At the top of Topping’s highly regarded A-series, the A90 is a headphone amplifier with few rivals. Capable of functioning as both a headphone amp and a preamp, this flagship unit is outfitted with NFCA (Nested Feedback Composite Amplifier) modules, which work together with ultra-high-gain feedback technology for impressive AC and DC control. Its high-current capabilities make it a great choice for low-impedance headphones, while its 145-decibel dynamic range and 0.2uV noise rating are ideal for more sensitive IEMs. Other notable specs include an output impedance less than 0.1 ohms, a THD+N rating less than 0.00006 percent, and a two-channel 7,200-milliwatt maximum power output. Choose from three gain settings and a 4-pin XLR, 4.4-millimeter balanced, or 6.35-millimeter single-ended port. Switch to preamp mode and connect the A90 to a power amp or DAC such as the D90 to drive active speakers.

**Topping A90 (Headphone Amp) – Single-Ended Input / Output**

- THD + N at 1 kHz (A-weighted): < 0.00007% at 500 mW (32 ohms) / < 0.00006% at 80 mW (300 ohms)
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0004% at 500 mW (32 ohms) / < 0.0001% at 80 mW (300 ohms)
- SNR at maximum output 1 kHz (A-weighted): 141 dB
- Dynamic range at 1 kHz (A-weighted): 141 dB
- Frequency response: 20 Hz – 40 kHz (± 0.05 dB)
- Output level: 9 Vpp at G = L, 25 Vpp at G = M, 25 Vpp at G = H
- AP measured noise level (A-weighted): < 0.7 uVrms at G = L, < 0.7 uVrms at G = M, < 0.9 uVrms at G = H
- Actual noise level (A-weighted):< 0.2 uVrms at G = L, < 0.2 uVrms at G = M, < 0.6 uVrms at G = H
- Channel crosstalk at 1 kHz: -106 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -9.5 dB at G = L, 0 dB at G = M, 9.5 dB at G = H
- Output impedance: < 0.1 ohms
- Output power: 3,300 mW x 2 at 16 ohms (THD + N: < 0.1 %), 2,000 mW x 2 at 32 ohms (THD + N: < 0.1 %), 250 mW x 2 at 300 ohms (THD + N: < 0.1 %), 125 mW x 2 at 600 ohms (THD + N: < 0.1 %)
- Load impedance: > 8 ohms

**Topping A90 (Headphone Amp) – Balanced Input / Single-Ended Output**

- THD + N at 1 kHz (A-weighted): < 0.00009% at 500 mW (32 ohms) / < 0.00006% at 80 mW (300 ohms)
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0004% at 500 mW (32 ohms) / < 0.0001% at 80 mW (300 ohms)
- SNR at maximum output 1 kHz (A-weighted): 137 dB
- Dynamic range at 1 kHz (A-weighted): 137 dB
- Frequency response: 20 Hz – 40 kHz (± 0.01 dB)
- Output level: 9 Vpp at G = L, 25 Vpp at G = M, 25 Vpp at G = H
- AP measured noise level (A-weighted): < 0.7 uVrms at G = L, < 0.7 uVrms at G = M, < 0.9 uVrms at G = H
- Actual noise level (A-weighted):< 0.2 uVrms at G = L, < 0.2 uVrms at G = M, < 0.6 uVrms at G = H
- Channel crosstalk at 1 kHz: -102 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -9.5 dB at G = L, 0 dB at G = M, 9.5 dB at G = H
- Output impedance: < 0.1 ohms
- Output power: 3,300 mW x 2 at 16 ohms (THD + N: < 0.1 %), 2,000 mW x 2 at 32 ohms (THD + N: < 0.1 %), 250 mW x 2 at 300 ohms (THD + N: < 0.1 %), 125 mW x 2 at 600 ohms (THD + N: < 0.1 %)
- Load impedance: > 8 ohms

**Topping A90 (Headphone Amp) – Single-Ended Input / Balanced Output**

- THD + N at 1 kHz (A-weighted): < 0.00007% at 500 mW (32 ohms) / < 0.00006% at 80 mW (300 ohms)
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0004% at 500 mW (32 ohms) / < 0.0001% at 80 mW (300 ohms)
- SNR at maximum output 1 kHz (A-weighted): 145 dB
- Dynamic range at 1 kHz (A-weighted): 145 dB
- Frequency response: 20 Hz – 40 kHz (± 0.05 dB)
- Output level: 18 Vpp at G = L, 49 Vpp at G = M, 49 Vpp at G = H
- AP measured noise level (A-weighted): < 0.9 uVrms at G = L, < 0.9 uVrms at G = M, < 1.4 uVrms at G = H
- Actual noise level (A-weighted):< 0.6 uVrms at G = L, < 0.6 uVrms at G = M, < 1.3 uVrms at G = H
- Channel crosstalk at 1 kHz: -105 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -3.0 dB at G = L, 6 dB at G = M, 15.5 dB at G = H
- Output impedance: < 0.2 ohms
- Output power: 7,600 mW x 2 at 16 ohms (THD + N: < 0.1 %), 6,400 mW x 2 at 32 ohms (THD + N: < 0.1 %), 1000 mW x 2 at 300 ohms (THD + N: < 0.1 %), 500 mW x 2 at 600 ohms (THD + N: < 0.1 %)
- Load impedance: > 8 ohms

