CS4397 tube DAC and Tantal: one owner’s long-term review

Over 2023 one owner built a headphone system around Demograf Audio electronics and wrote about it at length: a CS4397 DAC made to his order with interchangeable output tubes, a Tantal amplifier on 3C24 triodes, and a new amplifier on 811-type triodes. He set them against a Rockna Wavedream Signature DAC, a Krell Reference 64 and a Feliks Audio Envy amplifier, mostly on heavy metal, folk and vocal music. His thread also covers much other equipment; below we summarise only what concerns the Demograf Audio units, including the comparisons he lost.

These impressions are summarised and translated from an owner’s posts on an audiophile forum. They are the subjective views of their author, not measurements or claims of Demograf Audio. The units are earlier builds: the CS4397 DAC is offered today as Hyperion, the 3C24 amplifier as Tantal, and the 811 amplifier as Helios MkII.

The DAC: one CS4397 converter, four output stages

Earlier Demograf Audio CS4397 DACs each had one type of output tube: AL4, EL8 or EF14. His unit takes any of the three, or runs with a solid-state output and no tubes.

How the output tubes compare

• EF14: the most detailed of the four, even more than the solid-state output. He calls it the airiest, most musical and most delicate option, and it stays in his DAC most of the time.
• Solid-state: a less musical, more distant midrange, so he likes it less. One of his guests preferred it.
• EL8: about as detailed as the AL4, but brings the midrange forward and makes it denser, more melodic and richer on vocals. Another guest liked it best.
• AL4: a fuller, punchier, slightly V-shaped sound. He tried four different AL4 tubes and kept the fullest-sounding one as his second favourite.

A treble control he now uses with every headphone

Dmitriy also fitted a treble control with five positions, which the owner had not asked for and now calls the feature he values most. He sets it for each pair of headphones. At the brightest position the Audeze LCD-4z suddenly sounded airy to him, helped by other changes in his chain; with the LCD-5 he needed one step beyond the middle to stop sibilants cutting; even his Kennerton headphones, which tend to harshness, became comfortable. Higher settings never made the sound muddy. Today’s Hyperion offers a tone control / filter module among its options.

Dynamics and air

He calls the dynamics the best he has heard from a DAC: light, weightless, breathing. Because it breathes so freely he first thought it bright, but next to a friend’s Krell Studio it was not brighter at all, with only slightly less bass.

Compared with other DACs

vs Rockna Wavedream Signature

He brought a Rockna Wavedream Signature, with a Wavedream NET endpoint, specifically to compare it with Demograf Audio DACs over I2S. He agrees that the Rockna sounds better over I2S than over other inputs, but the differences stayed where they were. Early on, with the Rockna not yet run in, he heard the Demograf Audio EF14 DAC as fuller and richer in timbre and clearly ahead in dynamics, transparency, resolution and separation.

Later, in one chain he valued highly, a Feliks Audio Envy with Heddphone One headphones, the picture was different. Replacing the Rockna with the Demograf Audio EF14 DAC made the sound warmer in the midrange, with more decay, richer timbres and punchier, better bass. But microdynamics and imaging in the midrange became slightly worse, and the synergy of that particular chain weakened. He took it as a lesson that devices should be judged in the systems that suit them.

vs earlier Demograf Audio CS4397 DACs

Compared on the same output tube, the older EF14 and EL8 DACs sounded fuller and denser, but much less airy and large-scaled, simpler in the top-octave resolution, less dynamic and softer in the bass. The older EL8 unit was slightly ahead of his in midrange resolution; with EF14 tubes his own DAC overtook it.

vs Krell Reference 64

At a large meeting in late August he compared Demograf Audio CS4397 DACs with a Krell Reference 64. He describes three versions:

• AL4 output, the simplest build: midrange and treble close to the Krell’s level and with the same resolution, but different in character. The Krell was colder, punchier, more precise and more distant; the Demograf Audio DAC denser, warmer, more saturated and more cohesive, with an audibly larger stage. The midrange was more pleasant on the Demograf Audio side.
• EL8 output: clearly ahead of the Krell in midrange richness, resolution, imaging of instruments and timbre, though less punchy than the AL4 version.
• EF14 output: calmer and more musical still. In two separate comparisons he heard it ahead of the Rockna Wavedream Signature on the energy of drums.

Where the Krell clearly won was bass: lower, firmer, more sculpted and more dynamic than any of the three. He calls it the best bass he has heard, and sees the old dilemma: delta-sigma converters rarely have the bass he wants, multibit ones the treble. By delta-sigma standards he rates the Demograf Audio bass among the best he knows, and he is keeping his DAC.

