Усилители для наушников — TOPPING A900

The A900 is a fully balanced headphone amplifier and preamplifier from TOPPING, the Chinese maker of DACs and amplifiers, with the model code TP138 in its A Series. It appeared around 2025 and shares the RC23 remote control with the D900 DAC, switching between the two devices by pressing both keys. The A Series also includes the A90 Discrete headphone amplifier.

Key specs that matter

From the balanced outputs, at below 0.1% THD+N, the A900 delivers 22 W per channel into 16 ohm, 14 W into 32 ohm, 7 W into 64 ohm, 3 W into 150 ohm, 1.5 W into 300 ohm and 750 mW into 600 ohm. The single-ended outputs deliver 6 W into 16 ohm and 3 W into 32 ohm. THD+N at 1 kHz is below 0.00004% at 500 mW into 32 ohm and below 0.00003% at 80 mW into 300 ohm. Both S/N and dynamic range measure 151 dB balanced and 143 dB single-ended, crosstalk is -153 dB balanced and output impedance is below 0.1 ohm. Frequency response is 20 Hz to 40 kHz ±0.05 dB. Inputs are three balanced XLR and 6.35 mm TRS combo sockets, and headphone outputs are two 6.35 mm jacks, one three-pin XLR, two 4.4 mm and two four-pin XLR sockets, plus an XLR preamplifier output with 100 ohm output impedance and THD+N below 0.000055%. The A900 measures 330 x 57 x 200 mm, weighs 2.62 kg and draws less than 11 W.

Engineering and use context

Three gain settings give -0.1, 10.3 and 19.8 dB balanced, or -6.1, 4.3 and 13.8 dB single-ended, with input sensitivities of 22.0, 7.0 and 2.1 V RMS. The lowest setting keeps noise very low for sensitive in-ear monitors, and TOPPING measured residual noise below 0.3 µV RMS balanced at low gain. Maximum output voltage reaches 60 V peak to peak balanced. Volume steps can be set to 0.5 or 1 dB, a safe-volume mode limits the starting level, two presets store settings, and volume can be remembered per output or per input. A 2 inch LCD shows normal, VU meter or FFT screens, controlled by touch buttons, a multifunction knob or the remote. The 12 V trigger input and output switch the A900 on together with the D900 or other equipment. The number of outputs means different headphones can stay connected at the same time.

Pairing

The TOPPING D900 DAC is the intended source, connected through balanced XLR and controlled by the same remote. With its high power and very low output impedance, the A900 suits every headphone above 8 ohm, whether sensitive in-ears or hungry planar designs.

Alternatives

The TOPPING A90 Discrete is the headphone amplifier from the same A Series with a discrete circuit.