Burns B3 Deluxe Power Supply - advice please.

Posted: 9/14/2010 1:17:30 PM
bruce

From: Scotland

Joined: 9/14/2010

Hello, i am waiting for a new Burns B3 Deluxe to arrive from USA (my first Theremin) and would like to know what power adapter i will need to buy. I have seen a 100w 240v-110v step-down unit on Ebay, will that work or am i looking at the wrong thing? Any info or advice will be greatly appreciated. Cheers, Bruce
Posted: 9/14/2010 3:05:10 PM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

Why don't you shoot Dan Burns an email? I'm sure he would be more than happy to steer you in the right direction.
Posted: 9/14/2010 4:41:07 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

These step-up/down transformers dont't work well for the B3 but risk to turn it into a radio receiver.

When your B3 arrives you have to look first if it has a plug hole for the power supply or if the cable is attached and soldered inside (Dan Burns seems to like to change the system from time to time). If there is a plug hole, I can provide you a fitting 230V power supply. If the cable is attached, some modifications are needed. It will depend on your soldering skills if you may do it yourself or if you will need professional help.

You may contact me via the contact form of my website http://theremin.tfrenkel.com
Posted: 9/15/2010 11:37:31 PM
bruce

From: Scotland

Joined: 9/14/2010

Hello & thank you for the advice, i just received the following advice from Dan in USA and it would seem that the step-down devise should work okay;

The easiest way to address the power mismatch problem is to purchase a power converter. Something like this will do the
trick:

http://www.amazon.co.uk/gp/product/B000NJ26X2/ref=s9_simz_gw_s1_p23_i1?pf_rd_m=A3P5ROKL5A1OLE&pf_rd_s=center-1&pf_rd_r=1JQ8D01E9QG7PJ7QTCJ6&pf_rd_t=101&pf_rd_p=467198433&pf_rd_i=468294

Or you replace the supply with one that is of the UK standard. If just needs to supply between 12 and 24 volts DC for the instrument to play properly. Wattage is not an issue. The theremin draws very little power. Thanks! Dan
Posted: 9/27/2010 8:43:14 AM
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

If you have the option of buying a DC supply, go for this!
Thierry is right! Whatever anyone else says, adding a step-down (240 -> 110) transformer is a poor choice unless one is forced to do this... This applies to all equipment, but particularly to Theremins!

With a Theremin, there are many additional factors to take into account - these include (but are not limited to) supply capacitance AND INDUCTANCE.. An aditional transformer increases the chances of problems.. Quite often one will be lucky, but sometimes you wont be.

A simple DC supply (NOT switching type) is more efficient, likely to cost less, and less likely to cause problems.

The supply you suggested looks to me like a SMPSU - these are often a particularly bad choice, as they can output (or radiate) high frequency noise.

Fred.
Posted: 9/27/2010 9:10:55 AM
bruce

From: Scotland

Joined: 9/14/2010

Hi Fred,
Many thanks for that info, since posting my original request for advice and then receiving the advice from Dan in USA the B3 has arrived and came with a power supply like those with a laptop computer & supplying the B3 with 12 volts so it is an easy fix. My confusion was thinking it required a 110v supply directly to the instrument. Cheers, Bruce
Posted: 9/27/2010 9:16:32 AM
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

Hi Bruce,

You want a linear supply, NOT a switch-mode supply! SMPS can be ok, but linear is always ok!

If you can get a linear regulated supply these are best.. I have a thing about power supplies.. I like the supply to be as clean as possible - On my Theremins I have gross overkill in the regulation circuits - but a lot of manufacturers downplay the importance of the supply and leave the instrument open to abuse from supply borne interference.

Something like the 15V version of these: http://www.maplin.co.uk/module.aspx?moduleno=13453 is your minimum I would say.. I would go for 15V to ensure enough headroom for the regulators in the Theremin.

Fred
Posted: 9/27/2010 10:09:37 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

Take care of the free-run voltage of the power supply! I had once to fix a "grilled" B3 after a Swiss client connected an unregulated 18V power supply which delivered 37V into the poor B3 because it draw only a very weak current.

Fortunately, the internal 78L12 regulator died without sending this overload to the other components, so that I had only to replace the regulator.
Posted: 9/27/2010 10:49:10 AM
bruce

From: Scotland

Joined: 9/14/2010

Hi Fred & Thierry, many thanks to you both for your help & useful advice. I will be sure to put my multimeter on the power supply before i connect it to the B3! Bruce
Posted: 9/27/2010 12:08:01 PM
AlKhwarizmi

From: A Coruña, Spain

Joined: 9/26/2010

I have a Burns B3 (the standard model, not the Deluxe) that I bought last week and I'm using it in Europe with a 220V to 110V converter. At the moment it's working fine, but from what you are posting it seems that this is not recommendable. What kinds of problems could happen? Are you talking about small issues (loss of precision in tuning, etc.) or could this actually damage/break my theremin?

You must be logged in to post a reply. Please log in or register for a new account.