Integrated amplifiers — T+A PA 3100 HV

Within the HV range of T+A in Herford, Germany, the PA 3100 HV fills the integrated amplifier role. It is a fully discrete class AB design that uses the company's high-voltage technology, and it can be expanded with the PS 3000 HV supplementary power supply, phono modules and an analogue signal processor.

Key specs that matter

Rated output is 300 W per channel into 8 ohms and 500 W into 4 ohms, with peak figures of 380 W and 700 W. There are seven RCA line inputs and four balanced XLR inputs, with input impedances of 20 kOhm on RCA and 5 kOhm on XLR, and the RCA inputs are rated at 250 mV. Two pairs of speaker terminals allow A, B or A plus B operation for bi-wiring. Pre-outs are provided on RCA, at 1 V nominal and 9.5 V maximum, and on XLR, at 1.45 V nominal and 19.6 V maximum, and a headphone socket has a 50 ohm source impedance. Its published frequency response is 0.5 Hz to 180 kHz at minus 3 dB, a power bandwidth of 1 Hz to 150 kHz, THD below 0.03%, a signal-to-noise ratio above 115 dB, a damping factor above 65 and a slew rate of 60 V per microsecond. The chassis measures 17 x 46 x 46 cm and weighs 38 kg.

Engineering and use context

The PA 3100 HV starts with a differential cascode amplifier with individually selected audio J-FET transistors, and every stage is built from discrete parts without op-amps, with almost no negative feedback. HV technology lets the circuits handle signals up to 60 V peak to peak without distortion. Inputs are switched by encapsulated, gas-tight relays with gold contacts, and the preamplifier uses bi-stable relays that need no permanent coil current. Volume is set by a network of discrete precision resistors switched by gold-contact relays. The power supply holds 120,000 microfarads of reservoir capacity, and in standby it consumes less than 0.5 W. The optional PS 3000 HV adds 1,800 W of supply power. Plug-in phono modules cover MM or MC cartridges, and the APM module adds tone and loudness functions. Further options include a trigger input, surround pass-through and a LAN connector, and the F3001 infrared remote is supplied.

Pairing

The balanced inputs and XLR pre-out suit fully balanced sources and additional power amplifiers, while the dual speaker terminals support bi-wired loudspeakers. The unit can be ordered for 110 V at 60 Hz or 220 to 240 V at 50 Hz.

Alternatives

T+A's Symphonia is a smaller integrated amplifier that adds an in-built DAC, network streamer and tuners to Purifi-based class D amplification.