Oguzhan’s Burson Conductor 3X GT with Sennheiser HD 660S

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Sales Burson
August 13, 2024

Post Info

Feedbacks - Conductor GT3 | GT4
KEF LS50 Wireless II, Sennheiser HD 660S

This product has already exceeded my expectations, and I’m excited to see how it will perform with a 5A power charger and upgraded op amps. I’m curious to hear if these enhancements will take its performance to an even higher level.

The System

Listening with

Sennheiser HD 660S · Headphones: open-back, dynamic, circumaural · discontinued

Impedance: 150 Ω
Sensitivity: 104 dB SPL @ 1 kHz, 1 V (as published) ≈ 95.8 dB/mW (calc.)
Frequency response: 9 Hz – 41.5 kHz (AU page); 10 Hz – 41 kHz (user manual)
Plugs / cables supplied: 6.35 mm unbalanced and 4.4 mm balanced cables (user manual)
Other: THD <=0.04% (1 kHz, 100 dB); max input 500 mW

Matching notes: At 150 Ω and 104 dB/V, the HD 660S is a high-impedance load that needs voltage more than current: about 2 V (27 mW, 13 mA) for 110 dB SPL (calc.). Burson rates the Conductor 3X GT at 1.3 W (XLR) / 0.65 W (SE) into 150 Ω, which is about 14.0 V / 9.9 V RMS (calc.), roughly 17 dB / 14 dB more than that. The Conductor 3X GT’s 0.5 Ω headphone output impedance is 1/300 of the load. ^{[1] [2] [3] [4] [5] [6]}

Burson

Burson Conductor 3X GT · DAC / headphone amplifier / preamp · discontinued

Output power (XLR / SE): 16 Ω 10 W / 5 W · 32 Ω 8 W / 4 W · 100 Ω 3.8 W / 1.9 W · 150 Ω 1.3 W / 0.65 W · 300 Ω 0.64 W / 0.32 W
Output impedance: 0.5 Ω (headphone); 1 Ω (pre out); 25 Ω (DAC out)
Output voltage: RCA 2 V (DAC out)
Gain: High / Low; dB not published
Inputs: 2x XLR; 2x RCA; USB (XMOS; PCM to 768 kHz/32-bit, native DSD512); Toslink; coaxial (24/192); Bluetooth 5.0 aptX HD; microphone
Input impedance: 40 kΩ
Input sensitivity: line level
Outputs: XLR/RCA pre / DAC out; subwoofer pre out; 6.35 mm + 4-pin XLR headphone
DAC / chipset: 2x ESS ES9038 (suffix not stated)
Other: Model R-181X (“GT3”); THD <0.0015%; FR ±1 dB 0-58 kHz; 24V/5A PSU

^{[4] [5] [6]}

Also in the system

KEF LS50 Wireless II · Speakers: active wireless bookshelf, two-way (Uni-Q), Class D LF / Class AB HF

Frequency response: 45 Hz – 28 kHz (±3 dB, EQ-dependent)
Connectors: HDMI eARC; optical; coaxial; analogue; Ethernet; Wi-Fi; Bluetooth (primary speaker)
Other: max SPL 108 dB

^[7]

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.