6V power cord into 5V device?

Actually, don't worry about it. I forgot that I had a multi-voltage charger.

Remember you're still at risk of killing it if you don't know the polarity of the DC socket.

For the record, don't use a 6V plugpack for a 5V device. Also if you're playing games with plugpacks, remeber the difference between regulated and unregulated plugpacks. Your bluetooth speaker probably expects to be used with a regulated plugpack, and an unregulated one (such as most transformer plugpacks) wouldn't be suitable.

Also even if it seems to be OK with the higher voltage, it may be dissipating extra heat. It could even become a fire risk.

Sylvia.

Max volume goes to 11, instead of 10.