I have an M-Audio 88 Hammer Midi keyboard. When my digital piano stopped working and proved to be un-repairable I decided to turn my M-Audio into a stand alone piano rather than connect it to a computer or buy a new digital piano. To this end I searched for piano modules and finally settled on the miditech piano mini ii as being the right one. The price is right and it does all I need it to do apart from have a built in metronome for when I am using headphones. So I ordered the Piano mini ii. Purchase and delivery all great. The actual module itself is well built and sounds great. Getting to understand the set up and what the screen was telling me was a little confusing at first as the instructions aren't brilliant but it only took 10 minutes to figure it out. The only problem I have had came when I plugged my keyboard into the USB port of the module. It didn't work. Hitting any of the keys produced no sound and the midi activity lights on the module did not flash. The keyboard was getting power from the module as the keyboard lights came up but no midi activity. I have a little 25 key midi keyboard, so I plugged that in and it worked fine immediately. Lights, sound, action! So I tried plugging my keyboard into it's own power supply and then connected the 5 pin midi out socket of the keyboard to the midi in five pin to 3.6mm jack converter cable that comes with the piano mini and plugged that into the midi in jack on the piano mini. It worked a treat. Everything started working fine. I checked the miditech.de website and found in the FAQ's that the USB port on the piano mini will only work with keyboards with a low power consumption. If the keyboard connected requires more power than the USB can supply then you won't get any sound, even if the keyboard shows that it is powered up. I cured the metronome issue by buying a small cheap audio mixer so that I can use a metronome I already have and just mix it with the output of the piano mini so I can hear both over the same pair of headphones. All in all a great little device that now does everything I want. Thanks for the great service.