The answer of what the voltage tolerance of the Beat Buddy is will be interesting. Not all 9vdc adapters are created equally and most older adapters that use a transformer for conversion are generally not regulated like the new ones that are solid state and regulated to 9 volts regardless of load. I got a few of my old transformer type adapters out and checked the ‘no-load’ output voltage. I didn’t try any loads, but typically the voltage is load dependent and may not necessarily be at 9 volts when loaded. It could be higher, but as long as the rated load isn’t exceeded shouldn’t be much less than 9 volts. I don’t think a person would think twice about using an adapter as long as it said 9 volts, neg tip, and had an adequate milliamp rating, but if the BB tolerance is particularly tight, perhaps there may be a risk of damage.
I had done some current draw checks of the BB a while back (don’t have the numbers I got) and I do recall the current did vary some depending on what the BB was doing. I think during the power on it pulled the most current and then settled back. Switching of some functions caused small changes in the milliamps.
A few 9 volt adapters I pulled out and checked ‘no load’ voltage. All were neg tip and of a ma rating that should power the BB. Nope, I’m not going to try one to see what happens
KORG: 10.2, 13.0
Zoom: 12.27, 13.58