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T+A HV electronics with Magico loudspeakers in the Small Room

The T+A story

Theory and application: high-voltage electronics, in-house converters and transports, built in Herford since 1978.

Founded 1978 in Herford, East Westphalia, Germany, where every T+A is still designed and built by Siegfried Amft · ta-hifi.de

The history and technologies of T+A elektroakustik of Herford, Germany, and what Pearl Audio keeps on the floor.

Siegfried Amft studied physics at the Technical University of Hannover in the 1970s and intended a career in plasma-physics research; lectures on electroacoustics by Fritz Sennheiser turned him toward audio, and after his final exams he founded T+A in Herford, in East Westphalia, in 1978. The name stands for Theorie und Anwendung, theory and application. Banks were reluctant to finance a young scientist, and money was scarce. The company began in professional sound reinforcement; its first commercially sold product was the omnidirectional Delta loudspeaker series. In 1982 came the transmission-line loudspeakers that T+A still builds under the Criterion name, with a folded multi-resonator line loading the woofers instead of a reflex port, together with research into applying control engineering to loudspeakers; that year Lothar Wiemann, who had joined as a student, developed the company's first electronic components and active loudspeakers. The Solitaire OEC of 1984 and 1985 was a fully active loudspeaker with patented opto-electronic sensors reading the position of the diaphragm, electrostatic drivers and direct-coupled high-voltage tube amplifiers. The first stand-alone preamplifiers and power amplifiers appeared in 1986 under the Pulsar name.

In 1988 T+A set up a research and development division of five engineers to design complete electronics lines, moved into its own buildings, and introduced AudioCon, its first full electronics line and one of the first consumer systems to network its components over a bus under one remote control. By 1992 electronics earned more than loudspeakers, and the Pulsar electronics evolved into the R series, introduced that year; the late-1990s A 1530 R power amplifier had no source selection, no displays and no digital interfaces. The Solitaire A2D of 1995 was billed as the first fully digitally controlled active loudspeaker on the market. Quartet Marketing Group brought the brand to the United States from 2002 to 2008. A new administration, sales and laboratory building was completed in 2003, and the company had about 100 employees in 2005. The V 10 tube integrated amplifier won the EISA High-End Audio award for 2004–2005 and was reviewed in Stereophile in 2004. In 2008 T+A sold more than 8,000 loudspeakers and about as many pieces of electronics, and introduced the first Caruso all-in-one system.

T+A shipping crates stacked after a delivery to Pearl Audio, April 2024
T+A crates after a delivery, April 2024. Photo: Pearl Audio.

The High Voltage series took three years to develop. Amft dates its introduction to 2012; T+A's own account says it first appeared in 2013, and the MP 3000 HV and PA 3000 HV won the EISA High-End Audio award for 2013–2014. The idea was to run transistor voltage-gain stages at supply voltages several times higher than usual, so that each device works over a small, linear part of its curve as a tube does, with virtually no overall negative feedback. The Absolute Sound named the PA 3000 HV its Product of the Year in 2017. The PA 2000 R integrated amplifier and G 2000 R turntable arrived in 2015, as did the PDP 3000 HV SACD player and converter. The DAC 8 DSD of the same period introduced T+A's separate converters for PCM and DSD: Wiemann had found it very difficult to preserve a true DSD signal path with ready-made chips, so T+A built its own one-bit converter and wrote its own Bézier oversampling filters. The PA 3100 HV, with VU meters and a DC-coupled preamplifier section, was reviewed in early 2017; by then Stereophile was listing Rutherford Audio of Centennial, Colorado as the US distributor.

T+A HV series electronics with Magico loudspeakers in the Small Room at Pearl Audio, October 2025
T+A HV electronics with Magico in our Small Room, October 2025. Photo: Pearl Audio.

For the company's fortieth anniversary in 2018 T+A launched the M 40 HV, a hybrid mono amplifier with 6SN7 triodes at its input, as an Anniversary Edition that stayed in production because of demand; Conradin Amft, the founder's son, joined the company the same year. On March 8, 2019 T+A announced the SD 3100 HV and SDV 3100 HV converters and the PDT 3100 HV transport, with an SACD mechanism developed from the ground up and DSD processed to DSD 1024, which T+A calls the world's first DSD 1024-capable player; The Absolute Sound named the SDV and PDT its Products of the Year. In March 2020 the Solitaire P planar-magnetic headphones and the HA 200 headphone amplifier opened a new category, and the P 3100 HV preamplifier followed on May 21, 2020 at $19,500. Conradin Amft became global marketing head in February 2020. In August 2021 the company set up T+A North America Inc. in St. Marys, Georgia. The Series 200, the DAC 200, A 200 and MP 200, was announced on September 17, 2021, the converter inheriting the SDV 3100 HV's design and the amplifier pairing PURIFI Eigentakt output stages with T+A's HV voltage stage.

