We are pleased to announce another exceptional tube amp kit from Elekit. Our previous kit, the Elekit TU-8300R 300B, was a huge success and sold out far quicker than we ever expected. See our build report on the previous kit here. Indulge yourself in the satisfaction of accomplishment that comes from knowing you built a tube amplifier with your own hands!
The Elekit TU-8600 is a Single Ended DIY Stereo Tube Amp Kit. Always in pursuit of great sound quality beyond the typical 300B amp, Elekit have updated and improved the amplification, power, and feedback circuitry with this new design. The result is an amplifier with amazing sound quality and super low noise, that can also be used with headphones. Incredibly, the noise level is as low as 1/10 of TU-8300R.
TUBES ARE NOT INLCUDED IN THIS KIT. Tube sets for this kit can be ordered below.
■ Power circuit enhancement A high efficiency, low magnetic flux leakage R-core is used. The rectifier consists of schottky barrier diodes that require shorter recovery time. This results in a reduction in even negligible noise spikes. The windings of the power transformer include individual windings for the filament heater(A- Power), high voltage (B-power), and bias to stabilize the Negative Feedback (NFB) circuitry(C-Power). In addition, all power is stabilized to reduce residual noise as much as possible. This results in the noise level as low as less than 1/10 of that of TU-8300R.
■ Stable NFB circuit for great audio quality To make the most of the 300B tubes, the characteristics of various parts and circuits, including OPT, have been improved. The NFB is applied to the cathode of the 300B by the third winding of the OPT as well as to the voltage amplifying stage. Consequently, the overall NFB is minimized as well as the chance for the transient response.
■ New active automatic bias adjustment adopted For the 300B tube bias, the power supply is equipped separately, and a ”New active automatic bias” is used where the amp detects plate current and automatically adjust the grid voltage. This design earns TU-8600 the priviledges of both self-bias and fixed bias. In addition, current detecting circuit is moved from the cathode side to the B-power side resulting in even better sound quality.
■ Driving 300B tubes to full power A very orthodox design is used for the voltage amplifying stage to bring out the outstanding characteristics of the famed 300B tubes. Of special note is that 12AU7(ECC82) is used in parallel for the 2nd stage to drive the 300B tubes to full power- resulting in 200Vp-p without clipping.
■ Tube-friendly design Warm-up time for directly-heated and indirectly-heated tubes largely differ. In most designs, amp power-up starts heating both the directly heated 300B tubes (fast warm-up) as well as the indirectly-heated 12AU7 and 12AX7 (slower warm-up). In TU-8600, the 300B tubes are heated after the indirectly-heated tubes have warmed up. A very tube-friendly design that will not overload tubes that have not warmed up fully.
■ Output level selection for headphones For the headphone, you have 4 selections of output level to match your headphone.
■ Ample space for larger coupling capacitors Capacitors can have a big effect on sound. TU-8600 uses high quality conductive polymer hybrid electrolytic caps and polypropylene film caps. For those who wish to use other higher quality caps, there is ample space provided on the PCB for mounting larger caps.
■ Safety tube cover
Vacuum Tube Stereo Power Amplifier Tubes Required: 300B x 2, 12AX7 x 1, 12AU7 x 2 (Not included. Order full tube sets here)
Output Stage: 300B tubes, Class A single ended, active bias adjustment
Voltage Amplification Stage (Input stage): 12AX7 (ECC83), 12AU7 (ECC82)
Heater/Filament Power: DC voltage (LDO used)
Plate voltage: MOSFET + BJT ripple filter (for Left and Right separately)
Rated Output (8ohm load, THD 10%): 9.2W + 9.2W
Rated Input: 320mV rms
Frequency response (-3dB): 7Hz - 40,000kHz
Residual noise (IHF-A, 8ohm load): 36μVrms
Inputs: 1 Line input (RCA)
Output Terminal: Gold-plated speaker binding terminal (Banana plug)
Headphone Impedance: 8-600ohm , unbalanced
Power Voltage: 110-120V AC OR 230V AC 50/60Hz
Power Consumption: 90W
Dimensions: W385 x H217 x D325
Weight: Approx 12Kg
Elekit (EK Japan Co. LTD) has been producing electronics kits
since the early 1970's. While their main focus has always
been educational kits, more recently they started to offer
hifi audio amplifier kits. Included are some fantastic DIY
vacuum tube amps and headphone amplifiers.
Since this is an electronic product that is assembled by the user, we cannot provide a warranty like those found for regular pre-assembled electronics. Instead, Elekit can provide a counseling service. If there is a problem in the product please contact ELEKIT. However, throughout the instruction manual there are many check points, and we kindly ask you to make sure to pay attention to those check points as most of the time your problem can be solved if you follow them closely.
We can not accept returns of any kit that has been started.
EK JAPAN CO., LTD
Tofuro-minami 2-19-30, Dazaifu-shi, Fukuoka, 818-0105 Japan