T+A A 3100 HV Power Amplifier

The A 3100 HV is T+A's reference stereo power amplifier, and it solves a problem most amplifiers duck. Class A sounds the way it does because the output devices never switch off; big power into difficult loudspeakers needs a different design entirely. Rather than compromise between the two, T+A built both into one chassis and let you choose. See the full T+A range we stock.

The HV designation is the same principle that runs through the range — amplifier stages operating at high voltages, which are inherently more linear than conventional circuits before any feedback is applied. In an amplifier of this size that means a 1,000-watt toroidal transformer and 120,000 µF of supply filtering, and it is a large part of why the unit weighs 38 kg.

Two Operating Modes

High Power Mode delivers 300 watts per channel into 8 ohms and 500 watts per channel into 4 ohms, with pulse figures of 380 and 700 watts respectively. Bridged to mono it gives 430 watts into 8 ohms and 800 watts pulse into 4 ohms. This is the mode for loudspeakers with awkward impedance curves or low sensitivity, and for rooms that need filling.

High Current Mode reconfigures the amplifier to run up to 75 watts in pure Class A, or 140 watts in Class AB, in mono only. The wattage drops sharply and that is the point — the quality of the first watt changes character entirely. On efficient loudspeakers in a normal domestic room, 75 Class A watts is a great deal more than most systems ever ask for.

Construction

T+A use what they call Iso-Thermal Geometry to keep the output stage thermally stable, and a Compartment Matrix Design that galvanically isolates the voltage and current stages from one another. Both exist for the same reason: an amplifier this powerful generates heat and interference that will find their way into the signal path unless the layout prevents it.

Power can be stabilised further with the optional PS 3100 HV high-voltage power supply, which feeds the output stages while the internal supply concentrates on the input amplification stages. One caveat worth knowing before you buy: by design, the PS 3100 HV cannot be used in High Current Mode.

Technical Specifications

Who Is It For?

The A 3100 HV suits two buyers who normally have to choose between different amplifiers. If you own loudspeakers that need real current — large floorstanders, panels, anything with a punishing impedance dip — High Power Mode has the reserves. If you own something efficient and want Class A, the same box does that instead.

It partners naturally with the P 3100 HV preamplifier or the PSD 3100 HV if you want streaming and preamplification together. A pair used as monoblocks is the logical end point, and worth discussing before you commit to a single unit — the mode you intend to use changes that decision.

Buying from Martins Hi-Fi

Choosing between High Power and High Current mode is a decision about your loudspeakers, not about the amplifier, and it is much easier made in a demonstration room than on paper. We can talk it through against what you already own, and arrange a listen in Norwich before you commit at this level.

When you get in touch, you'll be speaking with Dave, Chris and Tim at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martins page. We are at 85–91 Ber Street, Norwich, NR1 3EY.