**Topping A90 (Headphone Amp) – Balanced Input / Output**

- THD + N at 1 kHz (A-weighted): < 0.00009% at 500 mW (32 ohms) / < 0.00006% at 80 mW (300 ohms)
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0004% at 500 mW (32 ohms) / < 0.0001% at 80 mW (300 ohms)
- SNR at maximum output 1 kHz (A-weighted): 138 dB
- Dynamic range at 1 kHz (A-weighted): 138 dB
- Frequency response: 20 Hz – 40 kHz (± 0.01 dB)
- Output level: 18 Vpp at G = L, 49 Vpp at G = M, 49 Vpp at G = H
- AP measured noise level (A-weighted): < 0.9 uVrms at G = L, < 0.9 uVrms at G = M, < 1.4 uVrms at G = H
- Actual noise level (A-weighted):< 0.6 uVrms at G = L, < 0.6 uVrms at G = M, < 1.3 uVrms at G = H
- Channel crosstalk at 1 kHz: -102 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -3.0 dB at G = L, 6 dB at G = M, 15.5 dB at G = H
- Output impedance: < 0.2 ohms
- Output power: 7,600 mW x 2 at 16 ohms (THD + N: < 0.1 %), 6,400 mW x 2 at 32 ohms (THD + N: < 0.1 %), 1000 mW x 2 at 300 ohms (THD + N: < 0.1 %), 500 mW x 2 at 600 ohms (THD + N: < 0.1 %)
- Load impedance: > 8 ohms

**Topping (A90 Preamp) – Single-Ended Input / Output**

- THD + N at 1 kHz (A-weighted): < 0.00006%
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0001%
- SNR at 1 kHz (A-weighted): 141 dB
- Dynamic range at 1 kHz (A-weighted): 141 dB
- Frequency response: 20 Hz – 40 kHz (± 0.05 dB)
- Output level: 9 Vpp at G = L, 25 Vpp at G = M, 25 Vpp at G = H
- AP measured noise level (A-weighted): < 0.7 uVrms at G = L, < 0.7 uVrms at G = M, < 0.9 uVrms at G = H
- Actual noise level (A-weighted):< 0.2 uVrms at G = L, < 0.2 uVrms at G = M, < 0.6 uVrms at G = H
- Channel crosstalk at 1 kHz: -106 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -9.5 dB at G = L, 0 dB at G = M, 9.5 dB at G = H
- Input impedance: 20 ohms

**Topping (A90 Preamp) – Balanced Input / Single-Ended Output**

- THD + N at 1 kHz (A-weighted): < 0.00006%
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0001%
- SNR at 1 kHz (A-weighted): 137 dB
- Dynamic range at 1 kHz (A-weighted): 137 dB
- Frequency response: 20 Hz – 40 kHz (± 0.1 dB)
- Output level: 9 Vpp at G = L, 25 Vpp at G = M, 25 Vpp at G = H
- Actual noise level (A-weighted):< 0.2 uVrms at G = L, < 0.2 uVrms at G = M, < 0.6 uVrms at G = H
- Channel crosstalk at 1 kHz: -102 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -9.5 dB at G = L, 0 dB at G = M, 9.5 dB at G = H
- Input impedance: 20 ohms

**Topping (A90 Preamp) – Single-Ended Input / Balanced Output**

- THD + N at 1 kHz (A-weighted): < 0.00006%
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0001%
- SNR at 1 kHz (A-weighted): 145 dB
- Dynamic range at 1 kHz (A-weighted): 145 dB
- Frequency response: 20 Hz – 40 kHz (± 0.05 dB)
- Output level: 18 Vpp at G = L, 49 Vpp at G = M, 49 Vpp at G = H
- AP measured noise level (A-weighted): < 0.9 uVrms at G = L, < 0.9 uVrms at G = M, < 1.4 uVrms at G = H
- Actual noise level (A-weighted):< 0.6 uVrms at G = L, < 0.6 uVrms at G = M, < 1.3 uVrms at G = H
- Channel crosstalk at 1 kHz: -105 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -3.5 dB at G = L, 6.0 dB at G = M, 15.5 dB at G = H
- Input impedance: 40 ohms

**Topping (A90 Preamp) – Balanced Input / Output**

- THD + N at 1 kHz (A-weighted): < 0.00006%
- THD at 20 Hz – 20 kHz, 90kBW: < 0.0001%
- SNR at 1 kHz (A-weighted): 138 dB
- Dynamic range at 1 kHz (A-weighted): 138 dB
- Frequency response: 20 Hz – 40 kHz (± 0.1 dB)
- Output level: 18 Vpp at G = L, 49 Vpp at G = M, 49 Vpp at G = H
- Actual noise level (A-weighted):< 0.6 uVrms at G = L, < 0.6 uVrms at G = M, < 1.3 uVrms at G = H
- Channel crosstalk at 1 kHz: -102 dB
- IMD CCIF at 18 kHz + 19 kHz: -118 dB
- IMD SMPTE at 60 Hz + 7 kHz: -110 dB at SMPTE 4:1 / -115 dB at SMPTE 1:1
- Input sensitivity: < 9.5 Vrms at G = L, < 8.8 Vrms at G = M, < 2.9 uVrms at G = H
- Gain: -3.5 dB at G = L, 6.0 dB at G = M, 15.5 dB at G = H
- Input impedance: 40 ohms