In the ingenious overall circuit design of the HV (= High Voltage) series – developed in-house by T+A – all the amplifier stages operate at much higher operating voltages than usual: in the pre-amplifier the figure is 100 Volt, in the output stages 360 Volt. In a similar manner to valve amplifiers, the actual modulation of all the stages can be kept very low. Only a very small section (less than 20%) of the performance graph of the amplifier transistors is used, thereby virtually eliminating the curvature (non-linearity) of that characteristic. Additional measures for improving the linear nature of the voltage amplifier stages are also employed. In addition to outstanding linearity, the high operating voltages employed offer the advantage of extremely wide dynamic range. We have developed this unique technology for use in all the HV-series machines, since the tremendous sonic improvements which it makes possible can be exploited in the output stages of source devices such as the MP 3000 HV multi-source player as well as in pre-amplifiers and power amplifiers.
The back panel shows the P 3000 HV’s symmetrical double-mono construction. The channels are maintained consistently separate. The pre-amplifier circuit boards are of symmetrical construction, and are located under the case top cover; this layout eliminates electro-magnetic influences. They are housed in their own compartment made of thick-walled (10 to 15 mm) aluminium plates, and are completely separated and shielded from the mains unit and power supply in the bottom section of the case. The circuit topology is based on a cascode differential amplifier with individually selected audio J-FET transistors, and stages of completely discrete construction without op-amps (operational amplifiers). Their linear nature is not derived from “hard” negative feedback, as in the case of standard op-amps, but from the quality of the circuit topology and the components employed, which are carefully selected and adjusted. For this reason virtually no overall negative feedback is required. T+A HV technology enables signals up to 80 Vss to be processed without distortion – a value which is unique for a transistor amplifier. Show more