Lothar Wiemann, chief developer of electronics for 39 years, handed over to Jörg Küpper around 2022, while Siegfried Amft remained managing director responsible for loudspeakers. The Solitaire T wireless headphones were shown at Munich High End in May 2022, and the Solitaire S 540 loudspeaker debuted at AXPONA 2023. The R 2500 R receiver won the EISA Premium All-in-One award for 2024–2025, and in the autumn of 2024 T+A rolled out ASA G3, the third generation of its in-house streaming architecture, across the MP 2000 R G3, MP 2500 R G3, MP 3100 HV G3 and MP 200 G3, with factory upgrades offered for earlier units. On May 6, 2025 FIDELITY reported that Siegfried Amft was transferring his shares to his son: Conradin Amft, who had built the headphone range and founded the US subsidiary, became CEO, with his father remaining a managing director and the company family-owned. That spring a factory visit counted about 90 employees, 14 of them in research and development, with about 95 percent of production in Herford and surface-mount board assembly placed with a specialist using T+A-supplied parts. The PSD 3100 HV streaming preamplifier and the Symphonia streaming integrated followed in 2025.

T+A HV series electronics on a rack at Pearl Audio, January 2025
HV series electronics on the rack, January 2025. Photo: Pearl Audio.

At AXPONA in April 2026 T+A showed the A 3100 HV power amplifier, successor to the A 3000 HV, and the SDX 3100 HV, which replaces the SDV 3100 HV as the reference streaming converter and preamplifier; both launched officially on July 11–13, 2026, and the PS 3100 HV external power supply was unveiled on September 3, 2026, with a 1,200 VA transformer and 240,000 µF of storage for the A 3100 HV. Herb Reichert reviewed the MP 3100 HV G3 in Stereophile on June 5, 2026 and called it CD playback at its highest imaginable level. Forty-eight years after its founding T+A is still a family company managed by its proprietors, with a team of fifteen designers and developers and seven service technicians in Herford, every unit measured before it leaves, and more than 98 percent of devices of any age returned to working order when they come back for service. Its products are sold in roughly 30 countries; in the United States T+A North America handles distribution and service support. Amft's rule for the company has not changed: a well-designed unit has to have good parameters over all, not only one extremely good one.

