The ProLogue Four is an EL-34 based vacuum-tube stereo power amplifier, hand-made with the finest point to point wiring, using workmanship that is equal to or better than any product you can buy at any price.
The amplifier is built using finest premium parts. A toroidal transformer for the powersupply. Custom designed -in conjunction with one of the most prestigious transformer-designers in the USA- encapsulated output transformers for lowest hum, wide bandwidth for great bass and extended highs. Ceramic tube sockets. Nichicon and Realcap capacitors. Gold plated heavy duty speaker terminals and gold plated input jacks.It is enclosed inside a heavy gauge steel, fully vented chassis with five coats of finish. Each coat hand rubbed and polished.
The Adaptive AutoBias™ circuit, an exclusive to PrimaLuna, monitors and smoothfully adjusts bias constantly and instantly, reducing maintenance and increasing performance because of a dramatic reduction in distortion. For extended life of tubes and switches plus a reduced chance of tube failure/shorts, the amplifier uses a soft-start circuit.
Tube plate fusing is used to protect the output stage. Other amps might need a trip to the shop if a tube fails. Not this one. Just plug in a new tube and fuse, and go.