Re: why wall warts?

[Kim Flint <kflint@annihilist.com>]

At 10:49 AM -0700 7/4/99, Doug Tapia wrote:

>>Matt Davignon wrote:
>>
>>> By the way, what's with these fat plugs? All of my older 
>Electro-Harmonix
>>> effects have the regular AC plugs just like anything else in my house. 
>Now
>>> that they're being made again, they come with those annoying fat 
>plugs. How
>>> was that necessary? Newer versions of things are supposed to be 
>smaller and
>>> more convenient! The fact that my older pedals were built with those 
>nice
>>> small plugs seems to prove that those fat plugs aren't really 
>necessary!
>They
>>> could simply put the AC to DC adaptor right inside the pedal! It would 
>make
>>> the pedal a little bigger, but it would be a lot nicer!
>>
>>i read somewhere (possibly this list) that most signal processor
>>manufacturers
>>don't build in a power supply these days because 1. it is cheaper and 2. 
>it
>>helps with overseas marketability...

I think the best thing for overseas marketability is an internal supply
that auto-senses the mains voltage and sets itself correctly. The second
best thing is an internal supply with a switch for the user to set it
according to where they are. Both allow people to travel easily, and can
work anywhere without much hassle. (which simplifies mfg and distribution
too.) The third best thing is wall warts, since that requires separate wall
warts for different parts of the world, which can be a big hassle if you
can't find the right one. The worst are devices fixed to one mains voltage,
where you need to deal with transformers.


>>
>3.  Removing the power supply (or at least the step down transformer)
>from the main unit lowers the noise floor by a few dB

No, that's not really true. Only if the person designing the supply has no
idea what they are doing. How many pro studio consoles have you noticed
using wall warts? Designing clean internal supplies is not that expensive,
and not that hard. A correctly designed supply should not increase noise at
all.

If anything, wall warts are a far worse situation, since they are generally
made with cheap transformers, completely unshielded in a plastic housing.
They radiate like mad, and can cause a lot of hum in nearby audio devices.

>4.  Devices with internal power supplies have to be tested for UL
>listing, which is a pretty expensive undertaking from any perspective.

It's actually pretty easy, just some paperwork if you do the design right.
Same with CE. That's hardly a justification for using an extremely
unreliable component in pro gear. It's more like an excuse given for lazy
or inept engineering. For god's sake, toasters and hair dryers get UL
approval for direct AC connections. This is electronics 101, no rocket
science necessary!

Really, the reason you have these pieces of crap attached to your otherwise
well-made gear is because you allow it. You're the consumer, it's your
money, demand a better product!

kim

______________________________________________________________________
Kim Flint                   | Looper's Delight
kflint@annihilist.com       | http://www.annihilist.com/loop/loop.html
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