Milestones

  1. 1978 Founded in Herford Siegfried Amft, a physicist steered toward audio by Fritz Sennheiser's lectures on electroacoustics, founds T+A, Theorie und Anwendung, in Herford. It begins in professional sound reinforcement; the omnidirectional Delta loudspeakers are its first commercial product.
  2. 1982 Transmission lines and the first electronics The multi-resonator transmission-line loudspeakers that became the Criterion line, and research into control engineering for loudspeakers. Lothar Wiemann, who joined as a student, develops the first electronic components and active loudspeakers.
  3. 1984 Solitaire OEC A fully active loudspeaker with patented opto-electronic diaphragm-position sensors, electrostatic drivers and direct-coupled high-voltage tube amplifiers; the Solitaire A2D of 1995 follows as the first fully digitally controlled active loudspeaker.
  4. 1986 Pulsar and AudioCon The first stand-alone preamplifiers and power amplifiers under the Pulsar name. In 1988 a five-engineer R&D division, the company's own buildings, and AudioCon, one of the first consumer lines to network its components over a bus under one remote.
  5. 1992 The R series Electronics now earn more than loudspeakers, and the Pulsar electronics evolve into the R series. The late-1990s A 1530 R power amplifier has no source selection, no displays and no digital interfaces.T+A PA 2500 R Integrated Amplifier
  6. 2004 V 10 and the first Caruso The V 10 tube integrated wins the EISA High-End Audio award for 2004–2005. Quartet Marketing Group imports the brand to the US from 2002 to 2008; the first Caruso all-in-one arrives in 2008.T+A Caruso All-in-One Music System
  7. 2013 The High Voltage series After three years of development, shown by Amft's account in 2012 and on sale in 2013: transistor gain stages on rails several times higher than usual, with virtually no overall feedback. The MP 3000 HV and PA 3000 HV win the EISA High-End Audio award for 2013–2014.T+A PA 3100 HV Integrated Amplifier
  8. 2015 Separate PCM and DSD converters The DAC 8 DSD pairs eight Burr-Brown converters for PCM with T+A's own one-bit DSD converter and Bézier filters. The PA 2000 R, G 2000 R turntable and PDP 3000 HV arrive the same year.T+A PA 2000 R Integrated Amplifier
  9. 2018 M 40 HV, the fortieth year A hybrid mono amplifier with 6SN7 triodes at its input, class A to 60 W and 550 W into 8 ohms, launched as an Anniversary Edition and kept in production by demand. Conradin Amft joins the company.T+A M 40 HV Hybrid Mono Power Amplifiers (pair)
  10. 2019 PDT 3100 HV and the 3100 converters Announced March 8, 2019: the SD and SDV 3100 HV, with DSD processed to DSD 1024, and the PDT 3100 HV transport with a mechanism, decoder and servo developed from the ground up. The Absolute Sound's Products of the Year.T+A PDT 3100 HV CD/SACD Transport
  11. 2020 Solitaire P, HA 200 and P 3100 HV In March the first T+A headphones, around the in-house TPM 3100 planar transducer, with the HA 200 class-A amplifier; on May 21, 2020 the DC-coupled P 3100 HV preamplifier at $19,500.T+A Solitaire P
  12. 2021 T+A North America and the Series 200 In August the company sets up its own US subsidiary in St. Marys, Georgia. On September 17, 2021 the DAC 200, A 200 and MP 200 are announced; the Solitaire P-SE wins an EISA Award.T+A DAC 200 DAC / Preamplifier
  13. 2024 ASA G3 and the R 2500 R The third generation of T+A's in-house streaming architecture reaches the MP 2000 R G3, MP 2500 R G3, MP 3100 HV G3 and MP 200 G3, with factory upgrades for earlier units. The R 2500 R wins the EISA Premium All-in-One award.T+A MP 3100 HV G3 SACD Player / Streaming DAC
  14. 2025 Conradin Amft becomes CEO On May 6, 2025 the founder transfers his shares to his son; Siegfried Amft stays on as managing director and the company remains family-owned. The PSD 3100 HV and the Symphonia arrive.T+A PSD 3100 HV Streaming DAC / Preamplifier
  15. 2026 A 3100 HV, SDX 3100 HV and PS 3100 HV Shown at AXPONA in April and launched July 11–13, 2026: the A 3100 HV succeeds the A 3000 HV and the SDX 3100 HV replaces the SDV 3100 HV. The PS 3100 HV supply follows on September 3, 2026.

T+A at Pearl Audio

Pearl Audio is an authorized T+A dealer in Portland. We put T+A together as systems, from a Series 200 or Symphonia setup to an HV stack built around the PDT 3100 HV, the PSD 3100 HV and the P 3100 HV, and match them to loudspeakers in our rooms and in yours. We configure the streaming, the converter filters, phono modules and the Solitaire headphones with the HA 200, deliver and set up in your home, and arrange in-home comparisons when the choice is between two T+A amplifiers. Service and firmware support run through T+A North America in St. Marys, Georgia.

Signature technologies

The engineering behind T+A

T+A gives its technologies names because each one solves a specific problem. Here is what each does, where it came from, why it matters in a system, and what you may hear.

Transistors run where they are most linearSince 2013

HV: high-voltage amplifier stages

T+A's HV circuits run their transistor voltage-gain stages on supply rails several times higher than ordinary solid-state designs, up to 100 V in the P 3100 HV preamplifier and up to 500 V in the M 40 HV's power stages. Each device then works over a small, linear part of its curve, as a tube does, so the circuit needs virtually no overall negative feedback. Read the deep diveClose

What it does

Most solid-state audio circuits run on low rails; Alan Sircom notes that most modern circuits run at about plus and minus 5 V. The High Voltage series, three years in development and introduced in 2012 by Siegfried Amft's account or 2013 by T+A's own, moved the voltage-gain stages to rails several times higher, with the stated aim of combining the sonic and technical advantages of tubes and transistors while avoiding the inherent disadvantages of present-day valves. In the PA 3100 HV the input is a differential cascode amplifier of individually selected audio J-FET transistors that can process signals up to 60 V peak-to-peak without distortion; the P 3100 HV runs at up to 100 V and handles 80 V peak-to-peak; the M 40 HV's power stages reach 500 V, behind a class-A input stage of 6SN7 triodes. Because each transistor works over a small, linear part of its curve, the circuit needs virtually no overall negative feedback, and bandwidth and headroom are wide: the P 3100 HV is specified from 0.5 Hz to 300 kHz. HV is used in the amplifier stages of every HV-series component, the same voltage-gain stage appears in the Series 200, the HA 200 and the Symphonia, and the PA 2500 R and PA 2000 R carry a high-voltage dual-mono design on the R-series chassis.

