ELEKIT TU-8900 2A3/300B (Stereophile Review Available NOW - July 2023 Edition)

Price US$1945.00 (Ll2785C amorphous core OPT)

Stereophile Reveiw : July 2023 Edition


Stereophile Class A Components​


This is our first time to offer Amorphous core OPT. I want to make sure the Lundahl amorphous core is superior than the regular C Core.
This is the sample of Amorphous Core for TU-8900.. Amorphous core requires a longer burn in time..
Is it better??

No Takman for this model - Takman is running out of material to make 2% carbon resistors.

COSSOR/Linlai Delux 2A3 + Sylvania 12BH7A $380
COSSOR/Linlai Blackplate 300B +Sylvania 12BH7A $345
COSSOR/Linlai WE300B +Brimar 12AU7 $$695
Western Electric WE300B (5 Years Warranty) + Sylvania 12BH7A

COSSOR/LINLAI Delux metal base 2A3 $285
Sylvania 12BH7 $95 (pair)
Brimar 6067/12AU7 $159 (pair)

If you buy TU-8900 with LL2785C and Western Electric 300B, the Cossor/Linlai Delux 2A3 is free

COUPLING CAPS 100nF 450V x 2 (VCAP CuTF $195
Cossor/Linlai WE2A3

46 x Audio Note Tantalum Resistors $5.25 each
4 x Takman 2% (3.3ohm and 8.2 ohm)
2 x AMTRANS 1% AMRG (15 ohm 2W) $9.50 each
2 x Audio Note Silver 0.1 600V $345 each
2 x Acrylic Bracket (to secure the silver caps) Free with Silver Cap

LEFT - TU-8600S (Metal Tube Cover and metal knob), RIGHT - TU-8900 (Plastic Tube Cover, plastic knob) https://www.flickr.com/photos/64593884@N08/ https://www.flickr.com/photos/64593884@ https://www.flickr.com/photos/64593884@N08/

https://flic.kr/p/2majMQN https://www.flickr.com/photos/64593884@N08/

Matching headphone impedance/volume levels.

You can change the headphone impedance/volume levels by
simply removing the front panel and change the position of a
short pin.

Directly-heated triode tubes like the 300B and 2A3 enjoy an enduring popularity among audiophiles. The 300B with its rich midrange and extended bass- and 2A3 with its delicate expression and gentle tone offer a very special sonic experience. These 2 tubes are similar in appearance but very different in characteristics and can both be used in TU-8900 without any special changes in amplifier settings. Many manufacturers are producing 300B and 2A3 tubes so users can enjoy trying the various versions available from different vendors. *

Automatic detection of 300B and 2A3 tubes
“300B” and “2A3” tubes look similar but their respective filament voltage and operating parameters are totally different. Their supply voltages need to be adjusted depending on which of these tubes are used in the same amp. In TU-8900, the tubes that are installed are detected automatically and the correct filament voltage and voltage of B-power are automatically set. When 300B tubes are installed- the LEDs on the sides of the volume knob will light up in blue. If 2A3 tubes are installed- the volume knob LEDs will light up in green. Additionally- these LEDs on the right and left side of the volume knob will turn red when there is excessive current due to defective tubes, etc., and the current is shut down to protect the amp. The red LEDs will also diagnose the problematic tube- the right side of the volume knob turns red when excess current occurs in the right channel, and vice versa.

■ Tube-friendly design
Warm-up time for directly-heated tubes and indirectly-heated tubes are different. In most designs, directly-heated tubes warm up faster than indirectly-heated tubes- so often directly heated tubes are often overloaded. With TU-8900, the voltage is gradually raised and reduces the level of overload to the directly-heated tubes.

12BH7A instead of 12AU7
TU-8900 is designed to use 12AU7 as voltage amplifying tubes. However, 12BH7A, with high driving ability, can also be used instead of 12AU7.

Ample space for larger coupling capacitors
Coupling capacitors can have a big effect on the sound quality. For the TU-8900, high quality conductive polymer electrolytic caps and polypropylene film caps are provided. However, exchanging for other coupling capacitors is also possible. The maximum size of the caps that can fit in the space is 22mm in diameter x 44mm in length.

