300B SE TUBE AMP KIT [ TU-8600R ]

Model number TU-8600R
Price JPY 118,800 (incl.tax)
[JPY 108,000 (excl.tax)]
Target ageGeneral


Limited production model for 2018

TU-8600, a 300B single-ended tube amp kit released as a limited production model for 2017,
ran out so quickly that we received many requests for reproduction from both domestic and
oversea markets. Upon such request, we reproduced TU-8600 as a revised version TU-8600R
this September, with minimal modification from TU-8600. Limited production, without tubes.

【 TU-8600R features 】

■ 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 system
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-8600R 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-8600R, 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 fully warmed up.

■ Ample space for larger coupling capacitors
Capacitors can have a big effect on sound. TU-8600R uese 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.


■ Output level selection for headphones
For the headphone, you have 4 selections of output level to match your headphone.


■ Safety tube cover included


Stock tube 300Bx2, 12AX7x1, 12AU7x2 
* Tubes are not included.
Rated output 9.2W+9.2W (THD 10%)
Rated input 320mV
Residual noise 36μV (IHF-A)
Frequency response 7Hz-40kHz (-3dB)
Inpur impedance 50kΩ
Output impedance 4-6.3Ω, 8-16Ω (Switch on the back side)
Input terminal LINE x 1
Output terminal

Speaker output terminal : Gold-plated screw type terminal (Banana plug usable)
Headphone output terminal : 6.3mm headphone jack

Power voltage AC100/200V 50/60Hz (3P inlet)
Power consumption 90W
Dimensions W385xH217xD325mm (excl. projections)
Weight Approx. 12.8kg (excl. power cable)




VKMUSIC (Canada) : www.vkmusic.ca

THETUBESTORE (Canada) : www.thetubestore.com

PARTSCONNEXION (Canada) : www.partsconnexion.com

TUBEDEPOT (USA) : www.tubedepot.com

DIY AUDIO STORE (USA) : www.diyaudiostore.com


THLAUDIO : www.thlaudio.com


getAudio (Poland): www.getaudio.com


CNAMUSIC : www.cnamusic.com


RolfSigristSoundDesign : www.rolfsigrist.ch


RFWaves Australia : www.rfwaves.com.au


Please purchase the product from each local dealers.

For those customers who do not purchase the product from each local dealers, we cannot provide any after service, including the English manual data.