Using a battery to power the Burns B3 Theremins

Has anyone used a battery to power their Burns B3 (standard, deluxe, or pro)?

The wall-wart that came with my B3 is rated at 9v, 200mA
Would it be safe to use a 12v Lithium-Ion battery for this?

If the wall-wart reads 9v why don't you simply use 9v battery?

I have several 12v LiIo batteries already, whereas I'd need to buy a 9v LiIo batter.

I thought I read elsewhere on this forum where someone used a 12v supply for a B3, but couldn't find the post.

Greetings! I have a B3 deluxe theremin. When I received it, I immediately began to carefully consider its device and circuit. An 78L09 stabilizer is installed at the power supply input. It stabilizes the power at a level of 9 volts, but for its correct operation, a voltage of about 12-30 volts is required.

Therefore, you can safely apply a voltage of 12 volts to the input of the power connector, observing the necessary polarity.
P.S. I have tried different wall warts, but unfortunately they all distort the theremin's signal. I think using a battery allows you to hear a cleaner sound.

For my Subscope Voicematic 3 I use a battery pack of 4 9900mAh rechargeables with a total of 14.8 V.   They last a long time!

You should look inside and check the part number of the main voltage regulator.  If it's a 78L09, the 12V pack will work fine (down to about 11V).  If it's a 78L12, you will need around 14V to run it.

Most important point!