Demograf Audio 300B amplifier and CS4397 DAC: a headphone system reviewed by listeners

Between 2018 and 2022 one headphone system, built around a Demograf Audio DAC on the Cirrus Logic CS4397 and a Demograf Audio amplifier on 300B triodes, hosted several meetings of forum listeners. Its owner, known on the forum as Sergst, voiced the system for jazz and light music, but his guests also played rock and metal and brought their own DACs and amplifiers to compare. Below we summarise what three of them 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. Both units are earlier builds, not current catalogue models: today the CS4397 converter is offered as Hyperion and the 300B amplifier as Atlas.

The system

The DAC is a delta-sigma converter on the CS4397 chip with a tube output stage. The amplifier uses 300B triodes and drives headphones. The owner’s main headphones were a pair of TDS-7 isodynamic (planar) headphones rebuilt by the maker Snorry in Audeze LCD-3 housings, alongside a Beyerdynamic T1. Guests also brought a Krell Studio DAC, an Audio Note P2SE amplifier, a solid-state Beta22 and a high-end solid-state headphone amplifier.

Sound of the DAC and the 300B amplifier together

A visitor in 2022 called it a rare tube system that does not sound lifeless or slow. Many tube amplifiers, in his experience, play without punch or dynamics; this one had fast attacks, dynamics and punch, a warm midrange, and could still play hard death metal. He heard the two units working in good synergy:

• The DAC: a stage with real depth, good resolution in the treble, fast attacks, dynamics and a general sense of punch.
• The amplifier: it keeps all of that intact, which is why it can be heard at all, and adds a pleasant tube warmth in the midrange.

Compared with other DACs and amplifiers

DAC vs Krell Studio

A guest in 2019 compared a Krell Studio DAC with the Demograf Audio DAC, each driving an Audio Note P2SE amplifier and the TDS-7 headphones. He preferred the Demograf Audio pair: to him it drew more information from the music and sounded more melodic, closer to the sound he likes. He also noted that during the evening the Krell had the strongest bass and punch of all the DACs, except the Demograf Audio one.

300B amplifier vs a high-end solid-state amplifier

The same guest then compared the 300B amplifier with a high-end solid-state headphone amplifier, both fed by the Demograf Audio DAC. With the Audio Note P2SE he had found the solid-state amplifier and the P2SE roughly level, separated by small nuances. Against the 300B, the solid-state amplifier was slightly more transparent and had slightly heavier bass, but did not give the energy of the 300B. He found the two very close, which surprised him for a tube against a transistor amplifier. What surprised him most was the 300B amplifier’s speed and bass, no worse than the solid-state design, with no large difference in air or stage.

Tube amplifier vs Beta22

At a 2018 meeting a listener heard the Demograf Audio DAC with a solid-state Beta22 and with the tube amplifier, on music such as Disturbed and Dimmu Borgir chosen to test speed and technique. The planar headphones opened up best with the Demograf Audio DAC and the Beta22: through the tube amplifier he found their presentation too dense and too close, while the Beta22 added space, speed and control and kept their weighty bass. The Beyerdynamic T1 worked well with both amplifiers:

• With the Beta22: speed, technique, a wide stage, a fresh and transparent sound and very high detail.
• With the tube amplifier: more tangible bass and a fuller, more flavourful sound.

He suspected that an earlier disappointment with the Sennheiser HD 800 had been caused by a CD drive rather than by the tube amplifier: played from a file source through the Demograf Audio DAC, the HD 800 sounded as it should, wide and large-scaled, with extra transparency and clarity. He was of two minds about the custom-built amplifier and headphones he heard that evening. On one hand he noted a high level of sound, extra transparency, detail and technique that he could not fault. On the other, the sound lacked pedigree, completeness and coherence for him; it seemed a little raw, like an oil painting with masterfully drawn details but a broken overall composition. He stressed that this was only his personal opinion.

A dissenting view

Writing again in February 2019, the same listener was clearer. He found the Demograf Audio tube amplifier too soft and not dynamic enough for him, since he loves heavy music, and even on classical music he wanted more expressiveness. He pointed out that the system’s owner had tuned it for jazz and for his own preferences, which hardly match his. In his words, the amplifier is without doubt powerful and interesting, but not his kind of sound. He also noted that the evening had been hurried, with many guests passing headphones around and digital replay set up mainly for CD, so he wrote no full review at the time.

Summary

Guests agree on the DAC’s deep stage, treble resolution and punch, and on an amplifier that keeps that speed while adding warmth in the midrange. One listener preferred the Demograf Audio DAC to a Krell Studio for information and melody; another found the 300B amplifier close to a high-end solid-state design, with more energy and only slightly less transparency. A third heard a solid-state Beta22 as faster and wider, and the tube amplifier as fuller and more flavourful, but for heavy music he found it too soft and not dynamic enough. The system was voiced for jazz, and listeners who want maximum attack and expressiveness should audition it with their own music.

Which Demograf Audio piece fits

• A 300B amplifier for headphones and sensitive loudspeakers: Atlas, a single-ended Class A integrated on 300B triodes, 5 W per channel, with 6.3 mm and 4-pin XLR headphone outputs.
• The CS4397 DAC: Hyperion, with a solid-state output as standard or a tube output stage on EF14, EL8, AL4 or ML6 tubes. Owners’ reviews of the DAC on its own are collected in Hyperion CS4397 tube DAC: owners’ reviews.
• Faster bass for rock and metal: Solaria on 45 triodes. For more on how the output tube shapes the sound, read our guide to power triodes in single-ended amplifiers.

Every unit 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 and music you use before the build starts.