Available to demo at Elise Studio
MASS-Kobo Model 475
Available to demo at Elise Studio
MASS-Kobo Model 475

Out of stock - Accepts Pre-Orders

Out of Stock - Allows Pre-Orders

Message us in discord or our website chat to find out pre-order time.

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MASS-Kobo Model 475

Hand-made Full-Balanced Portable Headphone Amplifier

Balanced output of model 475 is not compatible with unbalanced headphones and earphones.

Unbalanced headphones or earphones connected to the balanced output with or without adapters may cause the amplifier to malfunction.

NEVER connect them to the balanced output. Please use 3.5 mm unbalanced output for unbalanced headphone or earphones
Regular price $2,633.00
Sale price $2,633.00 Regular price
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MASS-Kobo Model 475

MASS-Kobo Model 475

The full balanced headphone amplifier model 428, which has gained popularity since its release, now features an upgraded external DC power supply terminal. The previous USB micro B has been replaced with the more advanced USB Type-C, offering improved connectivity.

For enhanced reliability, the input and output terminals for the Balanced connection utilize Pentaconn connectors manufactured by Nippon Dicks Co., Ltd. These connectors are known for their high quality and robustness. Additionally, all internal substrates are directly connected without the use of cables, and the connectors themselves are gold-plated. These design choices contribute to improved sound quality.

These amplifiers are equipped with a convenient mode change-over switch, allowing you to connect both balanced and unbalanced output players. This versatility enables compatibility with a wide range of audio devices.

Both models also feature the output gain-changing switch, which has been well-received in our flagship model 406. With this switch, you can now enjoy listening to all types of headphones and earphones, whether they have dynamic or balanced-armature drivers, using a single amplifier.

When powered by alkaline AA batteries, the amplifier can provide approximately 4 hours of usage time. Please note that the actual battery life may vary depending on the condition and type of batteries used.

Alternatively, you have the option to power the amplifier by connecting a power bank to the USB Type-C terminal. It's important to note that the amplifier does not have a charging function or digital input/output capabilities when powered in this manner.

Technical specifications

Model
Full-Balanced Portable Stereo headphone amplifier
Power Supply
AA Alkaline or rechargeable battery x 4
External Power Supply
Micro USB +5v
External Power Supply
  • 0.19A (battery 6V, No signal) 0.21A (rechargeable battery, 4.8V No signal) 0.21A (USB 5V, No signal)
  • 0.28A (battery 6V, 1/8 Output) 0.32 A(rechargeable battery, 4.8V, 1/8 output) 0.31A(USB 5V, 1/8 Output)
  • 0.49A (battery 6V, Maximum Output) 0.61A (rechargeable battery), 4.8V, Maximum Output) 0.58A (USB 5V, Maximum Output)
Frequency Characteristics
20Hz - 20kHz (-1dB)
Noise Level
Less than 40μV (in the minimum volume position, 32Ω loaded) Less than 150μV (in the maximum volume position, 32Ω loaded)
Dimensions
97mmW x 132mmD x 40mmH
Weight
440g (with batteries), 382g (without batteries)
Balanced
Unbalance
Input
φ4.4 TRRS x 1
φ4.4 TRRS x 1
Output
4.4 TRRS
φ3.5 TRS
Maximum Input Level
+16dBm
+10dBm
Balanced
Unbalance
P-P
7V (with 32Ω loaded, 1kHz, THD+N 0.05%)
3.5V (with 32Ω loaded, 1kHz, THD+N 0.05%)
RMS
2.3V (with 32Ω loaded, 1kHz, THD+N 0.05%)
1.2V (with 32Ω loaded, 1kHz, THD+N 0.05%)
Maximum Output without Distortion
165mW (with 32 ohm load, 1kHz, THD+N 0.05%)
45mW (with 32 ohm load, 1kHz, THD+N 0.05%)

Shipping and Returns

Dispatch
1–3 business days In-stock items, Monday to Friday except bank holidays, subject to stock and security checks.
Delivery
Tracked or signed Delivery options and costs are shown at checkout. We don't profit from shipping charges.
Returns
14 days For electronics such as DACs, amps and players, in like-new condition with all original packaging and accessories.

Good to know

  • Return shipping is paid by the customer.
  • Open box, B-stock, refurbished and clearance items can't be returned.
  • Please add a valid phone number at checkout in case we need to verify your identity.
Shipping policy Returns policy Contact us

Warranty

New products
1-year manufacturer warranty Most products. The exact warranty is set by the manufacturer.
Pre-owned & open box
3 months B-grade, open box, refurbished, ex-demo and second-hand items.
Covered
Defects in materials, parts and workmanship
Not covered
Accidents, misuse and unauthorised repairs Including abnormal conditions, deliberate abuse and operator error.
Making a claim
Send it to us, we ship it back free You cover shipping to Elise Audio; we pay to send the repaired or replacement product back.
Warranty policy Terms of service Contact us

The full balanced headphone amplifier model 428, which has gained popularity since its release, now features an upgraded external DC power supply terminal. The previous USB micro B has been replaced with the more advanced USB Type-C, offering improved connectivity.

For enhanced reliability, the input and output terminals for the Balanced connection utilize Pentaconn connectors manufactured by Nippon Dicks Co., Ltd. These connectors are known for their high quality and robustness. Additionally, all internal substrates are directly connected without the use of cables, and the connectors themselves are gold-plated. These design choices contribute to improved sound quality.

