of zweidraht - vierdrahtbetrieb switchable allverstärker

摘要

The amplifier has equaliser, balancing and amplifier units symmetrically mounted around the ringing generator unit. They are all plugged into a rack insert holding several universal amplifiers and permanently wired. The amplifier switching over to two-wire or four-wire operation is achieved by changing places of balancing and amplifier unit belonging together. In two-wire operation the ringing generator is in the middle, with a balancing, an amplifier and an equaliser units on each side, in this order; in four-wire operation, after changing places of the adjacent amplifier and balancing units, two balancing and two equaliser units are between amplifier units of two adjacent universal amplifiers.