Note: These are a pre-sale estimated to ship late November. Transit will take about 2 weeks after.

Engineered for Safe, Transparent Electrostatic Playback

The EHT-7 unleashes the full potential of your electrostatic headphones while integrating with your existing speaker amplifier or headphone amplifier. Its exceptional driving capabilities deliver a natural and realistic soundstage, and preserve the ultimate transparency and detail retrieval that electrostatic headphones are famed for.

Innovative transformer-based energizer design

Unlike conventional transformer setups, the EHT-7 incorporates innovative design considerations and technologies, which ensures a reliable and safe handling of the high voltage needed to power electrostatic headphones. This amplifier is crafted for music enthusiasts seeking the ultimate performance from electrostatic headphones.

Japanese-crafted transformers with exceptional high-frequency response

The step-up transformers have a fundamental role in shaping the sound of the EHT-7. The audio-grade transformers used in the EHT-7 are crafted in Japan, with each piece assembled by technicians to ensure the highest quality. The cores are made from grain-oriented silicon-iron steel from Nippon Steel Corporation. The effort put into the manufacturing process resulted in the excellent sonic performance of the transformers,
with an exceptional high-frequency response.

Optional Lundahl LL1630 transformer upgrade

The EHT-7 also offers the option of using Lundahl LL1630 transformers from Sweden, famed for their superior sound quality and measurement results by the community. It features a special audio C-core of Lundahl's production. Furthermore, the transformer is highly sectioned, and wound with a special low capacitance winding technique, resulting in an excellent high-frequency performance.

Multi-stage clean bias power architecture

The EHT-7 utilizes multiple stages of power processing to deliver a clean bias supply for the electrostatic headphone for optimal performance. This approach stands in contrast to the outdated voltage multiplier design, which is known for its noise generation but commonly used in conventional electrostatic energizers.

Low-noise regulation and high-voltage conversion

The EHT-7 draws power from an external switching power supply, feeding it into an ultra-low-noise LT3045 regulator circuit. The regulated voltage is then sent to a low-ripple, high-voltage DC-DC converter module, which generates the 580V bias required for the Pro Bias electrostatic headphone.

Impedance options and dual input connectivity

The EHT-7 offers adjustable impedance (8 Q or 16 0) for the primary windings of the transformers, ensuring optimal compatibility with your source amplifier. It also features two input options: speaker termination for connection to your speaker amplifier and XLR balanced input for connection to your headphone amplifier.

Relay-based signal switching

The signal switching in the input section is controlled by a set of 5 sealed silver-alloy contact relays, designed for a long lifespan and high current capacity.

Comprehensive protection and safety systems

Safety is never compromised in our products, and the EHT-7 is no exception. Multiple measures are in place to protect the headphone, source amplifier, and the EHT-7 itself.

• A clipping circuit formed by a network of zener diodes prevents signals exceeding 1150V peak (stator-to-stator) from reaching the headphone.

• A pair of matched load resistors from Jantzen Audio are serially connected to the transformers, safeguarding against excessive DC current or impedance fluctuations that could damage the transformers.

• A Vishay 4.7M high-voltage ballast resistor limits current before the bias reaches the headphone.

• Built-in short-circuit protection is integrated into both the low-voltage regulator and the high-voltage DC-DC converter.

• The input circuitry is disabled when the EHT-7 is powered off

Product highlights

• Interfaces with existing speaker or headphone amplifiers

• Natural, transparent soundstage with exceptional detail retrieval

• Japanese-crafted audio-grade transformers with silicon-iron steel cores

• Optional Lundahl LL1630 C-core transformers from Sweden

• Multi-stage power conditioning for clean, low-noise 580V bias

• LT3045 ultra-low-noise regulation + high-voltage DC-DC conversion

• Adjustable input impedance (8Ω / 16Ω) for optimal amplifier matching

• Speaker-level and XLR balanced inputs

• Sealed silver-alloy contact relays for high-integrity signal switching

• Extensive protection: clipping control, load resistors, ballast resistor, short-circuit protection, bias safeguards

• 2-year warranty

Specs

• Output Connection Type: Stax 5-pin Pro Bias

• Output Voltage Protection Threshold: 1150V peak (stator-to-stator)

• Power Input: 15VDC / 0.2A

• Power Constion:

• Dimensions: 215mm (Length) X 235mm (Width) X 80 (Height)

• Weight: 3.1 KG

• Warranty period: 2 years

• JP Transformer

  • Gain (8 Q): 31.1 dB

  • Gain (16 Q): 27.8 dB Frequency Response: 10 Hz - 55 kHz

  • (80/-3dB, 50V rms,120pf load, Source: Topping LA90D)

  • Recommended Input Power Requirements:

    • Speaker Amplifier: 5W - 100W/80

    • Headphone Amplifier: 10V/160 or more

• Lundahl LL1630

  • Gain: 23.0 dB

  • Frequency Response: 10 Hz - 65 kHz

  • (-3dB, 50V rms, 120pf load, Source: Topping LA9OD)

  • Recommended Input Power Requirements:

    • Speaker Amplifier: 10W - 100W/80