T+A's HV Series represents the pinnacle of solid-state performance. Shown here, the A 3100 HV power amp.
"Any music lover would be blessed to have this amplifier in their system."
Power amps are often thought of as the heavy muscle in a system, but that overlooks the fact that they also need to be keen, highly attuned diplomats. Loudspeakers, let's face it, are difficult to deal with. They are willful, flighty, and often deceptive. The best you can say about their impedance, for example, is that it is "nominal" because it varies wildly depending on frequency. And the specs can be non-intuitive: A highly sensitive speaker that often drops below 2 ohms can be much harder to drive than one with low sensitivity but a steady near-8-ohm impedance curve. Most challenging, they have moving parts. Woofer cones need to be swiftly kicked into motion, and then made to stop or turn, not on a dime, but on a hair-width.
It's the power amp that's doing all of this negotiating, problem-solving, and heavy lifting. So, if you have loudspeakers you love, a power amp is a crucial choice in your search for perfect voicing.
Jason Victor Serinus definitely understands the centrality of a power amp. In his Equipment Report for the November 2026 issue of Stereophile, he covers the T+A Elektroakustik A 3100 HV power amp in great detail. The A 3100 is an 84-lb. dual-mono heavyweight with a 1,000-W toroidal transformer that delivers up to 75 W of pure class-A power in High Current mode and 500 W in High Power mode. It can be monoblocked to deliver 380 W and 650 W, respectively.
Finding a Higher Voltage
In his review, Jason talks to T+A's founder, Siegfried "Siggi" Amft, about the beginnings of Siggi's loudspeaker brand, which branched into electronics in 1988.
Siggi loved the sound of tubes but struggled with their "reliability, stability, and endurance." One of the reasons tubes sound so good, Siggi realized, is that they operate in the hundreds of volts compared with a standard solid-state op-amp-based circuit's ±15 V.
So Siggi set out to create a discrete solid-state power amp circuit that operated at 350 V. This is up there with tube amps, which operate at approximately 300–600 V internally. This high voltage provides ample headroom over the ±12 V required for the music signal. Also, linearity is greatly improved because circuit designers have a large operating range for transistors and can use only the most linear portions of the components' behavior.
The A 3100 HV has a 1,000 W toroidal transformer and the amp operates in class-A or class-AB modes.
Theorie und Anwendung
In German, T+A stands for Theorie und Anwendung, which means Theory and Application. The naughty implications of T and A for English-speaking ears notwithstanding, it's a fairly dry name that simply doesn't convey the degree to which T+A products connect you with the music.
Ash N., our product manager, has known T+A HV for many years, and with this new model, he's the most excited about the High Current mode that offers pure class-A operation. "This gives you a taste of the M 40 HV [T+A's hybrid monoblock flagships], which are much more expensive."
If you have demanding speakers, says Ash, you can switch to the High Power (class-AB) mode. You can also run the A 3100 HV as monoblocks, and in the most exacting situations with the biggest rooms and the most difficult speakers, you can even add the PS 3100 HV external power supply.
Jason agrees, writing in his review, "This amplifier’s considerable glory lies in class-A. In High Current mode, its musicality competes with some of the finest amps I’ve auditioned, many of which cost far more. Any music lover would be blessed to have this amplifier in their system. The A 3100 HV is a stellar musical achievement."
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