Korg Poly800/EX800 Users

Unregulated adapters will only deliver their rated voltage (e.g. 9v) 
at their rated current (e.g. 300mA) and so can measure quite high 
when not connected, while a regulated adapter will hold the voltage 
at the rated amount under almost any circumstances (within it's 
ratings) The unregulated adapters are usually a bit cheaper.
  The Poly800 requires 9v DC, centre negative, same as most Boss and 
similar effects pedals, this is pretty much a music industry 
standard. (or about as close as you get to a standard!) They will 
probably run happily from slightly more or less than this, but in 
terms of noise into the circuit, you would be better off with a 
regulated adapter, as they usually have better filtering as well.
  The current rating is not marked on the unit, but someone said that 
the manual states 300mA, which sounds reasonable to me. A higher 
current rating (e.g. 1A) is fine with a regulated adapter but may 
cause problems with higher voltages from an unregulated adapter.
 Usually manuals state that you should only use the unit with the 
genuine manufacturers adapter, or your unit will generate lots of 
smoke. This is partially commercial (they make more profit from you) 
but also to discourage idiots from connecting any sort of adaptor 
that fits the unit without checking the voltage ratings and polarity. 
Reverse polarity will most likely make the smoke come out... A 100ma 
adaptor plugged into a device that requires 300mA will probably 
overheat if it doesn't have a fuse, and may catch fire!
  A higher line voltage (apart from the 110-240 jump, which will 
destroy the adaptor itself, I am talking more about 110-120v or 220-
240v) will make a proportionately higher output voltage from the 
output, unless it is regulated. (even if it is regulated, if the 
difference is enough, it may be too high for the regulator circuit)
  Hope this clears things up and didn't confuse anyone even more....




--- In korgpolyex@yahoogroups.com, Shayne Cafferata <scafferata@s...> 
wrote:
> >   I have a Korg 9V 300ma adaptor that came with my midi
> > pedalboard, and guess what?  It's putting out 11 volts!  Go 
figure.
> 
> i measured all of my power supplies a while back a discovered that 
most of them were putting out 1 or 2 volts more than their rating, 
the biggest discrepancy being a 9v that was putting out something 
like 12 or 13.
> 
> shayne