Ed,
That was interesting. I couldn't figure out why my DR770 drum machine took a wall-wart to convert to 12 v AC !! Now I guess I know.
Thanks
James R. Acker
jacker@... listen to my music at.....
==============================================================
My current songs can be now heard at my site:
http://home.online.no/~jacker/ ----- Original Message -----
Fra: Ed Edwards <edward.edwards@...>
Til: <AN1x-list@yahoogroups.com>
Sendt: 1. oktober 2001 05:30
Emne: Re: [AN1x-list] an1x construction. (Wall Warts of all sorts)
> Wall Warts
>
> In a previous job I was a Test Engineer for an independent standards and
> compliance lab. We tested many types of equipment to different regulations
> and rules - governmental, military, insurance, whatever. I personally had
> the privilege of working with Korg, Shure, ATT, IBM and other big names.
> Here's what I learned about wall warts:
>
> In the USA, the testing requirements for electrical saftey are different for
> products which require less than 48 volts input to the chassis. If a
> product required more, it needed to meet tougher standards to be allowed to
> be sold, and these standards often would require more circuitry, and
> therefore would be more expensive. Therefore, a lot of companies chose to
> have the AC converted down to less than 48 volts through a power converter
> (wall wart) and then sent to the device through a small twin lead wire
> ending in a small plug. This design decision was nothing more than a cost
> saving feature (detriment) in many cases.
>
> My personal advice on gear that uses wall warts is to make very sure that
> you have routed the tiny, skinny cable in a way that nobody trips over it.
> I have repaired many circuit boards that were really hurt by a kick or an
> unexpected pull on these hard to see wires. I try to route mine down the
> side of the keyboard stand and even sometimes tape it down for safety.
>
> Equipment that has the standard IEC male receptacle on the back - that takes
> the fully detachable and rugged cable which gets the full AC voltage from
> the wall (and is international in design) is much more rugged in general,
> surviving trip overs and other abuse... It is much more "road worthy".
>
> Generally, all of the curcuitry in a wall wart is usually this: a
> transformer, some diodes and maybe some capacitors. These components can be
> easily built into the unit. Tawdry and cheap design is why we suffer with
> these stupid warty chunks of plastic and metal that take up so much space.
> In the back of my 12 space rack I have to stuff 5 ugly wall warts which
> hardly fit.
>
> Ed Edwards
> Leader: Ezekiel's Wheel® »»»»Retro-Progressive Rock««««
> http://www.untiedmusic.com/ezekiel
> http://artists.mp3s.com/artists/227/ezekiels_wheel.html
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