Why it matters in a system

An amplifier stage that stays linear without heavy feedback behaves the same from the first watt to clipping and into awkward loudspeaker loads, which is what HV owners describe as ease at volume. It is also the reason a T+A preamplifier, converter and power amplifier sound of a piece: the same voltage-gain stage sits in all of them, from the DAC 200 to the M 40 HV.

What you may hear

Jason Victor Serinus, reviewing the PA 3100 HV for Stereophile, found the midrange strong, exceptionally smooth, and all of one piece. Alan Sircom in hi-fi+ called the SDV 3100 HV extremely listenable, with extraordinary clarity and dynamics, and musically inviting.

PCM and DSD never meetSince 2015

Two converters: Quadruple PCM and True 1-bit DSD

Instead of converting DSD to PCM inside one chip, every current T+A converter carries two. PCM goes to eight 32-bit Burr-Brown sigma-delta chips, four per channel in a double-differential arrangement; DSD goes to a discrete one-bit converter of T+A's own design that never touches PCM, and relays switch between the two paths. Read the deep diveClose

What it does

T+A's converter layout dates from the DAC 8 DSD of about 2015, when Lothar Wiemann concluded that it was very difficult to preserve a true DSD signal path with ready-made chips. The PCM side is the Double-Differential-Quadruple-Converter: four 32-bit Burr-Brown sigma-delta converters per channel, run in conversion-only mode with T+A's own upsampling and filtering ahead of them, an arrangement T+A says lowers noise by 6 dB. The MP 3100 HV G3 feeds them at 352.8 or 384 kHz; the DAC 200 and PSD 3100 HV accept PCM to 768 kHz. The DSD side is the T+A True-1Bit converter, a discrete circuit that takes the native bitstream and oversamples it; T+A holds that DSD's advantages appear only when the signal is massively oversampled, and the reference converter upsamples DSD by 32 times. The DAC 200, HA 200 and SDX 3100 HV decode up to DSD 1024, or 49.2 MHz, a capability T+A introduced in the SD and SDV 3100 HV of March 2019 and calls the world's first DSD 1024-capable player; the PSD 3100 HV, MP 3100 HV G3, MP 2500 R G3, R 2500 R and Symphonia are specified to DSD 512. In 2026 T+A gave the arrangement a name, Path Separation Technology. The Symphonia uses a two-chip-per-channel Double Differential derivative of the PCM converter.

Why it matters in a system

A chip that handles DSD by first turning it into PCM, or the reverse, imposes one filter's character on both formats. Giving each its own converter means an SACD or a DSD file reaches the analog stage as the bitstream it was recorded as, and a PCM file is handled by a converter built for multi-bit data with T+A's own filters in front of it.

What you may hear

Herb Reichert, reviewing the MP 3100 HV G3 for Stereophile, wrote that the T+A's smooth, nuanced sigma-delta feels considerably different than dCS's liquidy FPGA-controlled Ring DAC, and called it CD playback at its highest imaginable level. Jim Austin heard treble that glistened, with no digital glare.

Four filters, no ringing, the listener's choiceSince 2015

Bézier oversampling filters and 56-bit DSP

T+A writes its own PCM oversampling in a signal processor instead of using the filters built into the converter chips: two FIR filters and two Bézier-polynomial filters, plus a non-oversampling mode, selectable by the owner. The Bézier filters avoid the pre- and post-ringing of conventional filters, and a third-order Bessel analog filter follows, switchable between 60 and 120 kHz. Read the deep diveClose

What it does

Every oversampling converter interpolates new samples between the ones on the disc or in the file, and the filter that does it leaves a signature; conventional linear-phase FIR filters ring before and after each transient. In the DAC 8 DSD T+A moved this work out of the converter chip and into a 56-bit signal processor running its own algorithms, and the current units offer five settings: FIR short, FIR long, Bézier/IIR, Bézier and NOS, or non-oversampling. Lothar Wiemann's point about the Bézier interpolation is that it has no pre-ringing and no post-ringing. In the reference converters a 16-times Bézier-polynomial filter takes 44.1 and 88.2 kHz material to 705.6 kHz and 48, 96 and 192 kHz material to 768 kHz before the Quadruple converter sees it. After conversion a phase-linear third-order Bessel filter, switchable between a 60 and a 120 kHz cut-off, removes what remains above the audio band without adding ringing of its own. The same processor and filter set run in the DAC 200 and HA 200, the MP 2000 R G3 and MP 2500 R G3, the R 2500 R, the PSD 3100 HV, the MP 3100 HV G3 and the SDX 3100 HV, so the choice an owner makes on a Series 200 converter is the same one offered on the reference.

