D2O is a low noise discrete microphone preamp, it is a further development of the famous German V series preamps, widely recognized as one of the best sounding preamps. These preamps were used at Abbey Road to record The Beatles, Pink Floyd to name a view. Today the V series preamps are still in demand, although most units are now at least 35 years old and need to be rebuilt or refurbished.
The D2O mono is a single unit preamp housed in a rugged aluminum enclosure. The portable format is ideal for the new generation of mobile recording interfaces.
D2O's general layout consists of a Lundahl 1571 input transformer followed by 2 single ended gain stages. The second gain stage can be selected to be either a high gain Fet or a Tube stage. when the high gain, all Fet circuit is engaged D2O becomes an ideal companion for microphones with a relatively low output like ribbon microphones. With the hybrid Fet/Tube circuit is engaged the sonic benefits of having a tube in the signal path can be utilised. Output drive is supplied by a discrete low impedance Fet buffer with superb sonic properties. Quality Paper in oil coupling capacitors are used, all other used components are high-end grade as well.
Low noise / low esr power supply
In single ended preamp designs the quality of the power supply is crucial, D2O is fitted with a discrete low esr voltage regulator built with low noise components enabling optimal performance to the amplifier circuit.
Switchable transformer ratio / input impedance
By selecting the transformer ratio switch a selection between a 1:1.75 (LO) or 1:3.5 (HI) transformation ratio can be made. Besides setting voltage gain, this also switches the input impedance of the amplifier between 2.25KOhm and 6.25 KOhm. Different transformation rate and impedance selection options are very desirable as they allow for more sonic options from the connected microphone.
Selectable all Fet or Tube-Fet circuit
The Tube-Fet switch determines whether D2O functions as an hi gain, all Fet or hybrid Tube-Fet circuit, each with its unique sonic character.
"What is the impedance of the DI input of the d2o preamp? "
"How long will the tube last in the d2o preamp by regular use?"