USB vs external power question

[lunalone]

Hi,

I'm having a problem when using external power for the Megadrum module
While the MD is powered via USB all the instruments play nicely. As soon as I disconnect USB and go to external power. The same presets are producing different dynamic behaviour on every instrument. Closed HiHat for example only works when played very softly, as soon as I apply more pressure, it is not triggered at all.

As soon as I switch back to USB power I load the same presets and it's working again. Any suggestions? I really need external power for my live setup. Thank you guys, for helping out.

[airflamesred]

Well that doesn't really make sense does it. It's just a power suppy. Have you got 'auto load config' set to yes?

[dmitri]

What is this external power supply? Is it regulated 5V? Did you measure it? It may also have too much ripple compared to 5V from PC USB.
Also, if it is above 6V you may damage MegaDrum.

[lunalone]

The power supply is rated 5V. I'll have to figure out how to measure USB Pins on the power adapter.

I don't think this is software related. Auto load config is set to yes. But I was loading the slots manually also. Everytime it worked flawlessly on USB power.

I'll also check different USB adapters. I'm pretty sure that this is the problem. Can you tell what too much ripple is in numbers? Does it still work, for example, if the supply only had 4,5V?

Thanks

[dmitri]

Ripple is a leftover of AC (50/60Hz for a non-switching PC or high frequency for a switching PS) passed to output DC. I don't think you can measure it without an oscilloscope. A good regulated PS should have almost no ripple.
For MegaDrum settings to be consistent between a PC USB and an external 5V PS the output voltage on the external PS should be the same as from the PC USB.
4.5V may not be enough, it really should be close to 5V.