Why it matters in a system

The reconstruction filter determines how a converter handles the leading edge of every note, and the ringing of a steep filter is one reason digital playback can sound hard. Letting the listener choose among FIR, Bézier and no oversampling, with an analog filter gentle enough to add nothing of its own, means the converter can be matched to the recording and to the rest of the system.

What you may hear

Jim Austin, in Stereophile on the MP 3100 HV: treble tones glisten like light reflected from the facets of a diamond, and also seem especially relaxed, with no digital glare. Craig Joyce at StereoNET called the DAC 200 a standout product that handles a wide range of music with clarity and precision.

Two mains inlets, isolated data, one clockSince 2020

Digital-analog separation and the De-Jitter Masterclock

In T+A's converters the digital and analog sections have their own power supplies and, in the HV components, their own IEC mains inlets; data crossing between them passes through ultra-fast digital isolators, so switching noise cannot reach the analog output. Incoming digital signals are reclocked in two stages against a quartz master clock before they reach the converter. Read the deep diveClose

What it does

A converter's analog output is only as quiet as the ground it shares with its digital logic. T+A's answer, which it calls the Digital Analogue Separation System in the DAC 200, is to keep the two halves apart electrically: the analog and digital mains sections are galvanically separated, each with its own transformer, and the signal and control lines between them run through ultra-fast digital isolators from Silicon Labs, with the clocks isolated as well. The HV components go further and fit two IEC inlets, so the MP 3100 HV G3 draws its digital and analog power through separate cords, and the P 3100 HV, a purely analog preamplifier, gives each channel its own inlet. The timing side is the De-Jitter Masterclock: an incoming signal first passes a phase-locked loop, then a microprocessor checks it and switches to a quartz master clock; when the signal fails T+A's criteria a second stage, the Second Jitterbug, engages and cuts residual jitter by a factor of four. The SDX 3100 HV uses two femto-second crystal oscillators feeding a multi-stage jitter-cleansing system. James Shannon of T+A says the separate AC inputs make it virtually impossible to see any kind of digital noise entering the analog output.

Why it matters in a system

Noise that leaks from a streaming board or a USB receiver into the analog stage does not sound like hiss; it sounds like a loss of depth and a hardening of the treble that is easy to blame on the recording. Isolation and reclocking are what let a T+A converter accept a laptop or a network stream and sound as quiet as it does from its own disc drive.

What you may hear

Stereophile on the R 2500 R: its DAC is in keeping with the very best modern DACs in that it is ultra-revealing and transparent, and the component doesn't call attention to itself in any way. Craig Joyce at StereoNET gave the DAC 200 a 9 out of 10 and an Applause Award.

A disc mechanism machined in Herford, not bought inSince 2019

In-house SACD transport and IPA Link

T+A builds its own disc transport: a linear-tracking laser block riding on two aluminum linear bearings inside a chassis machined from a single block of aluminum, with its own servo board, SACD decoder and control software. DSD leaves the transport as the native bitstream, and the IPA Link carries it, with its clock, to the matching converter. Read the deep diveClose

What it does

Most SACD players use a drive and decoder chipset made for Blu-ray players, and convert the disc's DSD to PCM before it goes anywhere. For the PDT 3100 HV of March 2019 T+A's engineers developed a decoder and drive mechanism from the ground up: a high-precision linear-tracking drive with a double laser, 658 nm for SACD and 790 nm for CD, a high-torque synchronous motor, an anti-resonance weight, a chassis cut from one aluminum block, two aluminum linear bearings, and a drawer that runs on stainless steel rails in PTFE and phosphor-bronze bearings. The servo board, SACD decoder and control software are T+A's own, written to deliver native DSD and PCM rather than converting DSD to PCM first; James Shannon's argument is that less error correction means greater accuracy of the decoding process. The mechanism alone weighs nearly 20 pounds. The High Res IPA Link is a proprietary connection, using low-voltage differential signalling, that transmits PCM and DSD data bit-accurately along with high-precision clocking, a constant bitstream of unchanged raw data, from the PDT 3100 HV to the SD, SDV and SDX 3100 HV. The same drive sits inside the MP 3100 HV G3 and the MP 2500 R G3, while the MP 2000 R G3, MP 200 G3 and R 2500 R use a slot-loading CD drive.

