Re: wall wart grief

[David Myers <dmgraph@earthlink.net>]

>> David,
>> Units that require an AC supply will not work with a DC input
>> voltage.
>> Will Brake
>> Soul Fruit
> 
> This statement is not true.  I know because I have powered ac input
> devices (roland gr-09) with the same value dc input.  It does work.  I
> am an electrical engineer.  The ac input device has diodes inside to
> rectify the ac.  If you pass a dc voltage into the rectifiers, they
> simply pass the current through, if they are forward biased.  As long
> as you do not exceed the diode's voltage rating, and current rating
> there will be no problems.  This has been discussed here before.
> 
> bret

This is exactly what I was thinking, and was gratified to get your resonse,
Bret.  But then:

>I totally agree with your expert explanation. You are certainly correct.
>In theory, definite. In practice, no promises. What you must take into
>account is the many different makes and models out there. I have seen
>many pieces of gear fail because an incorrect type of supply was used. I
>suppose I should have been more clear. It is not recommended to use the
>wrong type of supply.

>For example:

>If you use an off brand wall wart to power certain BOSS pedals or Drum
>Machines, you will get noisy output or erratic operation. This is
>because the BOSS supplies have filtering and regulation. Some older
>Alesis pieces fail when used with a DC supply. I've seen it happen!

>You go ahead and take the gamble on the quality of the design, it keeps
>me in business!

>For what it's worth

>Will Brake

Oy!  Wish life were simpler, eh?  I have three Korg Kaoss pads, a DL-4, an
Alesis AirFX and Nanocomp and a couple of simple self made mixers based on
an AC wart (and a Littlelite!).  I am very inclined to the "if you pass a 
dc
voltage into the rectifiers, they simply pass the current through" theory,
so if anyone here has experience with these specific devices going up in
smoke I'd appreciate hearing about it before I make the plunge.  Otherwise,
maybe I'll be giving you business, Will...

DLM