Tantal 3C24 amplifier with electrostatic headphones: owners’ review

Tantal, the Demograf Audio amplifier on 3C24 triodes with tantalum anodes, drives electrostatic, planar and dynamic headphones from one chassis, as well as sensitive loudspeakers. Between 2015 and 2023 forum listeners heard it in several owners’ systems: a headphone system with a Demograf Audio CS4397 DAC, other headphone chains, and a loudspeaker system with Demograf Audio loudspeakers. They brought the Sennheiser HE 90 Orpheus, STAX SR-009, SR-Omega and SR-007, handmade electrostatic headphones, and planar and dynamic models from AKG, HiFiMAN, Fostex, Beyerdynamic and Abyss. This article collects what they heard.

These impressions are summarised and translated from owners’ posts on an audiophile forum. They are the subjective views of their authors, not measurements or claims of Demograf Audio. The amplifiers described are earlier builds of Tantal; the current model is Tantal, and the CS4397 DAC is offered today as Hyperion.

The systems

A system for the Sennheiser HE 90 Orpheus

One owner, Pol542, built his chain around Demograf Audio electronics: a CS4397 DAC, a Krell KPS 20 transport modified for an external clock, the clock and the Tantal amplifier, with Audio Note loudspeakers. The amplifier was made mainly for his Orpheus. His brief was a sound that would play the rock of the 1960s and 1970s, would not be bright, and would keep the airiness on jazz that is typical of the Orpheus. Another visitor described this amplifier as a balanced design for electrostatic headphones with outputs for STAX and Orpheus, plus a 6.3 mm jack and two balanced sockets for other headphones.

A loudspeaker system

Another owner, Farkhat, ran a Tantal with large floor-standing loudspeakers from Demograf Audio’s early years, which are not a current model, and with a STAX SR-007 for headphone listening. Several forum members visited between 2015 and 2017.

How does Tantal sound with electrostatic headphones?

Sennheiser HE 90 Orpheus

• A collector, borlebsin, heard the Orpheus become even richer and more detailed while keeping its clarity, transparency and comfort. On a pipe organ the lowest notes grew richer as the volume rose, without losing transparency.
• Through a Woo Audio WES the Orpheus sounded very good to him, but part of the transparency and depth of presentation was gone.
• The owner described the electrostatic presentation as warm, not bright and dynamic, with smoother treble air than the WES and no loss of detail, a large and deep stage, precise imaging and a coherent, singing sound.

STAX SR-009 and SR-Omega

• borlebsin found the SR-009 neutral, balanced and harmonious through Tantal, good enough to mix recordings on; through a Woo Audio amplifier they sounded simpler to him. With the AL4 amplifier Demograf Audio had built for another collector he missed bass in the SR-009, while with Tantal he had enough.
• The owner heard plenty of bass, from which the Orpheus and the Omega only gained.

STAX SR-007

• With the SR-007 the owner of the HE 90 system found the bass too much, and he considered asking for a tighter low end.
• borlebsin heard the host’s SR-007, fitted with extended pads, as much more balanced, with cohesive sound and natural timbres, though less detailed in the top octave than the SR-009. Another visitor found the two similar, the SR-007 with a little more bass.
• In 2021 a listener had his strongest emotional response of the evening with a Tantal and an SR-007A, on Saint-Saëns’s Second Piano Concerto.

Handmade electrostatic headphones

In 2017 two visitors compared three pairs of handmade electrostatic headphones on the Tantal in the loudspeaker system: their own pair, a friend’s, and Dmitriy’s own pair with an open membrane.

• One of them heard precise placement of instruments in a large, layered space, with no loss of technicality, and liked Dmitriy’s pair best for its even, accurate and detailed sound.
• borlebsin was first won over by the open-membrane pair: more air, a livelier treble, a rich orchestra, and about two volume steps more sensitivity. Then he played opera and changed his mind. On his own pair, voices had fuller chest harmonics and a wider range, and an organ’s deepest notes came in waves, as in a church. He concludes that the open membrane is not a universal answer and may suit a darker system better.
• He also noticed that as the volume rose, Tantal’s sound grew richer and more detailed and stayed clean, while a STAX SRM-007t II at a similar level turned muddy.

