SPL GainStation 1 - Tube Microphone and Instrument Preamplifier

The GainStation 1 is a discrete high-end preamplifier that combines Class-A clean gain with high-sounding tube gain and operates with an operating voltage of 60 V.

Features:

• Separately controllable transistor and tube preamplifiers
• The (switchable) tube stage delivers subtle to brutal tube saturation
• Only high-quality MKP film capacitors are used in the tube stage
• Peak/FET Limiter
• Polarity-reversal stage
• 48-Volt phantom power
• LED level indicator
• Switchable impedance adjustment for the microphone input (200 ?, 1,2 k? and 10 k?)
• Discrete operational amplifiers in Class A technology instead of industrial ICs
• Amplifier slew rate of under 100 V/µs
• Gas-encapsulated relays with gold-plated contacts
• Resistors with 0.1 % tolerance in the entire audio path
• Power supply with double shielding, each voltage with its own winding and regulation

Class-A meets Tube
The GainStation 1 is a hybrid preamplifier consisting of a discrete Class A transistor stage and tube stage. The hybrid design of the preamplifier combines the advantages of semiconductors (high dynamics with low distortion, low noise) with the musical qualities of tube sound (pleasant high/overtone spectrum, beautiful three-dimensionality). The Class A transistor preamplifier is based on our DMPA operational amplifiers, which operate with an operating voltage of +/- 30 V. The preamplifier has a Butterworth Hi Pass filter, polarity inversion, impedance selection, 48 V phantom power and a limiter.

Clean Gain
The Clean Gain stage is a balanced instrumentation amplifier built with our DMPAs (Discrete Mic Pre Amp, 60 Volt rail). In Class A mode, both end transistors always remain in a conducting state, thus avoiding crossover distortion. With a slew rate of over 100 V/µs, it is capable of amplifying even fast details and high frequencies cleanly and with low distortion.

Tube Gain
The tube gain stage is equipped with a 12 AX 7 LPS. It impresses with good noise figures and an open and clear sound image. As decoupling capacitor a WIMA MKP type is used, which is very generously dimensioned with 2.2 µF, in order to work clean and powerful also in the bass range.

HiZ/Line Input
The instrument input is a discrete impedance converter that also operates in class A mode. The core is a low-noise field-effect transistor, which is ideally suited as an impedance converter due to its very high input resistance.

Input / Output Stages
The input differential amplifiers are constructed with closely toleranced and thermally coupled transistor pairs. The output stage operates as a current amplifier, which also offers pure class A operation with over 6mA quiescent current. DC voltage components are eliminated with an active servo circuit instead of coupling capacitors.

AD Input 2
The optional converter has two channels and can therefore convert an external mono signal in parallel with the GainStation 1.