TECHNICAL INFORMATION
The first stage of the NEOX400-210T preamp uses a low noise bi-fet linear scaling amplifier with a 2 pole low cut point at 23 Hz to prevent excessive speaker cone excursion and intermodulation distortion. Additional bandwidth roll-off is provided at 20 kHz for RFI suppression. The variable gain stages are a feedback-divider type control, one of which is all solid state and the other utilizing a cathode follower (tube), each providing a maximum gain of about 30 dB. On the tube stage, variable non-linear loading creates a smooth and natural sounding overdrive rich in harmonics. These foot-switchable and blendable gain stages feed 3 footswitchable, user adjustable signal shaping filters and the 5 band active equalizer. These EQ filters provide over 12 dB of boost and cut, with center position flat. The output amplifier feeds the master volume control and fully protected power amplifier. A low noise differential drive output amplifier is provided for the direct output (switchable pre/ post EQ and ground lift) and is phantom power protected.
The power section consists of a low distortion bipolar power amplifier with integrated limiter which allows gradual overload without sudden loss of feedback control of the speakers. The output is rated at 425 watts RMS at 4 ohms. The amplifier topology is low feedback class A-B with servo control of bias and DC offset.
Also provided is on board output limiting, dual slope integrated VI limiting, solid state thermal protection, short circuit load protection, dc fault protection and RFI suppression. All amplifier status points are indicated on a dual color led array. This amplifier uses heavy duty copper based bi-polar power transistors directly mounted to a fan cooled extruded aluminum heatsink tunnel.
An important and not commonly discussed specification is the power amplifier’s ability to deliver rated power into a reactive load. All speakers present a reactive load to the amplifier, reducing real world driving ability. The power section of the NEOX400-210T amplifier is rated to deliver full power into a reactive load with a 45 degree (leading or lagging) power factor phase angle. This is one important reason Genz Benz amplifiers sound so big.
FRONT PANEL
FEATURES
The following feature set is included on the NEOX400-210T. These features were developed based on usability and are the result of input from veteran players from around the country. It is important for an amplifier to reflect the real needs of the players using them. We feel that this amplifier does just that.
Input — The ¼” input has switchable sensitivity. With the switch in the passive position, the preamp presents a higher gain and input impedance which is tailored to the characteristics of passive pickups. The input impedance of the amplifier’s passive input is set high enough to prevent interaction with the high output impedance of all commonly used passive pickups, including magnetic, piezo-ceramic and piezo film types.
With the switch in the active position, the preamp presents a lower gain and input impedance which is tailored to active pickups. An active pickup is, for all practical discussions, any pickup that uses pre-amplification between the pickup element and the amplifier input. The purpose of this pre-amplifier is to buffer the high impedance signal from the pickup element (magnetic, piezo-ceramic, piezo-film etc) and convert it to a higher level, lower impedance form. It is common for a bass with active pickups to have higher output level and longer sustain because only a small portion of the energy required to make the electrical signal comes from the vibrating string. The majority of the energy comes from an external power source such as a battery. Additional
