Alejandro’s Burson Funk with KEF LS50 and beyerdynamic Amiron

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Sales Burson
June 25, 2021

Post Info

Feedbacks - Funk
beyerdynamic Amiron, Burson Funk, Burson Swing, KEF LS50

At first, the Funk (speaker output) sounded a bit shy, but with burn-in time it has opened up excellent soundstage and dynamics. Quite impressed with the headphone amplifier since the beginning

The System

Listening with

KEF LS50 · Speakers: bookshelf, two-way bass reflex (Uni-Q) · discontinued

Impedance: 8 Ω (minimum 3.2 Ω)
Sensitivity: 85 dB (2.83 V / 1 m)
Frequency response: 79 Hz – 28 kHz (±3 dB); 47 Hz – 45 kHz (-6 dB)
Recommended amplifier power: 25 – 100 W
Other: max output 106 dB; 7.2 kg; crossover 2.2 kHz

Matching notes: The KEF LS50 is rated at 85 dB (2.83 V / 1 m) into 8 Ω nominal (3.2 Ω minimum). Burson rates the Funk at 35 W into 8 Ω and 45 W into 4 Ω. At that rating the speaker would reach about 100 dB SPL at 1 m (calc., one speaker, before room gain). KEF recommends 25 – 100 W amplifiers. ^{[1] [2] [3] [4]}

beyerdynamic Amiron Home · Headphones: open-back, dynamic (Tesla), circumaural

Impedance: 250 Ω
Sensitivity: 102 dB SPL (1 mW / 500 Hz) ≈ 108.0 dB/V (calc.)
Frequency response: 5 Hz – 40 kHz
Plugs / cables supplied: detachable double-sided 3 m cable, 3.5 mm plug with 6.35 mm adapter

Matching notes: At 250 Ω and 102 dB/mW, the beyerdynamic Amiron Home is a high-impedance load that needs voltage more than current: about 1.3 V (6.3 mW, 5 mA) for 110 dB SPL (calc.). Burson does not publish a 250 Ω rating for the Funk. Its 150 Ω and 300 Ω ratings (0.4 W SE; 0.15 W SE) fall either side of it. The Funk’s under 2 Ω headphone output impedance is less than 1/125 of the load. ^{[5] [2] [3] [4]}

Burson

Burson Funk · Headphone amplifier / integrated amplifier

Output power (headphone): 16 Ω 3.5 W · 32 Ω 2.5 W · 100 Ω 0.6 W · 150 Ω 0.4 W · 300 Ω 0.15 W
Power: 8 Ω: 35 W · 4 Ω: 45 W
Output impedance: <2 Ω (headphone)
Gain: not published
Inputs: RCA L/R
Input impedance: 38 kΩ
Outputs: headphone (SE); speaker terminals
Other: Model P-300; THD <0.03%; FR ±1 dB 0-35 kHz; speaker S/N 92.5 dB

^{[2] [3] [4]}

Burson Swing · DAC / preamp · discontinued

Output impedance: 15 Ω (pre out)
Output voltage: RCA not published
Inputs: USB; Toslink; coaxial
Outputs: RCA pre out; RCA DAC out
DAC / chipset: ESS SABRE32 ES9038 (suffix not stated)
Other: THD <0.002%; DAC ch. sep. 132 dB

^[6]

Specs from manufacturer data unless a source below says otherwise. “calc.” values are worked out from those figures (V = √(P × R); 110 dB SPL used as a loud reference level). Gear listed without specs is not in our spec library yet.