I have a small battery powered 25W amplifier/speaker combo. KustomSound CB25X, with two 6V 4.5Ah SLA batteries wired in series for 12V. Fully charged, the voltage seems to be close to 13V.
I also have a mixer - Yamaha MG06X, which runs off a 12V wall wart. The voltage off the wall wart is 12.3V.
The mixer is rated for 24W but it's unlikely I'll ever be using it at full power. Same goes for the speaker.
I also got myself a little preassembled LM2577 DC/DC switching voltage booster from online.
My question: Can I run the mixer off of the amp battery with the DC/DC booster? Can it tolerate a volt or so above its rated 12V e.g. when the battery is fully charged? (Because that DC/DC chip can't lower the voltage, unfortunately.)
Alternatively: can I wire the DC/DC booster across just one battery? Will that be bad for the amp or the batteries or the mixer? EDIT: I've been informed that's not a good idea, so ignore this paragraph.