Opinions on replacement PS for my M-Audio Keystation 49e

[isfahani]

Hi. I am trying to avoid blowing money when I don't have to... The OEM is at 500mA, but I have a 300mA and a 600mA 9v on hand and I wanted to make sure before plugging them in that it's safe to do so, one or the other.

I came across this statement

Voltage rating aside for the moment, the difference between a 300mA supply and a 500mA supply is only meaningful if the device tries to draw more than 300mA. So, you could use a 500mA supply without any danger to a device that only tries to draw 300mA. On the other hand, if your device attempts to draw 500mA and the supply can only source 300mA, you'll most likely destroy the power supply.

while searching for info on google.

In reading this, it seems that my best bet would be to use the 600mA one, is this so? Help is much appreciated.

 

[dementedchord]

yes the 600 should work... the issue also is what the polarity is so check that as well... and the third issue of course is the voltage... dont exceed the recommended...

 

[isfahani]

Yep... I understand voltage and polarity, but not the thing about mA and the 'headroom' - Thanks for the input, it should be good to go.

 

[dintymoore]

I found that a whole bunch of ac adapters worked with my M-Audio keyboards. The polarity needs to be correct, and you need to have the same or more ma than specified. The ac adapter needs to say it has higher or equal the amount of ma than the keyboard needs.

Also, some ac adapters put out ac, not dc! Not many, but a few so look out for that. Some that came with AT&T phone answering machines were like that. So I always make sure we're talking ac in, dc out.

Here's another thing they don't tell you: even if you don't hook the keyboard up with USB for data, if you use only the MIDI out jack, you can still use the USB jack just for a power supply! That can be very handy and that's not mentioned in any of the manuals. I did it for a long time before I was using USB for data transmission. Just use the USB for an ac adapter and the MIDI jack to hook up your gear and it works fine. Saves space and doesn't draw current when the keyboard is off.

Can you imagine how much electricity is being wasted around the world right now by ac adapters just sitting there plugged into something that's been off for months. Or not even plugged into anything, just sitting there being warm. I've thought that in the future it might be worth running 9v dc power from the fusebox throughout a house that would take care of that problem. Or maybe you could put a relay in an ac adapter that would switch off if there was no load - how hard could that be?