model 404 Full Balance Portable Headphone Amp.

Discontinued 26.July.2019

All the products by Mass-Kobo are made to order.

This price is the only case to ship overseas.Payment is prepaid. (I produce it after you have paid)

Tariff and Ship cost not included.
You are obligated to pay VAT to receive goods.

Delivery time is one month from 2 weeks.

To pay by PayPal, you need to add 5% of the total amount.
Pyapal account :


This amplifier provides you with the highest sound also by Balance Headphone.

The sound is similar to model394 or model395 since those use similar circuit and same part as model394 and model395.

Use Manual(English ver.)

<Specifications> (Batt. 9V or USB 5V)

Model : Full Balance Portable Stereo headphone amp
Input : φ3.5 TRS x 1(Unbalance) , φ2.5 TRRS or φ3.5 TRRS x 1(Balance)
Output : φ3.5 TRS x 1 (Unbalance for Dinamic HP) , φ2.5 TRRS or φ3.5 TRRS x 1(Balance for Balanced Armature IEM) , XLR4 x 1(Balance for Dinamic HP)
Maximum Input Level : +16dBm(Balance) , +10dBm(Unbalance)
Maximum Output Level (P-P) :7 V(Balance) , 3.5V(Unbalance) (with 32Ω loaded, 1kHz, THD+N 0.5%)
               (RMS):2.3V(Balance) , 1.2 V(Unbalance) (with 32Ω loaded, 1kHz, THD+N 0.5%)
Maximum Output without Distortion 165mW(Balance) , 45mW(Unbalance) (with 32Ω load, 1kHz, THD+N 0.5%)
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)
Power Supply : Battery : AA Alkaline or Rechargable Battery x 6
External Power Supply : Micro USB +5v
Consumption Current : 0.13A(Battery 9V , No signal) 0.14A(Recharger Battery , 7.2V No Signal) 0.21A(USB 5V , No Signal)
               0.27A(Battery 9V , Maximum Output) 0.33A(Recharger Battery , 7.2V , Maximum Output) 0.7A(USB 5V , Maximum Output)
Size : 113mmW x 155mmD x 40mmH
Weight : 650g (with Battery) , 515g(without Battery)