EternalArts HLP – combined Headphone Amplifier and Line Level Preamp


After the highly acclaimed Futterman OTL Mk II, which made its debut at the High End 2008, other tube-based components gradually followed - powerful OTL monoblocks, an extraordinary preamplifier for vinyl enthusiasts, a CD player with a tube output stage and probably the only radio receiver in the world based on the DVB-S standard and with a tube output stage.

This was followed by an extraordinary dipole loudspeaker at High End 2010, which immediately moved into the absolute top of the range on the world market.

The following year, the trend towards “personal audio” at EternalArts led to three high-end headphone amplifier models in OTL technology, designed for top-quality headphones. All models were also unanimously classified by the trade press in the absolute top class of the range.

In order to fulfill the obvious wish to have a high-quality audiophile pre-stage available at the same time as a headphone amplifier, a new product was developed: the EternalArts HLP. The compact component is a high level preamplifier with three inputs, which was created on the basis of the circuitry of the headphone amplifier. Thus it benefits from the ingenious basic concept of voltage stabilization, which was introduced by Neumann in the 1940s for feeding condenser microphones.

The special development effort for this puristic high-level preamplifier was due to the fact that both modes of operation – headphone amplification and signal pre-amplification for an output stage – have different requirements. In one case it is a power supplier to drive converter systems, in the other to supply voltage to control output stages.

Thanks to an ingenious switchover, the new EternalArts HLP does justice to both tasks and creates a sound image of outstanding calmness, splendor of color and attention to detail in both.

The EternalArts combination of a high-end preamplifier with headphone amplifier transfers the ingenious Futterman idea of ​​a transformerless tube amplifier to a compact, puristic high-end switching center for all types of power amplifiers and active monitors.

  • Compact preamplifier module for the connection of three high-level sources and a hi-fi headphone implemented in a two-part powder-coated sheet steel housing with a high-gloss black acrylic front, solid nickel-plated feet made of solid metal and a volume knob

  • Headphone section optimized for high-impedance high-end headphones such as the HD800 from SENNHEISER

  • Can be switched to operation with low-impedance headphones > 20 ohms

  • Circuit design with a total of 4 tubes: 2 triode pentodes, 2 stabilizer tubes for gain-independent stable anode voltages of the amplifier tubes

  • Board-supported structure with gold-plated, 70µ double-sided laminated conductors

  • Cast multi-voltage transformer in toroidal core technology with protective winding between the primary and secondary winding package, Mu-metal (permalloy) shielding between the board and the transformer

  • High quality selected components, classic ALPS potentiometer, gold-plated headphone socket, gold-plated Neutrik cinch sockets, relay-controlled switching of the sources

  • Multiple secured, absolutely stable circuit for maximum safety and a very long tube service life

  • Phenomenal transmission bandwidth and pulse train

  • Made in Germany

Circuit description

Technical data


Construction material

Black hight-gloss powder-coated steel casing and hood. High-gloss black acrylic front plate, nickel-plated knobs and feet

Amplifier tubes


Power supply

2 x 14GW8 / PCL86 each channel

STV 108/30 / 6074 each channel

Input impedance

> 20 k Ohms

Output impedance

preamp: approx. 300 ohms

Headphone: 300 ohms / > 20 ohms

Frequency response

6 to 40.000 Hz +/- 0,5 dB

THD (1KHz, 400 mVs, 300 ohms)

≤ 0,4%

Signal-to-noise (related to 1V)

> 80 dB

Subject to change without notice

The signal is transferred to the screen of the triode via a potentiometer. At its cathode there is an RC element with adjustable R in order to be able to regulate the amplification of the triode. The anode then controls the control screen of the pentode via an RC element. A low inner resistance is reached as a result of the cathode follower.The signal is decoupled at the cathode and the direct current elements are eliminated using a capacitor. The signal then reaches the output via a fuse and two Z-diodes as overvoltage protection.

As a special feature, there is a stabilizer tube in the circuit that keeps the anode voltages of the triode pentode constant regardless of their level. The latter is direct current heated via an RC element and double buffering. In addition, the shield is supplied by a RC-filter. The aim was to ensure that the preamplifier was free of interference voltages. For the assembly, new tubes from old stock were used, which are still available. To identify the tubes selected by EternalArts, they have the golden EternalArts tube imprint.

Classical High End