T+A HV technology enables signals up to 80 Vss to be processed without distortion – a value which is unique for a transistor preamplifier. For this reason virtually no overall negative feedback is required. 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. All stages are of completely discrete construction with-out op-amps (operational amplifiers). needed to drive the load, so the poweramp, takes the same voltage from the preamp, and adds to it ALL the current, that the preamp. at its output, BUT it cannot deliver the 1mA. The circuit topology is based on a differential cascode amplifier with hand-selected audio J-FET transistors. The power amplifier takes this increased voltage output from the preamp, and sends this to the VERY LOW load impedance, remember the load needs 5V. The circuit boards 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 preamplifier circuit boards are of exact identical construction, and are located under the case top cover this layout eliminates electromagnetic influences. The channels are kept consistently separate. The connector section on the back panel provides impressive evidence of the P 3100 HV’s uncompromising design and symmetrical double-mono construction. 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 3100 HV multi-source player as well as in preamplifiers and power amplifiers. In addition to outstanding linearity, the high operating voltages employed offer the advantage of extremely wide dynamic range. Additional measures for improving the linear nature of the voltage amplifier stages are also employed. For these systems some common sensors are microphones, instrument pickups, and phonographs. The power amplifier provides the higher current necessary to drive loudspeakers. Only a very small percentage (less than 20%) of the possible excursion of the amplifier transistors is used, thereby virtually eliminating the curvature (non-linearity) of that characteristic. The preamplifier provides voltage gain (e.g., from 10 mV to 1 V) but no significant current gain. In a similar manner to valve amplifiers, the actual modulation of all the stages can be kept very low. 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 preamplifier the figure is up to 100 Volt, in the power amplifier up to 360 Volt.
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