T+A A 3000 HV Stereo Power Amplifier

Case Compartment

The entire electronic power circuit with output stages and mains power supply is housed in its own shielded compartment in the underside of the machine. The dividing wall between top and bottom sections is 10 mm thick and – of course – is also made of aluminium. Voltage amplification and current amplification circuitry is housed on separate circuit boards in separate case sections, in order to prevent mutual interaction. The sophistication of the design does not stop there, as we have even provided galvanic separation between the two. Thanks to this uncompromising design philosophy there is absolutely no feedback of the loudspeaker currents into the voltage amplifier stages, and complete freedom from loudspeaker loading effects.

Amplifier Section

The voltage amplifier is an extremely linear, broad-band, cross-coupled differential cascode amplifier, followed by a single-ended Class A large signal stage which provides superb sound quality. The fully symmetrical current amplifier stage (output stage) is fitted with MOSFET drivers and the latest “thermal tracking” bi-polar output transistors; this combination delivers a very harmonious audiophile sound image combined with tremendous current delivery capacity. The output stage transistors feature integral temperature monitor diodes which we use to maintain the power transistors at an absolutely constant operating point, regardless of temperature, allowing us to control the circuit’s distortion behavior perfectly, regardless of the momentary load. By maintaining full symmetry in the arrangement of all conductors in the output stages, speaker cables and mains power supply we have succeeded in providing complete compensation for all signal currents. The net result is a complete lack of magnetic stray fields, and no electromagnetic feedback into the input stages.

Speaker Terminals

The enormous power of the power amplifier calls for particularly high-quality, stable loudspeaker terminals; they are machined from solid pure brass and rhodium-plated on every surface. Rhodium is the perfect contact material: as conductive as silver, as durable as platinum, as corrosion-resistant as gold (and unfortunately as expensive as all three put together). For the most exacting requirements a further option exists for improving the quality of the voltage and current supply: this is the PS 3000 HV supplementary mains unit.