Korg Poly800/EX800 Users

Somehow, nobody seems to have pointed out the major differences between a modern-day regulated switching supply and an old fashioned large transformer type adapter.

The old transformer type adapters are non-regulated, and the voltage varies with the current that is being used. If it is rated for 9VDC at 300ma, it probably measures 12-13 volts when nothing is plugged into it. The voltage will drop as you draw more current, and if your equipment 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. That might put a bit too much stress on the 9v to 5v regulator circuit inside the Poly-800.

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, 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. If not, just check the voltage output with nothing plugged into it. If it is 11 volts or higher, it is an old transformer type. If it is above 15 volts, then you may be shortening the life of some of the power transistors in the 5V regulator in the Poly-800.

Don Backshall