Janszen Speakers - help


A friend of mine inherited some Janszen Electrostatic speakers. I want to help him set them up. He doesn't have any stereo equipment, so I am wondering what sort of amp would be needed to drive them. I can't find any information about these speakers. Some pictures are here and here.

They are big, about 15 inches square and 50 inches tall. The top black part just lifts off of the bottom, and is connected by a plug and socket, and some dowels that align the socket. The close up is of the bottom of the speaker.
markhyams
I should add that it looks like there is a 12-volt input on the bottom of each speaker, as well as some sort of knob that is very hard to turn. Thanks for your help!
There needs to be some sort of power for the electrostatic tweeters. Usually, Janszen built that into them and one only needed to connect them to an AC outlet. These seem to need an external transformer or PS. Do you have them? Can you post a picture of the bottom?

Kal
There is one external transformer, like wall-wort style. Also the second link up in the original post is a picture of the bottom. Thanks Kal!