It utilizes a high sound quality 4” full range speaker unit made up of a high reproduction traditional paper-pulp cone and powerful magnetic system, which has been improved and strengthened.
Repeated tests were carried out to obtain the optimum vented box. Tests were also conducted on various types of tube amplifier in order to choose the best one to go with the 4” full range speaker unit. The 6BQ5 tube that was selected is small, but, despite its size, is almost equal in performance to larger tubes. Also, an output transformer and electric power transformer have been developed to enable optimum drive of speaker units by the 6BQ5 tube.

koro-2013A uses technology that was established decades ago. Why? It’s not because we’re sentimental, nor because we have an absolute belief in tube technology. koro-2013A is simply the result of our desire to create an equipment with minimum circuit configuration that will not only give maximum musical enjoyment, but also last a lifetime.
koro-2013A is not mass-produced, but handmade by Japanese craftspersons. Some may say that hand-soldering is an inefficient way of making things in today’s world. However, we believe that this is the best method. Compared to modern print circuit boards, it ensures that capacitance, reactance and other factors that adversely affect the quality of sound are reduced to a minimum level.
koro-2013A is manufactured to provide the purchaser with decades of use. For this reason it does not use specialized, expensive components. If the tube, chemical capacitor, volume control or any of the other parts wear out, they can easily be replaced. koro-2013A is of simple construction, made from components available on the general market. For these reasons the equipment can be maintained by a non-specialist.
koro-2013A has an audio quality and technical durability that, like the music it reproduces, transcends the ages.

The specification of koro-2013A :
A205A Integrated tube amplifier
Input* :
Output* :
Output tubes :
Input tube :
Output Transformer :
Output power :
Total gain :
Frequency :
Distortion :
Power Consumption :
AC Input power :

Weight :
Dimension :
100mV 100Ω x 1
8Ω screw/plug connection x 1
EL84(6BQ5) Pentiode mode A1 Single-End
ECC83(12AX7) Twin Triode x 1
10w x 2
4.8w/ch at 1.4V input 500Hz/8Ω/ch
12Hz - 70kHz/-3dB
0.75% 0.01w/10kHz
117V±10V 50/60Hz 1 Phase
Installed power cable.
7.0 kg
(W)285 x (H) 125 x (D)230mm

M13A Tall-boy speakers
Speaker Unit:
Rated Power Input:
Maximum Power input:
Weight :
Dimension: Speaker
Dimension: Pedestal
MDF Piano finish vented box x 2
4” Magnetically Shielded driver 1 unit
Paper pulp cone with Rubber surround

88dB 1W/1m
7.5 kg
(W)170 x (H) 855 x (D)135mm
(W)240 x (H) 18 x (D)205mm

Package Price for koro-2013A: $1,500
Option: Amplifier safety cover $150