The GainStation8 is a superb studio or live front end providing the unsurpassed sound qualitites of exquisite, high-end analog—and exactly the kind of optimal input results needed in digital mixing. Its state-of-the-art design includes switchable pre-output stage peak and FET mode limiting, three input levels for microphone impedence matching, phase reversal, 50Hz high pass filter, 48-volt phantom power, source switching and variable-luminescence LED level indicators.
GainStation preamplifier stages are based on newly developed fully discrete components operating on a 60-volt rail. That doubles the voltage in traditional preamplifier designs, resulting in a superior 130dB dynamic range and an extraordinarily alive, detailed aural image.

The advent of digital recording and the fact that more and more material remains in the digital domain from start to finish have raised demands on preamplifiers. The GainStation 8 is predestined to act as a premium recording front end, ensuring that signals of all kinds are preamplified with the highest quality, whether as an alternative to existing console preamps or as a stand-alone solution between source and A/D converter.

The quality of your recordings has a major influence on the subsequent mixing process – good recordings require less processing in later stages. Improved transparence and understandability can be achieved with less equalization and compression if the signals are recorded optimally, often allowing individual signals to be mixed at lower levels without compromising their presence.

The GainStation 8 can also effectively improve live recordings and mixes. Particularly in live situations, microphone signals must often travel extremely long distances to reach the FOH or mobile console, resulting in high cable capacities, which can degrade and color the sound. In this application, we recommend placing the GainStation 8 on stage. This allows for short cable runs to the preamps, whereas the GainStation's gain structure and fast output stages can easily drive the longer runs that ensue.

The following section, while not attempting to represent a complete guide or answer all questions, provides several operational tips for various instruments.

Inside the GainStation8
The most time-consuming part of the development of the GainStation8 was searching for, selecting and matching components, PCB‘s and IC‘s. One decisive factor in achieving impeccable audio quality is the refusal to accept any weak spots in the chain—the insistence upon each link being as good as the next. It makes no sense to use a world-class op-amp with an improperly engineered power supply or lower-quality passive components such as standard resistors and condensers.

The GainStation8 is based on fully discrete op-amps that operate in class A mode. Class A operation dictates that both end transistors are constantly conducting current to prevent distortion. In conventional class B amplifiers, each transistor carries a half-wave, and distortion occurs every time current moves from one transistor to the next. Class A operation requires much higher closed-circuit current—approximately 6mA with this op-amps or roughly three times the total current consumption of a conventional amplifier—which in turn leads to increased heat generation.

Several months went into the development of the GainStation8 op-amp. First, we tested several different circuit configurations, using test equipment as well as listening tests with a wide variety of program material. It became more and more apparent that less complicated circuits provided better audio results.

The GainStation8‘s input differential amplifier utilizes an extremely low-tolerance, thermal-coupled matched transistor pair in a single casing. This prevents deviances between the transistors to ensure minimal THD (total harmonic distortion) even at various temperatures. The resistors in the initial differential amplifier are connected to a secondary differential amplifier—also based on a matched transistor pair—that handles current conversion.

An output stage, which also operates in class A mode with over 6mA of closed-circuit current, functions as a current amplifier. The transistors and resistors utilized also had an enormous effect on the audio quality. To facilitate selection, we assembled several models and subjected them to extensive listening tests. All this trouble more than paid off: the final GainStation8 op-amp has a slew rate of over 100V/µs—several times faster than industrial op-amps. This is an absolute prerequisite for clean, transparent and dynamic audio. Transients are depicted with unparalleled accuracy, resulting in an open, airy and realistic sound.

The clean stage is based on a fully discrete, balanced instrument amplifier and also operates in class A mode. The special circuit configuration ensures consistent frequency response at virtually every gain setting. With its slew rate of over 200V/µs, it is able to amplify fast transients and extremely high frequencies with almost no distortion. An op-amp subsequently converts the instrument amplifier‘s output signal into an unbalanced signal, which is fed to the tube.
The tube type—a Sovtek® 12 AX7 LPS—was also selected after extensive measurements and listening tests. This tube type delivers an open, transparent sound, excellent noise values and is especially reliable. A generously proportioned 2.2µF WIMA-MKP decoupling capacitor is utilized to ensure clean, punchy low frequency response. An impedance converter adapts the tube‘s high-impedance signal to the output stage, which also utilizes fully discrete op-amps and can easily drive extreme cable lengths.

Coupling condensers were used as sparingly as possible to avoid their inherent disadvantages such as diffuse sound, slurring and loss of dynamics. Instead, servo circuits were utilized to eliminate DC artifacts.

The Instrument Input is a fully discrete impedance converter that also operates in class A mode. It is based on a low-noise field effect transistor that is especially well suited to this task due to its extremely high input impedance. The signal then passes to the clean gain stage.

In order to ensure the shortest possible signal paths, all switching functions are handled by optimally positioned, encapsulated, gas-filled relays with gold-plated contacts—the switches themselves only trigger the relays. Since resistors also greatly affect audio quality, the entire audio signal path utilizes painstakingly selected resistors with 0.1% tolerance.
The op-amp circuits use premium FKP foil condensers, which sound much more open than ceramic types and provide more natural dynamic response.

All circuit boards have oversized grounding surfaces for optimal shielding.