These amplifiers are equipped with a convenient mode change-over switch, allowing you to connect both balanced and unbalanced output players. This versatility enables compatibility with a wide range of audio devices.

Both models also feature the output gain-changing switch, which has been well-received in our flagship model 406. With this switch, you can now enjoy listening to all types of headphones and earphones, whether they have dynamic or balanced-armature drivers, using a single amplifier.

When powered by alkaline AA batteries, the amplifier can provide approximately 4 hours of usage time. Please note that the actual battery life may vary depending on the condition and type of batteries used.

Alternatively, you have the option to power the amplifier by connecting a power bank to the USB Type-C terminal. It's important to note that the amplifier does not have a charging function or digital input/output capabilities when powered in this manner.

Model
Full-Balanced Portable Stereo headphone amplifier
Power Supply
AA Alkaline or rechargeable battery x 4
External Power Supply
Micro USB +5v
External Power Supply
  • 0.19A (battery 6V, No signal) 0.21A (rechargeable battery, 4.8V No signal) 0.21A (USB 5V, No signal)
  • 0.28A (battery 6V, 1/8 Output) 0.32 A(rechargeable battery, 4.8V, 1/8 output) 0.31A(USB 5V, 1/8 Output)
  • 0.49A (battery 6V, Maximum Output) 0.61A (rechargeable battery), 4.8V, Maximum Output) 0.58A (USB 5V, Maximum Output)
Frequency Characteristics
20Hz - 20kHz (-1dB)
Noise Level
Less than 40μV (in the minimum volume position, 32Ω loaded) Less than 150μV (in the maximum volume position, 32Ω loaded)
Dimensions
97mmW x 132mmD x 40mmH
Weight
440g (with batteries), 382g (without batteries)
Balanced
Unbalance
Input
φ4.4 TRRS x 1
φ4.4 TRRS x 1
Output
4.4 TRRS
φ3.5 TRS
Maximum Input Level
+16dBm
+10dBm
Balanced
Unbalance
P-P
7V (with 32Ω loaded, 1kHz, THD+N 0.05%)
3.5V (with 32Ω loaded, 1kHz, THD+N 0.05%)
RMS
2.3V (with 32Ω loaded, 1kHz, THD+N 0.05%)
1.2V (with 32Ω loaded, 1kHz, THD+N 0.05%)
Maximum Output without Distortion
165mW (with 32 ohm load, 1kHz, THD+N 0.05%)
45mW (with 32 ohm load, 1kHz, THD+N 0.05%)
Dispatch
1–3 business days In-stock items, Monday to Friday except bank holidays, subject to stock and security checks.
Delivery
Tracked or signed Delivery options and costs are shown at checkout. We don't profit from shipping charges.
Returns
14 days For electronics such as DACs, amps and players, in like-new condition with all original packaging and accessories.

Good to know

  • Return shipping is paid by the customer.
  • Open box, B-stock, refurbished and clearance items can't be returned.
  • Please add a valid phone number at checkout in case we need to verify your identity.
Shipping policy Returns policy Contact us
New products
1-year manufacturer warranty Most products. The exact warranty is set by the manufacturer.
Pre-owned & open box
3 months B-grade, open box, refurbished, ex-demo and second-hand items.
Covered
Defects in materials, parts and workmanship
Not covered
Accidents, misuse and unauthorised repairs Including abnormal conditions, deliberate abuse and operator error.
Making a claim
Send it to us, we ship it back free You cover shipping to Elise Audio; we pay to send the repaired or replacement product back.
Warranty policy Terms of service Contact us

Customer reviews

Customer Reviews

Based on 3 reviews
67%
(2)
0%
(0)
0%
(0)
33%
(1)
0%
(0)
C
CA
Beware of the Open-Box Very Limited Warranty

Sadly and very annoyingly, shorty after the three month limited warranty ran out on this amp, the left channel started to lose some volume. Not a lot, but extremely noticeable. I have to raise the volume on that channel to balance it out. It really soured the experience. With this open-box costing around $1500 after the shipping fees, it's pretty ridiculous for it to fail.

It's a shame, as this thing sounds incredibly unique. It sounds like a tube amp, while having more detail than a lot of solid state amps. But it presents that detail in a very relaxed and misty way.

All of that is kinda out the window since this started to fail so quickly. I'm not sure if these aren't made very well, or if I just had very bad luck.

Be very aware that this amp's warranty is only three months with it being open-box. I can't say this thing is worth a base price of nearly $1800 brand new either though. This should not have happened.

R
Rakesh Patel
First class service from Elise Audio

First class service from Elise Audio. The item arrived promptly and in superb condition. Meet them at CanJam2025 where they introduced this amp. And it is a perfect pairing with my DAP and IEM. Recommend them to anyone looking for high end hifi help

H
H.C.

Fantastic amplifier. If you have both iem and over ear headphones, andyou're trying to find an amplifier for them, then this is the one you should get. I pair it with fiio q7 and it really scales up the sound, both iems and over ear headphones. In low gain, it has a very clean sound, so you won't hear any tiny background noise even with the most sensitive iem. When turned to high gain, it can drive over ear headphones very well. Overall, it's a fantastic and well made portable amplifier.

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