T+A AMP 8 Power Amplifier
The AMP 8
In order to take full advantage of the enormous sound quality of the DAC 8 DSD, an extremely good amplifier is required, which is uncompromisingly constructed and equipped. This is why the AMP 8 is based on the circuit and design technology of our HV and R-series amplifiers. The design is fully symmetrical and the output stages are equipped with high-performance ThermalTrakTM audio transistors. A cleverly programmed mikro-processor monitors the AMP 8 and controls the protection circuit, which switches of the output relay in case of a short circuit, overheat and overload.
One must not be deceived by the small housing size, the AMP 8 can deliver due to its extremely stable power supply more than 100 watts of continuous output power in the highest quality. The slow-running cooling fan is silent, and is controlled by the micro-processor according to load and temperature. The AMP 8 sounds sensational: vigorous, dynamic, high-resolution yet delicate, subtle and audiophile. The combination of DAC 8 and AMP 8 sets new standards far beyond its price class.
The overall circuit design of the AMP 8 is that of our sensational PA 3000 HV integrated amplifier, which is why the input stage and the voltage amplifier stage operate at much higher voltage potentials (HV – High Voltage concept). The input stage is a cross-coupled J-FET cascode amplifier, while the voltage amplifier stage is a single-ended Class-A Hawksford FET cascode. The output stage is responsible for current amplification, and is equipped with ThermalTrak TM high-performance audio transistors to ensure that the bias point is totally stable and free of inertia effects. The voltage amplifier stage and the current amplifier stage are completely separate from each other, and each has its own power supply. This prevents any feedback effects from the loudspeakers influencing the voltage amplifiers, which are crucial to sound quality. We call this circuit concept ICA (Isolated Current Amplifier), and developed it years ago for our R-series of equipment. The individual stages are of extremely linear, broad-band design, with the result that the AMP 8 requires very low levels of “overall” negative feedback; the bandwidth is more than 200 kHz. Our engineers have invested tremendous effort in creating a circuit track layout with absolutely minimal inductivity, thereby helping to achieve superb transient and dynamic response.
At those points in the circuit which are crucial to sound quality we employ carefully selected audiophile components such as amagnetic Vishay resistors and special WIMA and ELNA audio capacitors.
The mains power supply is designed to cope with extremely severe and difficult loads. Its torroidal transformer generates up to 400 Watts whilst maintaining low leakage fields, and is capable of driving even very demanding loudspeakers effortlessly. The power supplies for the amplifier stages are completely separate for each channel, and feature their own reservoir capacity and buffering. In consequence there is no trace of interaction of any kind between the channels.