Усилители для наушников — Feliks Audio ECHO CLASSIC

The Echo Classic is a desktop valve headphone amplifier handcrafted in Poland by Feliks Audio and positioned by the maker as an entry point into its tube range. It follows an output transformerless, or OTL, circuit in a simplified construction without extra features, with a list price of EUR 749.

Key specs that matter

The circuit runs on four valves, a pair of 6N1P driver tubes and a pair of 6N6P power tubes, and the stock set uses new old stock samples of both types. Output power is 350 mW and gain is 20 dB, with an input impedance of 100 kohm. Frequency response is 15 Hz to 45 kHz within 3 dB. Distortion is quoted as 0.4% into 300 ohm at 20 mW. Feliks Audio lists an optimal headphone impedance range of 80 to 600 ohm, and the only headphone output is a 6.3 mm jack. The chassis measures 26.8 x 21.7 x 11.8 cm and weighs 3.5 kg.

Engineering and use context

Current for the valves is drawn from a custom stabilised toroidal transformer, and the supply adds electronic ripple suppression to keep hum out of the audio stages. The amplifier sets its own bias automatically, so the owner can swap the 6N6P and 6N1P valves for other compatible tubes without adjusting anything afterwards. The unit is sold in versions for 230 V or 120 V mains, and the package holds the amplifier complete with its four tubes, a power lead, printed instructions and the warranty paperwork. The compact metal chassis carries a black top plate with wooden side panels, and the analog signal arrives through a pair of RCA sockets at the rear. The valves stand exposed on the top plate, which means the amplifier needs open space above it rather than a closed shelf. In an OTL layout the power valves feed the headphones directly with no output transformer in between, which explains why the maker aims the Echo Classic at higher impedance headphones where the current demand is lower.

Pairing

The stated impedance range points toward dynamic headphones with medium or high impedance, such as studio and home models, and away from low impedance planar designs. Any line level source with an analog output, for example a DAC or a streamer, can feed it. Because the Echo Classic has only a single large jack output, headphones with a 3.5 mm plug need an adapter, and balanced headphone cables cannot be used.

Alternatives

The Feliks Audio Euforia Evo is the brand's OTL headphone amplifier with PsVane CV-181 driver valves and XLR and RCA headphone outputs.