Dynamic and planar headphones

• AKG K812: borlebsin heard a good centre, a much richer spectrum of harmonics in the lower range and, compared with his DAC alone, a darker but cleaner and freer sound, with little rise in distortion as the volume went up. He found an unexpected synergy, which surprised Dmitriy too: deep organ bass, and an overall balance on voices closer to the Orpheus than any other headphone that day. At high volume, though, the K812 itself began to overload. A friend, sankutzo, liked its balance, speed and sharp bass on Tantal and also notes that AKG headphones do not take high levels well.
• HiFiMAN HE-6: driven with ease, at about 12 o’clock on the volume control. sankutzo thought them suited to rock played loud.
• Beyerdynamic T1: listener kleymor.metal heard them play with a freedom he had never heard from them: better bass, a much larger stage and dynamics close to what he hears when he plays music himself. He puts it down to the amplifier’s current and voltage headroom.
• Abyss AB-1266 Phi TC: a listener who had not liked these headphones on rock through a neutral chain heard them come alive through Tantal, with dense, punchy, rhythm-led bass. He calls the pair excellent for rock and metal.
• HiFiMAN Susvara: detailed across the range, with a refined midrange and deep, textured bass.
• Fostex TH900: too much bass pressure for borlebsin at normal levels.
• Older STAX Lambda: sharp treble and no bass. borlebsin concludes that Tantal is not for them.

Compared with other amplifiers

vs Woo Audio WES

sankutzo switched from Tantal to the WES and wanted to go back within seconds; for him the difference was large, not subtle.

vs other electrostatic amplifiers

kleymor.metal placed Tantal above the electrostatic amplifiers he had heard before, among them the Woo Audio WES Maxxed, a Flux Lab KGBH SE, an ES Static and STAX’s own units: in stage, dynamics, control, resolution and timbre, with the least obvious tube colour. He felt that with electrostatic headphones it was voiced more restrained than with the T1.

vs Demograf Audio’s AL4 push-pull amplifier

borlebsin also knew an earlier Demograf Audio push-pull electrostatic amplifier on AL4 tubes, built for another collector. He found it no worse than Tantal, only different: Tantal more even and, at its owner’s request, slightly dark; the AL4 amplifier lighter and very refined, with colourful vocals on the Orpheus. Ideally he would keep both. A dedicated AL4 push-pull electrostatic amplifier of this kind, Rubedo, is documented in our archive.

vs Feliks Audio Envy with the Abyss AB-1266

The 2023 listener had found an Aqua Formula DAC with a Feliks Audio Envy neutral and midrange-focused: excellent with the HiFiMAN Susvara, less so with the Abyss. Tantal, with more density, punch and slightly coloured timbres, suited the Abyss better for him.

Tantal with loudspeakers

Visitors to the loudspeaker system describe a sound built for live acoustic music. Bahobaho heard opera, symphony orchestra, choirs and folk music with full immersion, a large three-dimensional stage and a natural, harmonious sound. Listeners used to multi-way loudspeakers and solid-state amplifiers, he warns, may find it plain at first, without emphasised bass or treble. Rock sounded tasty, though not for headbanging.

Denry could not point to the loudspeakers with his eyes closed: the stage was much wider than the distance between them. Another visitor heard no instant wow, then a gradual immersion, a seamless flow without digital edge that reminded him of vinyl. He calls the Tantal the heart of that system.

Reported limits

• Bass can be too much with the STAX SR-007 and the Fostex TH900.
• Older STAX Lambda models did not suit it.
• One collector expected a dark amplifier and found it, in that system, slightly light and a touch bright instead.
• Its loudspeaker presentation is calm and natural rather than spectacular, which some listeners need time to adjust to.

Summary

Owners describe Tantal as a universal amplifier: rich and dynamic with the Orpheus and the SR-009, free and controlled with demanding dynamic headphones, and immersive with loudspeakers. Its bass is generous, which helps the Orpheus and the Omega but can overwhelm the SR-007, and owners stress that the best results come from matching it with headphones that leave room for that weight.

Which Demograf Audio piece fits

• One amplifier for electrostatic, planar and dynamic headphones and sensitive loudspeakers: Tantal, two 3C24 tantalum-anode triodes in Class A, 3 W per channel, with a STAX-type output built in.
• More power for loudspeakers: Tantal Senior on 4E27 tantalum-anode pentodes, 30 W per channel, with a STAX electrostatic output as an option.
• The source: Hyperion, the CS4397 DAC, with a solid-state or tube output stage. Owners’ reviews of the DAC on its own are collected in Hyperion CS4397 tube DAC: owners’ reviews.

Our guide to amplifiers for headphones and loudspeakers explains what an electrostatic output needs. Every amplifier is made by Dmitriy Gubchenko. Each is made to order with a one-year warranty (extra warranty available: +1 or +2 years), so tell us which headphones you use before the build starts.