in my espresso machine while I am busking....I'm sure it will make more money than my playing....LOL!   Thanks for all your input on this thread.   

BTW they released a s**t load of helium filled balloons at the Indy 500 the other day.  Live like there is no tomorrow I always say!

Posted: 6/4/2013 10:25:28 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

Bisem..

I have just seen on another thread, that you own a Subscope..

AFAIK, this theremin is based on a design which is unlikely to require +/- DC supply and therefore the voltage into it is probably from a simple DC supply - probably 12V (you would need to check)

The thing which makes the EW such a pain in terms of battery operation is its bloody AC supply! .. Any theremin requiring a simple DC supply is MUCH easier to battery power..

A lot of designers use 12V DC as their primary on-board voltage - so the board has a 12V regulator and the incoming supply needs to be minimum of 14V for good operation.. However, SOME theremins (notably the Silicon-Chip / EPE / Jaycar and their variants) use lower voltage board regulation, and will run from a supply as low as 11V, making it possible to power them directly from a 12V battery.

Check it out with the manufacturer first !!!!  - But if I was busking and had an alternative to the EW, I would certainly leave the EW and the inverter at home!

Even if you need to crank up the voltage a tad, a 3V (or 6V rechargable) in series with the 12V battery will do this.. A small sealed 6V lead battery will (in combination with the big 12V battery) provide hours of the 100mA or so needed to drive the theremin.. 3 small 6V lead batteries in series gives 18V, and a 12V regulator should handle this (again, check!) if thats whats on-board..

Fred.

"Live like there is no tomorrow I always say!" - Yeah.. Perhaps theyr right though.. Perhaps there is no tomorrow -

Completely OT WRT battery supply, but perhaps not WRT fools and helium .. Also, I utterly love this song - I was able to sing it perfectly about 20 years ago, but cant get the highs anymore... This piece just seems well suited to a theremin - perhaps replacing the flute...

Posted: 6/5/2013 5:47:53 AM
bisem

From: Pittsburgh, Pennsylvania

Joined: 1/1/2011

Fred,

Nice...thanks for sharing that! You need to come up with an appropriate video at the end of every thread on TW!

I am in contact with Dominik Bednarz the builder of my Subscope and he said hooking 12V directly to it would do the job.  I just don't want to be bouncing around his work in a busking case since it is my favorite theremin.  The EV is easier and less expensive to replace if need be....plus it looks really cool the way I have the set up designed.  

Today I went busking on the North Shore of Pittsburgh and picked a nice spot by the river where I knew there would not be much of an audience. I just wanted to get my feet wet (not in the water).  I made three dollars!  Now that I know how everything works and sounds I can move to more lucrative areas.  It was a good experiment and I did notice that it is difficult to use backing tracks from my Ipod in the open air since there is not enough feedback to keep the pitch going. I just ended up winging it solo.  At least it paid for my parking....LOL!

Brian ;^)

Posted: 6/5/2013 8:44:34 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

"You need to come up with an appropriate video at the end of every thread on TW!"

I could easily come up with a piece of music for each thread.. But alas, even though some music / song comes into my head for almost everything I read / see, most of the time "appropriateness" can be difficult to identify - certainly difficult / impossible for anyone not in my head , LOL ;-)

And then there is finding them .. For perhaps 20% of the songs in my head, I have no idea what they are or where I heard them - some of the instrumentals I just dreamed up, and other songs just start playing and I can find them by searching for a few lines of the lyrics I hear.. but others I have no idea (particularly if the singing I hear is in a different language).

But then there are those I know well, and love, and "play" frequently - Even here though, there is a "problem" - For example, "Fools Overture" - The version in my head is from SuperTramps "Even in the quietest moments" Album - It is so absolutely "embedded" in my brain in that version,  listening to any version which deviates from my "recording" is less satisfying to me.. Yeah, its a great clip - but IMO not nearly as great as the original!

Fred.  

Posted: 6/5/2013 8:59:33 PM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

Hearing a bit of "Jerusalem" sung in the last, I just must post this..

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