“We proudly announce the completion of the Diana Series of amplification with the introduction of two new models.  Following on from our Diana integrated amplifier, the Diana Forte – arguably the most powerful Single Ended Triode (SET) stereo amplifier in the World and the Diana Mezzo, its accompanying Class A Pre-amplifier.

The two models share the majority of circuits with the Diana integrated and technically, is a two chassis improved version of the integrated. Customers have the benefit of purchasing the Diana Mezzo Pre-amplifier and later getting Diana Forte for a perfect match.”

Stavros Danos

The Diana Mezzo is an improved version of the Diana Integrated’s pre-amplifier stage. At its heart, the Diana Mezzo is a Single Ended Triode amplifier boasting an 814 Direct Heated thoriated tungsten DHT.  This 814 Pentode tube in triode mode is more linear than a 300B tube.

The output transformer is a Double C Amorphous Core, bifilar wound output transformer. Signal attenuation is performed by a relay-switched array of resistors, in a shunt/ladder hybrid mode.

A pair of Xenon gas rectifiers are used as rectifiers of the High Voltage PSU. These rectifiers were developed as drop in replacements for some well known mercury rectifiers when mercury was labeled unsafe. So while they present the technical characteristics of a mercury rectifier, they are safe to operate.

The high speed capacitor banks are double choke filtered. Filament PSUs are quadruple filtered using a cascade of choke/resistor-cap pi filters providing very low noise floor for the sensitive filaments of the DHTs.

Tubes: 2 x 814, 2 x 3b28
Gain: X7 (16db)
Attenuation level: 61 X 1db steps
Maximum signal input overload: 25V
Signal bandwidth @ 20V rms: 10Hz-120Khz (-3db)
Dimensions: 500mm W x 350mm D x 340mm H
Weight:  55Kg