Why it matters in a system

A transport is the one part of a digital system that is still mechanical, and read errors, vibration and the conversion of DSD to PCM all happen before the converter can do anything about them. Owning the mechanism and the decoder lets T+A keep SACD native, and keep the drive in production and in service for as long as the player.

What you may hear

Robert Harley, reviewing the PDT 3100 HV with the SDV 3100 HV for The Absolute Sound, called it by far the smoothest and quietest transport he had encountered, with SACD playback vaulted into another realm. Herb Reichert found the MP 3100 HV G3 CD playback at its highest imaginable level.

Designed, programmed and certified in HerfordSince 2024

ASA G3: the in-house streaming architecture

T+A designs its own streaming hardware and software rather than buying a module. The third-generation Audiophile Streaming Architecture of 2024 is a quad-core board with Wi-Fi 6 and Gigabit Ethernet, native DSD streaming to DSD 256, Tidal, Spotify and Qobuz Connect, AirPlay 2 and Roon Ready, run from T+A's own MusicNavigator G3 app. Read the deep diveClose

What it does

Streaming boards are the part of a player most likely to be obsolete first, and most manufacturers buy them from one of a few suppliers. T+A keeps the whole chain in-house: design, PCB layout, certification, assembly, measurement, operating-system programming and app development. ASA G3 arrived on September 20, 2024 in the MP 2000 R G3 and MP 2500 R G3, in the MP 3100 HV G3 on October 18, 2024, and in the MP 200 G3 on November 28, 2024; Conradin Amft, then chief operating officer, described it as a core technology that the company would gradually implement in new products. The module streams DSD natively from the network for the first time in T+A's history; handles Tidal, Qobuz, Deezer, Amazon Music and HighResAudio, Tidal Connect, Spotify Connect and Qobuz Connect, AirPlay 2 and Roon Ready; and shares its control with the FM and DAB+ tuners the players also carry. The MusicNavigator G3 app is the controller; on the Caruso a seven-inch touchscreen runs T+A's own NavigatorOS instead. Owners of the earlier MP 3100 HV, MP 2000 R MK II, MP 2500 R and MP 200 can have their units upgraded to ASA G3 at the factory. The PSD 3100 HV, SDX 3100 HV, R 2500 R and Symphonia use the same module.

Why it matters in a system

A streamer that the manufacturer wrote itself is one the manufacturer can keep current, and the factory upgrade path shows what that means in practice: an MP 3100 HV bought in 2017 can be brought to the 2024 platform instead of being replaced. It also means the player, the app and the tuner behave as one product rather than as a module inside a box.

What you may hear

Stereophile on the R 2500 R: the app is the ideal interface, and the component just plays music and does it well. Killain Jones at SoundStage! found the R 2500 R effortlessly dynamic and able to produce deep, visceral bass.

No potentiometer, no chip, no coupling capacitorsSince 2020

Relay volume control and the DC-coupled preamplifier

T+A sets volume by switching precision resistors with encapsulated, gas-tight gold-contact relays rather than with a potentiometer or a volume chip, in 1 dB steps on the DAC 200. In the 3100-generation preamplifiers the coupling capacitors between the input stage, the volume control and the output were removed by a board layout that compensates the transistors' temperature drift. Read the deep diveClose

What it does

A volume control is in series with everything, and the usual choices, a carbon or conductive-plastic potentiometer or an integrated-circuit attenuator, each add noise, channel imbalance or a sound of their own. T+A's HV preamplifiers and the DAC 200 instead use a ladder of precision resistors selected by sealed relays with gold contacts, so at every setting the signal passes through fixed resistors and closed metal contacts. The P 3100 HV of May 2020 went a step further. Lothar Wiemann's goal for the 3100 generation was a capacitor-free preamplifier without servo control, in pursuit of what he called black level: more quiet, fewer disturbances, a blacker background. A new and complex board layout compensates for the transistors' temperature coefficients, so the stages from input to output are DC-coupled with no coupling capacitors and remain, in T+A's words, completely voltage and temperature stable. The PA 3100 HV shares the DC-coupled preamplifier section, which along with its VU meters and a redesigned mains section distinguishes it from the PA 3000 HV; the PSD 3100 HV and SDX 3100 HV carry the same class-A discrete HV preamplifier with relay volume; and the PA 2000 R and PA 2500 R use relay volume on the R-series chassis.

