Feliks Audio Envy

Single-ended Class-A 300B tube headphone amplifier with transformer-coupled output

Envy is a single-ended Class-A tube headphone amplifier with a transformer-coupled output, designed for planar-magnetic and dynamic headphones with an impedance range of 16 to 600 ohms.

Feliks Audio Envy features a 3-range impedance selector (for guidance):

• Low – recommended for headphones 16–60 Ω
• Mid – recommended for headphones 60–300 Ω
• Hi – recommended for headphones 300–600 Ω (and for some planars)

For planar-magnetic headphones, we recommend choosing the best possible setting starting from “Low”. Most planar headphones have low impedance but require more current to be driven properly.

If you set the impedance range to “Mid”, you can also use the headphone output (the 6.3 mm output) to connect 16-ohm stereo speakers, which the amplifier will drive at around 5 watts. Naturally, relatively high sensitivity is recommended (e.g. >94 dB), but this function demonstrates the Envy’s flexibility and power capability.

Standard Edition includes:

• Electro Harmonix Gold 300B power tubes
• High-quality copper signal wiring

Performance Edition includes:

• Full Music 300B power tubes
• UPOCC (single-crystal copper) signal wiring

Mechanical design

Feliks Audio Envy is built on a solid metal chassis and finished with natural, premium oiled wood. The front panel offers two headphone outputs: balanced 4-pin XLR and single-ended 1/4" (6.35 mm). Additional front-panel controls include the touch-sensitive standby button, the volume knob, the impedance selector, and the input selector.

The input selector lets you choose one of three options: unbalanced RCA source (IN1 or IN2) and balanced XLR source (IN3, left and right channel).

The touch-sensitive standby button includes an LED indicator. To fully power off the amplifier, use the physical switch on the rear panel near the AC inlet.

Envy can operate as a preamplifier with a high maximum output level (up to 10 V RMS). On the rear panel you’ll find a pair of RCA preamp outputs as well as two XLR connectors for a balanced preamp output. Output level is controlled by the volume knob.

Electrical design

At the input there is an Alps RK27 potentiometer, followed by a two-stage preamplifier using CV-181 tubes and Jantzen Superior Z-cap coupling capacitors. The output tubes are directly heated 300B tubes. Output transformers are custom high-end audio units.

Feliks Audio Envy features fully automatic bias and a feedback-free circuit design. The power tubes are DC-heated, with a dedicated circuit separating tube heating from the audio-path power supply. The anode voltage supply is solid-state, based on MOSFET transistors and low-noise current sources.

For the balanced XLR input, top-tier balanced Lundahl transformers are used. Input selection is handled via high-end low-signal relays placed directly behind the input connectors to limit interference and noise.

The amplifier is built using point-to-point technology. All wired connections are made from single-crystal copper (UPOCC) with Teflon insulation.

Box content

• Matched pair of driver tubes CV-181 (6SN7)
• Matched pair of power tubes 300B
• AC cord
• User manual
• Warranty card

Technical specifications