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At a glance
- Device type
- Headphone amplifier
- Amplifier technology
- Solid-state
- Headphone outputs
- 4-Pin XLR, 2× 3-Pin XLR, 4.4 mm, 6.3 mm
- Built-in DAC
- No
- Power
- 3.5 W @ 32 Ω (bal.)
Mass-Kobo Model 491
€22,500.00
Tax included
Mass-Kobo Model 491 – hand-built twin-balanced monoblock headphone amplifier from Japan, successor to the Model 465, made-to-order.
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- ✓ 30-day returns · Free return shipping
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At a glance
- Device type
- Headphone amplifier
- Amplifier technology
- Solid-state
- Headphone outputs
- 4-Pin XLR, 2× 3-Pin XLR, 4.4 mm, 6.3 mm
- Built-in DAC
- No
- Power
- 3.5 W @ 32 Ω (bal.)
Why we recommend it
An amplifier built not for the market but for the music: Mr. Masuda hand-builds every Model 491 in Japan and checks each one personally. The twin-balanced monoblock design with two separate power supplies delivers a calm and channel separation we otherwise only know from power amplifiers – and drives even a Susvara as if it were nothing. If you want to hear the difference between very good and final, this is where you hear it. Made to order, and worth the wait.
See all recommendations →Mass-Kobo Model 491
Hand-built twin-balanced monoblock headphone amplifier from Japan
The Mass-Kobo Model 491 is the successor to the acclaimed Model 465 and embodies one of the most uncompromising manufacturing philosophies in headphone amplification: every unit is hand-built in Japan and personally tested and signed off by Mr. Masuda, the founder and designer of Mass-Kobo.
Rather than the conventional stereo circuit found in most headphone amps, the Model 491 uses a twin-balanced monoblock topology with four independent amplifier stages and two fully separate power supplies for the left and right channels — an architecture more commonly found in high-end loudspeaker power amplifiers than in a headphone amp. The result is an exceptionally low noise floor and channel separation capable of driving demanding, power-hungry planar magnetic headphones like the HiFiMAN Susvara to reference-level performance.
The Model 491 offers two balanced XLR inputs and two unbalanced RCA inputs, and covers virtually every common headphone connector with a 4-pin XLR, two 3-pin XLR L/R, balanced 4.4mm and unbalanced 1/4" TRS output. Construction uses lead-free solder throughout, and every unit ships in a rugged Pelican transport case.
As the successor to the Model 465, the Model 491 carries its monoblock concept into a more compact desktop chassis without compromising on noise floor, channel separation or output power. Because every unit is built to order, production numbers are inherently limited.
Pre-order – every unit is hand-built and individually tested in Japan. Lead time: several months.
Technical Specifications
| Type | Twin-balanced monoblock stereo headphone amplifier |
| Inputs | XLR 3-pin balanced × 2, RCA unbalanced × 2 |
| Input impedance | 3.7 kΩ (XLR) / 20 kΩ (RCA) |
| Outputs | XLR 4-pin balanced × 1, XLR 3-pin balanced L/R × 2, 4.4mm balanced × 1, 1/4" TRS unbalanced × 1 |
| Max. output power | ≥ 3.5 W + 3.5 W balanced (32 Ω); 1.8 W + 1.8 W unbalanced |
| Max. output voltage | 10.7 V RMS / 32 V peak-to-peak (32 Ω, 1 kHz, balanced) |
| Residual noise | 90–490 µV, depending on settings |
| Frequency response | 10 Hz – 100 kHz (−0.5 dB); 17 Hz – 50 kHz (−0.2 dB) |
| Dimensions | 330 × 247 × 104 mm |
| Weight | 6.1 kg (unit only) |
| Power supply | AC 100–240 V, 50/60 Hz |
| Made | Hand-built in Japan, made to order |
| Lead time | Several months (pre-order) |
Data sheet
- Device type
- Headphone amplifier
- Amplifier technology
- Solid-state
- Built-in DAC
- No
- Power into 32 Ω
- 3.5 W @ 32 Ω (bal.)
- Headphone outputs
- 4-Pin XLR, 2× 3-Pin XLR, 4.4 mm, 6.3 mm
- Balanced output
- Yes
- Inputs
- 2× XLR, 2× RCA
- Weight
- 6.1 kg