Why it matters in a system

A preamplifier's job is to lose nothing, and capacitors and potentiometers are where most of the loss happens: at low volume, where most listening is done, and in the lowest octaves, which coupling capacitors roll off. Relay switching and DC coupling are why the HV preamplifiers are described in terms of silence between the notes rather than any tonal character.

What you may hear

Matthew Clott, reviewing the PSD 3100 HV for The Absolute Sound: it's not a component you evaluate; it's a component you listen to, and highly, highly recommended. Jason Victor Serinus found the PA 3100 HV meticulously engineered and beautifully made.

The first watts in class A, with power in reserveSince 2017

Class-A regions, High Current mode and external supplies

T+A's HV power stages idle in class A for the first tens of watts before passing into class AB: 10 to 20 W in the PA 3100 HV, 20 to 25 W in the PA 2500 R, 60 W in the M 40 HV, and beyond 75 W in the A 3100 HV's High Current mode. The optional PS 3000 HV and PS 3100 HV take over the output stage's power supply through a heavy umbilical. Read the deep diveClose

What it does

A class-AB amplifier biased deep into class A plays most music, most of the time, without its output devices switching off, and keeps the reserve for peaks. The PA 3100 HV delivers 300 W into 8 ohms and 500 W into 4; its VU meters read watts into 4 ohms. The PA 2500 R is, in The Absolute Sound's description, a dual-mono, fully balanced, high-voltage design with a class-AB output stage biased into class A for the first 20 to 25 watts. The M 40 HV runs in class A to 60 W on its way to 550 W into 8 ohms and 1,000 W into 4. The A 3100 HV of 2026 offers two modes: High Power, 500 W of class AB, and High Current, which trades about half the rated power for greater current delivery and extends the true class-A region beyond 75 watts, depending on the speaker load. For the integrated and the stereo amplifier T+A offers a separate supply: the PS 3000 HV provided an extra 1,800 W of supply power, and the PS 3100 HV of September 2026 carries a 1,200 VA transformer and 24 custom capacitors totalling 240,000 µF, up to 1,200 joules; it feeds the output stages while the amplifier's own supply feeds the input and HV stages.

Why it matters in a system

A loudspeaker with a difficult impedance asks an amplifier for current more than for watts, and class-A bias and a stiff supply are what keep the sound unchanged when it does. James Shannon's own description of the external supply is modest: it makes an audible difference with more challenging loads, and it will not change the tonal balance.

What you may hear

Serinus on the PA 3100 HV in Stereophile: an excellent, meticulously engineered, beautifully made integrated amplifier that seems tailor-made for many audiophiles. Hi-Fi News on the M 40 HV: remarkably well-mannered power amps that are not going to make your listening space uncomfortably muggy.

Class D with a high-voltage gain stage and sine-wave suppliesSince 2021

PURIFI Eigentakt output stages with an HV front end

For its compact amplifiers T+A pairs licensed PURIFI Eigentakt class-D output modules with its own HV voltage-gain stage and a switch-mode power supply that runs a sine-wave clock at more than twice the usual frequency. The A 200 makes 125 W into 8 ohms and 250 W into 4 from a 5 kg chassis, with a damping factor above 800. Read the deep diveClose

What it does

The Series 200 of September 2021 needed HV-series behavior in a chassis 32 cm wide, and T+A's answer was to keep its own circuit where it matters most. The voltage-amplifier stage, the part that sets an amplifier's character, is T+A's HV circuit, which the company describes as unique in the world; the output stage is PURIFI's Eigentakt class-D module. The power supply is T+A's own: a high-frequency sine-wave mains section, described by T+A as a hard supply, whose reservoir capacitors are recharged 100,000 times per second rather than at the mains frequency. The A 200 delivers 125 W into 8 ohms and 250 W into 4; the M 200 mono delivers 210 and 420 W from the same topology; each weighs 5 kg and both are designed around the DAC 200 and HA 200 as a system. The Symphonia of 2025 uses in-house modifications of the Eigentakt technology for 125 W per channel in a retro-styled streaming integrated 38 cm wide with analog VU meters, a phono input and HDMI ARC. The R-series PA 2500 R and R 2500 R keep class-AB output stages but share the HF sine-wave supply, the PA 2500 R carrying two of them with 120,000 µF of storage.

Why it matters in a system

Class D makes it possible to put real power behind a pair of floorstanders in a system the size of a bookshelf, and the objections to it have mostly concerned the input stage and the power supply, which are the two parts T+A kept for itself. The result is a power amplifier that partners the DAC 200 or the HA 200 as a system without a second rack.