Matching headphone impedance/volume levels
You can change the headphone impedance/volume levels by simply removing the front panel and change the position of a short pin.

Newly designed circuitry
The power transformer has independent windings for the right and left channel to minimize the interference between channels as much as possible. The filament power uses the latest DC-DC converter for extremely low noise and high efficiency. Schottky barrier diodes and fast recovery diodes are used as rectifying diodes that reduces even the most negligible noise spikes. Listeners can enjoy music free from noise even when using a pair of high efficiency headphones. The main circuit of the power unit is unitized per channel as a module.

Easily change the feedback setting to NON-NFB
Many triode tube amps use negative feedback in their design. The TU-8900 has an option for listeners to hear the triode tube sound without negative feedback. In TU-8900, changing the position of a short plug on the PCB can change the setting to NON-NFB. The gain level increases by approx. 8dB when NON-NFB setting.

Updated more reliable tube sockets
After brainstorming with our vendor, we have come up with a more reliable 4-pin sockets for 300B/2A3. Tubes are mounted safely and securely when installed in these sockets.

High heat-resistant polycarbonate tube cage
The IEC (International Electrotechnical Commission) sets guidelines on thermal limits on materials and parts, such as a chassis and the tube cage. The TU-8900 tube cage top can heat up to 100 degrees C due to the heat from the output tubes. A robust polycarbonate tube cage with high heat resistance is used to meet the IEC standard.

Specifications of TU-8900

●Stock tubes  : 300B (or 2A3) x 2pcs, 12AU7 (or 12BH7A) x 2pcs *Tubes not included
* specifications below are with the 300B+12AU7, with NFB, 8Ω loaded
●Rated output : 8W+8W (300B) / 3.5W+3.5W (2A3) <THD 10%>
●Rated input : 1Vrms (300B) / 650mVrms (2A3)
●Residual noise: 15μV (IHF-A)
●Frequency response: 7Hz-90kHz (with NFB) / 12Hz-45kHz (Without NFB)
●Input impedance : 50kΩ
●Output impedance : 4-6.3Ω, 8-16Ω (SW on backside)
●Input terminal : LINE x 1
●Output terminal : Speaker output terminals (L/R channel):Gold-plated screw type terminal (Banana plug usable)
Headphone terminal :6.3mm headphone jack
●Power voltage : AC110-120V or AC220-240V 50/60Hz (3P inlet)
●Power consumption: 95W (300B) / 65W (2A3)
●Measurement : W356xH214xD320mm (including projections)
●Weight : Approx. 11.4kg (excluding a power cable)
●JAN code : 4952682107941

After 200 hours listening, I am confident to offer the Audio Note upgrade option:​

46 x Audio Note Tantalum Resistors $5.25 each
4 x Takman 2% (3.3ohm and 8.2 ohm)
2 x AMTRANS 1% AMRG (15 ohm 2W) $9.50 each
2 x Audio Note Silver 0.1 600V $345 each
2 x Acrylic Bracket (to secure the silver caps) Free with Silver Cap

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Sunvalley SV1616D is a traditional amp design... tube rectifier/choke/...
In fact Sunvalley keeps the same design for more than 20 years...
Mr Ohashi is a musican and audiophile. The amp design is based on sound..

ELEKIT tube amp is not a traditional tube amp design..
ELEKIT is changing the design model by model. The life span of each model is very short except TU-8200 and TU-8500.
Mr. Fujita is not an audiophile..His design is based on spec..
Both are good but they are using different approaches
Hey Viktor,
any view from yourself on how the 8900 sounds compared with the 8600 when running 300B? The 8900 is really interesting, would love to have an amp which can double duty as 300B and 2A3 but really love the pace and rhythm of the 8600 and wouldn't want to lose that. thanks.
I love the design of Elekit and a low wattage 2A3 amp will be great, As Nelson Pass says "first watt is important". I am sure the 2A3 will be a killer once paired with the AER BD2 drivers.

Victor, Please consider that I would want to purchase the TU- 8900, let me know when you are expecting to take orders and delivery dates.