This is the Philips L-300 audio line transformer.

Its Marantz brother is the Marantz DLT-1 digital line transformer

Philips L300 audio line transformer Philips L300 audio line transformer Philips L300 audio line transformer Philips L300 audio line transformer Philips L300 audio line transformer Philips L300 audio line transformer Philips L300 audio line transformer Philips L300 audio line transformer