(PICTURE DELETED) I can see three balanced mike transformers and a heap of hard-wired Veroboard! That’s how stuff used to be made a lot, although I usually designed my own boards to match the circuit diagram. It’s got Nicad batteries, charged up from the front panel by a couple of sockets. I also noticed in the Ebay ad that it’s got a two frequency test oscillator. You’d use this for various purposes; you could send the signal through your chains to check for distortion; you could set up your meter (the one on top of the case) so that it read 0Db for whatever level you’d choose. Quite handy really, and all in a bullet-proof box!
Have you bought it yet? It should have more than enough analogue sound to satisfy any man!