What you may hear

John Darko on the Symphonia: an exceedingly competent amplifier that performs on par with similarly priced competition, and a product for tighter spaces and minimalists. Stereophile, quoted by T+A, called it a miniature Meisterstück that delivers more audiophile gravitas than its size suggests.

A driver designed, machined and assembled in HerfordSince 2020

TPM planar-magnetostatic headphone transducers

The Solitaire P headphones are built around T+A's own TPM 3100 transducer, an elliptical 110 by 80 mm planar driver with an ultra-thin, ultra-light film carrying a computed conductor pattern, driven from one side only by shaped neodymium magnets. The Solitaire P-SE uses the TPM 2500 derivative; both are developed and hand-made in Herford. Read the deep diveClose

What it does

T+A entered headphones in March 2020 with the Solitaire P and the HA 200 amplifier, and chose to build the transducer rather than buy one. The TPM 3100 diaphragm is a special ultra-thin film whose conductor pattern is computed to match the magnet geometry; the magnets sit on one side only, so there is no second magnet array between the diaphragm and the ear to reflect and diffract the sound. The Solitaire P is an open design with an impedance of 80 ohms, a response from 5 Hz to 54 kHz, distortion below 0.015 percent at 100 dB and a maximum level above 130 dB; its cups are machined from a 35 mm aluminum plate on a five-axis mill, and it weighs 530 g. The Solitaire P-SE of 2021 carries the TPM 2500, a derivative of the same transducer, at 45 ohms, 8 Hz to 45 kHz and 440 g, with high-damping plastic cups. The closed, wireless Solitaire T of 2022 takes a different route: a 42 mm dynamic driver with a cellulose diaphragm, Bluetooth 5.1, hybrid noise cancelling, about 70 hours of battery and a passive wired mode. The HA 200 was designed as the amplifier for all of them: pure class A with MOS-FET transistors, no op-amps, selectable output impedance and analog crossfeed.

Why it matters in a system

A planar driver's weakness is usually the magnet array in front of it; a single-sided motor removes it, and a transducer made in-house can be matched to its amplifier. With the HA 200's selectable output impedance and class-A current to 700 mA, the headphones and the amplifier were designed as one system rather than as two products.

What you may hear

Herb Reichert, in Stereophile's Gramophone Dreams: materials, finish, and workmanship exceeded anything he had encountered, and the Solitaire P is definitely in the best-of-the-best headphone game. On the Solitaire T, Stereophile found the build quality outstanding.

Theory and application under one roofSince 1978

Designed, built and measured in Herford

Every T+A component is designed, assembled and measured at the company's own buildings in Herford, where it has been since 1988: circuit design, board layout, software, the MusicNavigator app, final assembly and a measurement protocol for every unit. Surface-mount board assembly is placed with a specialist using T+A-supplied parts; about 95 percent of production is in-house. Read the deep diveClose

What it does

T+A has occupied its own buildings in Herford since 1988 and added an administration, sales and laboratory building in 2003. A factory visit in April 2025 counted about 90 employees, 14 of them in research and development; T+A itself describes a team of fifteen designers and developers plus seven service technicians. The scope kept in-house runs from design, PCB layout and certification to assembly, measurement, operating-system programming and app development; the one step placed outside is surface-mount component placement, done by a specialist assembler using components T+A supplies, after which the boards return for final assembly and test. There are no assembly lines or automated placement machines, and nothing leaves the works without a measurement protocol. The company's own description is that it builds acoustic treasures rather than mass products, and it reports returning more than 98 percent of devices of any age to working condition when they come back for service. The engineering continuity is long: Lothar Wiemann, who joined as a student and developed the first electronics in 1982, was chief developer for 39 years before handing over to Jörg Küpper. In the United States, T+A North America in St. Marys, Georgia has handled distribution since August 2021, with service through Pyramid Audio in Austin and Audio Design and Service in Burbank.

Why it matters in a system

A product made in one place by the people who designed it can be supported for as long as its owner wants to keep it, and T+A's factory upgrades, the ASA G3 streaming boards fitted to players from 2017, are the practical form of that. It is also why a T+A system sounds consistent from the Series 200 to the HV line: the same small team designed all of it.

What you may hear

Jim Austin, in Stereophile on the MP 3100 HV: more than any other component he had had in his system, it radiated attention to detail. Michael Manousselis, who imported the brand to North America: they don't leave things to luck or to chance.

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