Two early Demograf Audio headphone amplifiers: a 6B4G and a transmitting triode

Before the current catalogue, Demograf Audio built headphone amplifiers to order around whatever tube suited the owner. Two owners wrote about theirs in detail: a 6B4G amplifier bought in 2014 for a Sennheiser HD 800, and an amplifier on large transmitting triodes that was already about ten years old in 2011. Neither is a current model, but both show the sound Dmitriy Gubchenko was after. We summarise what the owners heard.

These impressions are summarised and translated from owners’ posts on an audiophile forum written in 2011 and 2014. They are the subjective views of their authors, not measurements or claims of Demograf Audio. Neither amplifier is a current catalogue model.

A 6B4G amplifier for the Sennheiser HD 800

The 6B4G is a directly heated triode of the 2A3 family with a 6.3 V filament. An owner known on the forum as mebius spent a long time choosing an amplifier for his HD 800, a headphone known to be demanding of amplification. He auditioned a great many, visited other owners’ systems, and decided after visiting Dmitriy and hearing his amplifier. It replaced a Burson HA-160, which he still rated as a good amplifier for its price.

Sound

• The HD 800 sounded very detailed, yet whole, without breaking into separate sounds.
• The sound was darker and more full-bodied than with the Burson; Cecilia Bartoli began to sing with a fuller chest voice.
• In his words, music was no longer reproduced but played. Grieg’s music for string orchestra swept him away, and Chopin’s nocturnes moved him with their refinement.

Metal on the HD 800

The surprise came when he put on Death out of curiosity. The HD 800 is widely said not to play metal, yet he listened to Spirit Crusher in one breath, then to more Death and Obituary, then to doom, which he had already enjoyed on the Burson and found even better now. The HD 800 became, for him, a headphone for every genre.

Audio-Technica ATH-W1000X

He was at least as surprised by his Audio-Technica ATH-W1000X. They were transformed: he felt the music physically, filling everything and sweeping other thoughts away, so that it could no longer serve as background. He had always liked them; now, he wrote, he loved them.

A transmitting-triode amplifier with the HiFiMan HE-6

In 2011 an owner known as Khronos wrote about a Demograf Audio amplifier on GM-70 transmitting triodes, nicknamed the “household stove”, which by then was about ten years old. He compared it with a Flux solid-state headphone amplifier that he otherwise rated very highly.

• The two sounded fundamentally different, and the Flux did not put him off at all: it was softer and more measured, but less emotional, even a little dull.
• The Flux built a flatter, wider stage; the triode amplifier a narrower but deeper one.
• Bass quantity was the same, but the triode amplifier’s bass was tighter: a bass hit felt like a small earthquake rather than just a hit.
• Vocals clearly favoured the triode amplifier, with more emotion and expression. With it, he wrote, music was simply music.
• It calmed sibilance and the treble in general, which gave good synergy with his HiFiMan HE-6 and its silver cable.

He was interested in the amplifier less as a model of detail and transparency than for its power and drive, and noted that its parts and input tubes were modest. Different transmitting triodes also changed its sound: the less prized ones he heard one evening suited him better, combining strengths of both amplifiers. Of all the tube amplifiers he had heard, he wrote, only Dmitriy’s made him fall for this kind of sound.

Reported limits

• Through the 6B4G amplifier the HD 800 sounded darker than through the Burson, which suited mebius but changes the HD 800’s usual balance.
• The transmitting-triode amplifier built a narrower stage than the Flux, and its parts and input tubes were modest.

Summary

Both owners describe an amplifier that put music and emotion ahead of analysis. The 6B4G made the HD 800 fuller and darker and let it play death metal; the transmitting-triode amplifier gave the HE-6 a deeper stage, tighter bass and calmer treble than a well-regarded solid-state amplifier.

Which Demograf Audio piece fits

• Eurybia uses the 2A3, the tube family of the 6B4G: single-ended Class A, 2 W per channel, with a dense, full-bodied sound and a slightly darkened picture.
• Solaria, on 45 triodes, has a faster, harder-hitting bass for rock and metal on high-sensitivity loudspeakers and headphones.
• For hard-to-drive headphones such as the HiFiMan HE-6, Helios MkII runs G-811 triodes at 15 W per channel.
• For large transmitting tubes today, see Ether, 25 W per channel in single-ended Class A.

Every amplifier is made to order by Dmitriy Gubchenko, with a one-year warranty (extra warranty available: +1 or +2 years). Our guide to power triodes for single-ended amplifiers compares the 2A3, 45, 300B and larger tubes.