EL34 Push-pull Tube Amp Kit [ TU-8340 ]

EL34 Push-pull Tube Amp Kit
Model number TU-8340
Price JPY 129,800 (incl.tax)
[JPY 118,000 (excl.tax)]
Tools required
Phillips screwdriver ,Diagonal cutter ,Longnose pliers ,Pen knife ,File ,Tweezers ,Soldering iron


Notice with regard to the use of KT150 tubes for TU-8340

****************************** THIS PRODUCT IS NO LONGER AVAILABLE. ******************************

Limited production model for 2016 Winter

EL34 Push-pull Tube Amp Kit TU-8340 adopted "Semi-automatic bias adjustment system" - which allows users to adjust the bias simply by pressing buttons even if the model takes on the fixed bias method - no need of manual adjustment every time of tube rolling. Thus safe and simple bias adjustment is realized - a dream feature for tube lovers.

■Semi-automatic bias adjustment system - Adjust the bias by simply pushing a button!

TU-8340_モジュール.jpgCommonly there are 2 methods of bias adjustment - fixed-bias and self-bias.
For AB-class push-pull amp, fixed-bias is more effective and advantageous since
each power tube can be adjusted for bias. The drawback with the fixed bias method is each tube needs to be checked and adjusted for bias manually one by one.
In addition, if user fails to adjust the bias correctly, tubes or the amplifier itself could get damaged. This “Semi-automatic” bias adjustment system inporporates fixed-bias method but with no manual ateps other than a simple push of button. The tube bias settings are managed by a microcontroller that adjusts the tube bias in less than a minute - very unique and innovative system that EK JAPAN is introducing into the
tube audio market. The bias adjustment module is preassembled - users just need
to install it onto the PCB and it is ready to use.

<How to adjust the bias>


1. When using new tubes or tubes are exchanged, press “SAFETY
RESET” button right after the power ON. The cathode current of the output tubes are brought to the minimum position - safe statuts - and it becomes stand-by status.

  1. 2. After the tubes fully warm up, press “START ADJUST” button. Then the bias current is automatically adjusted.
  2. This adjustment is stored in the nonvolatile memory. Therefore, even though the output tubes are exchanged and the power is turned ON, the error indication appears until “SAFETY RESET” button is pressed.

    Supports various output tubes

    Semi-automatic bias adjustment system supports 6L6GC series (KT66, etc), KT88 series (6551, KT90, etc), as well as the default EL34 series (6CA7, KT77, etc) tubes. In addition, the robust power transformer can support tubes with higher heater current requirements such as the KT88 series including KT120 and KT150. These features allow users to experience different sounds by changing tubes.
    Tube rolling.jpg

■2 types of amplifier mode

In TU-8340, Ultra-LInear connection and Triode connection are selectable with the MODE switch at the rear side of the model for your to enjoy the sound difference by the operation of the ouput tubes. Although the maximum output will be smaller in Triode mode than in UL mode, the sound quality must delight the Triode fans.
Rear side.jpg

■Ample space for upgrading to larger coupling capacitors

Coupling capacitors are one of those that affect the sound. For TU-8340, the PCB is designed with ample
space around them, so that users can exchange those coupling capacitors with different ones of larger size.
* Maximum size : 57mm in length x 31mm diameter


■Universal Power Transformer

Supporting 4 different voltages - 100V, 115V, 200V, and 230V are selectable upon assembly.

■Thorough countermeasures for hum noise and improved separation

For B-power, well-established ripple filters by the power MOSFET are adopted for the voltage amplifying stage, output tube stage, and both channels separately for B-power to reduce the hum noise and improve the separation.


Stock tube
EL34x4, 12AT7x4
Rated output
UL connection

Triode connection

EL34 45W+45W 24W+24W
6L6GC 32W+32W 18W+18W
KT88 42W+42W 24W+24W
KT150 50W+50W 28W+28W
Rated input

EL34 (UL) : 460mV  (Triode) : 360mV 

Residual noise
EL34 (UL) :180μV (IHF-A)
Frequency response
5Hz-120kHz (-3dB)

Input terminal

LINE x 1
Output terminal
SP output terminal (4-6.3Ω, 8-16Ω) Gold-plated terminal (Banana plug usable)
Power voltage
AC100V 50/60Hz (3P inlet)
Power consumption
EL34 130W (no signal) 190W (Max. output)
KT88 140W (no signal) 195W (Max. output)
KT150 150W (no signal) 250W (Max. output)
W450 x H200 x D336mm (incl.projections)

Approx, 17kg (incl. cover, excl. power cord)

News & Support