TOPPING A50s Headphone Amplifier (Apos Certified)

Don’t Look Down

With a THD+N of 0.00007% and SNR of 143dB, the TOPPING A50s’ noise floor is so far down you might get dizzy. Compare this to the original A50, which has a THD+N of <0.0004% and an SNR of 123dB.

The Power Hitter

The TOPPING A50s swings for the fences with its output power, driving a whopping 3,500W x2 @32Ω (more than 1,000mW more powerful than the A50). With that sort of power, you can drive anything from sensitive IEMs to power demanding headphones.

6.35 Single-Ended and 4.4 Balanced Outs

The A50s offers both a 6.35 single-ended and a 4.4 balanced out on its front plate. Both options deliver stellar dynamic range (138dB/144dB) and output impedance (<0.1Ω/0.2Ω).

High-Low Gain Setting

Drive high impedance headphones with ease thanks to the A50s’ high-low gain setting of 0dB/6dB at the SE output and 6dB/12dB at the balanced output.

Specs

• THD+N @1 kHz A-wt
• 6.35mm headphone jack
• <0.00007% @Output=850mW(32Ω)
• <0.00006% @Output=90mW(300Ω)
• 4 4mm Balanced headphone jack
• <0.00007% @Output=3.4W(32Ω)
• <0.00006% @Output=367mW(300Ω)
• THD ©20-20kHz 90kBW
• 6.35mm headphone jack
• <0.0004% @Output=720mW(32Ω)
• <0.0002% @Output=77mW(300Ω)
• 4 4mm Balanced headphone jack
• <0.001% @Output=2.88W(32Ω)
• <0.0005% @Output=307mVV(300Ω)
• SNR @MAX OUT 1 kHz A-wt
• 6.35mm headphone jack: 137dB
• 4 4mm Balanced headphone jack: 143dB
• Dynamic Range @1 kHz A-wt 
• 6.35mm headphone jack: 138dB
• 4 4mm Balanced headphone jack: 144dB
• Frequency Response: 20Hz-200kHz(±0.05dB)
• Output Level 
• 6.35mm headphone jack: 21Vpp
• 4 4mm Balanced headphone jack: 42Vpp
• AP measured noise level @A-wt
• 6.35mm headphone jack
• <0.7uVrms @G=L
• <0.8uVrms @G=H
• 4 4mm Balanced headphone jack
• <0.9uVrms @G=L 
• <1.1uVrms @G=H
• Actual noise level * @A-wt
• 6.35mm headphone jack
• <0.3uVrms @G=L 
• <0.45uVrms @G=H 
• 4 4mm Balanced headphone jack
• <0.6uVrms @G=L 
• <0.95uVrms @G=H
• Channel Crosstalk @ 1kHz
• 6.35mm headphone jack: -86dB
• 4 4mm Balanced headphone jack: -128dB
• IMD CCIF@(18kHz + 19kHz)
• 6.35mm headphone jack: -116dB
• 4 4mm Balanced headphone jack: -116dB
• IMD SMPTE @(60Hz + 7kHz)
• 6.35mm headphone jack
• -110dB, SMPTE4: 1
• -118dB, SMPTE1: 1
• 4 4mm Balanced headphone jack
• -110dB, SMPTE4: 1
• -118dB, SMPTE1: 1
• Input Sensitivity
• 6.35mm headphone jack
• 7.5Vrms @G=0dB
• 3.8Vrms @G=6dB
• 4 4mm Balanced headphone jack
• 7.5Vrms @G=odB
• -3.8Vrms @G=6dB
• Gain
• 6.35mm headphone jack
• 0.0dB @G=0dB
• 6.0dB @G=6dB
• 4 4mm Balanced headphone jack
• 6.0dB @G=0dB
• 12.0dB @G=6dB
• Output Impedance 
• 6.35mm headphone jack: <0.1Ω
• 4 4mm Balanced headphone jack: <0.2Ω
• Output Power THD+N<1%
• 6.35mm headphone jack
• 1.4W x 2 @32Ω
• 192mW x 2 @300Ω
• 4 4mm Balanced headphone jack
• 3.5W x 2 @32Ω
• 760mW x 2 @300Ω
• Output Power @2Vrms 
• 6.35mm headphone jack
• 485mW x 2 @32Ω
• 52mW x 2 @300Ω
• 4 4mm Balanced headphone jack
• 1950mW x 2 @32Ω
• 208mW x 2 @300Ω
• Load Impedance
• 6.35mm headphone jack: >8Ω
• 4 4mm Balanced headphone jack: >8Ω