Amplifiers: Tantal, the 811 amplifier and the Feliks Audio Envy

Tantal vs Feliks Audio Envy on planar headphones

The owner has a Tantal of his own and compared another owner’s Tantal in its top configuration, which he describes as almost the same as his, with a Feliks Audio Envy, using Snorry Trion MK2 planar headphones and a Demograf Audio CS4397 AL4 DAC. He sums up Tantal as full, dense, dark and musical, and the Envy as even, fast and transparent. On planars he heard the Envy as a class above: more detailed and dynamic, with firmer and faster bass and clearer blast beats. Tantal had more body and better decays, and the stage was almost equal, Tantal slightly deeper and more intimate.

He also tried DCA Voce electrostatic headphones on Tantal against the Trion on the Envy, and the Envy chain won again. Yet away from direct comparison, it is Tantal with the Trion that he wants to listen to on metal; with the Envy he never had that feeling. With his handmade electrostatic headphones he has no doubts: in his view they give far more than any planar, and the Envy has no electrostatic output.

An amplifier on G-811 triodes

For his second amplifier he gave Dmitriy a brief for hard-hitting, massive bass, wild dynamics, high resolution, scale and a light warmth in the midrange, and writes that it hit every point. Against his Tantal it is noticeably more detailed and dynamic, while Tantal is more midrange-centred, saturated and dark. His plan is Tantal for folk and vocal music and the 811 amplifier for everything else. How it compares with the Feliks Audio Envy, and how it sounded with the Sennheiser HE 90 at a later session, is told in Sennheiser HE 90 on an 811 tube amplifier.

Headphone pairings that stayed with him

• Tantal with handmade electrostatic headphones, at low volume, on folk: he describes complete immersion, a warm, singing voice that seemed to come from nowhere and everywhere, and headphones so light he forgot he was wearing them.
• Tantal with the Sennheiser HE 90 Orpheus: on folk, vocal and choral music, no trace of the speed problems friends had described with the Orpheus’s original amplifier. He heard the richest midrange of his experience, helped by a slight lift in the upper midrange and lower treble, with excellent treble, dynamics and stage. The bass was fast and lean, not deep or massive, so he would not call the pairing universal.
• Tantal with the Snorry Trion MK2: on heavy metal at high volume, the most full-bodied metal he has heard, with an impressive technical level.

His Tantal and a Tantal in its top configuration

On one visit Dmitriy compared the owner’s Tantal with another owner’s Tantal in its top configuration, refined it on the spot and took it back for further work: better output transformers, a regulator and new inter-stage capacitors, leaving the other unit ahead only in its larger Duelund capacitor banks.

In August 2023 he went to a friend’s session to find out whether the magic of his own Tantal would survive on a Tantal in its top configuration, which he describes as less warm and less saturated but more detailed, transparent and dynamic.

• With his older handmade electrostatic pair, at low volume, on folk: the singing quality he hears at home was not quite there, and the sound was less warm. Yet he also heard what he called the best sound of his life: micro-contrast and instrumental timbre fine enough to tell where a guitarist used a pick and where he plucked with his fingers, and tube decays that shimmered.
• With a top-configuration Demograf Audio CS4397 DAC, its filters switched off, and the Snorry Trion MK2 on heavy metal: massive, juicy, full-bodied bass, hard and fast sub-bass reaching to the bottom, excellent separation and resolution, and an obviously tube-like texture with rich decays. He called it exactly the presentation he wants for heavy metal.

Where it did not work

• On Tantal, the Heddphone One showed an unnatural peak in the treble.
• In one session his handmade electrostatic headphones sounded soft and not right to him from Tantal, so he used a portable amplifier for them that day; he could not explain it.
• Against the Feliks Audio Envy, Tantal lost on technicality with planar headphones.
• No Demograf Audio CS4397 DAC matched the bass of the Krell Reference 64.

Summary

For this owner the CS4397 DAC is the fixed point of his system: dynamic, airy and adjustable to each headphone, with bass he rates highly for a delta-sigma design but below the Krell Reference 64. Tantal is the amplifier he keeps for emotion, folk and electrostatic headphones, though he heard the Feliks Audio Envy as more technical on planars.

Which Demograf Audio piece fits

• The CS4397 DAC: Hyperion, with a solid-state output or a tube output stage on EF14, EL8, AL4 or ML6, a tone control / filter module and an I2S (HDMI) input among the options. Owners’ reviews of the DAC on its own are collected in Hyperion CS4397 tube DAC: owners’ reviews.
• Electrostatic headphones and vocal music: Tantal, with a STAX-type output built in.
• Power-hungry planars and loudspeakers: Helios MkII on G-811 triodes, 15 W per channel, with an electrostatic output as an option.

The trade-offs between chip types are explained in our guide to NOS and multibit DAC chips. Every unit is made by Dmitriy Gubchenko. Each is made to order with a one-year warranty (extra warranty available: +1 or +2 years), and the output tubes and options are agreed before the build starts.