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 from 16 to 600 Ω.

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 finding the best setting starting with “Low”. Many planars have low impedance but require higher current to perform properly.

With the selector set to “Mid”, the 6.3 mm headphone output can also be used to connect 16-Ω stereo speakers, driven at around 5 watts. High sensitivity is recommended (e.g. >94 dB). This feature highlights 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" (6.3 mm). Other controls include the touch-sensitive standby button, volume knob, impedance selector, and input selector.

The input selector offers three options: RCA IN1, RCA IN2 (unbalanced) and XLR IN3 (balanced, left/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). The rear panel provides a pair of RCA pre-outs and a pair of XLR connectors for balanced pre-out. Output level is controlled by the volume knob.

Electrical design

At the input you’ll find an Alps RK27 potentiometer, followed by a two-stage preamp using CV-181 tubes and Jantzen Superior Z-cap coupling capacitors. The output stage uses 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. Power tubes are DC-heated, with a dedicated circuit separating the heater supply from the audio-path power supply. The high-voltage (anode) supply is solid-state and based on MOSFET devices and low-noise current sources.

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

The amplifier is built in point-to-point technology. All wired connections are UPOCC single-crystal copper 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