Korg Poly800/EX800 Users

On 22/12/12 19:08, backshall1 wrote:

> really needs more than 300ma then the voltage will drop below 9 volts. A
> large transformer type adapter that is rated for 1000ma might measure as
> high as 20V with no load on it, and only drop to 15 volts with only a
> 300ma load on it.

Mmm, not quite. An unregulated supply typically puts out √2Vnominal so
for a 9V unregulated supply you'd expect to see about 12.7V offload,
regardless of the output current.

> On the other hand, if you are using a newer switching-type adapter, it
> is probably much smaller since it does not need a big transformer in it,
> and it will put out a regulated 9V at any current level from 0-1000ma,

The output is generally electrically quieter, too, although they can
crowbar some nasty noise onto the mains supply. RFI can be a problem
with cheap ones, too.

> so there is no problem using one rated for 1000ma. A/C adapters rarely
> have markings on them to show whether they are switching supplies or
> not. You can usually tell from the size.

... or weight ;-)

--
Gordonjcp MM0YEQ