Elekit TU-8850E & TU-8850VK Pentode Single Ended Tube Amplifier kit

Click to Zoom
Elekit TU-8850E & TU-8850VK Pentode Single Ended Tube Amplifier kit

NEW from Elekit, Japan, is the TU-8850E, a stereo single-ended kit that allows you to try various pentode and beam valves. The new kit follows the new, improved front panel and chassis design format of the renowned TU-8900.

It is a big step up from the TU-8200 design that sits in a smaller chassis. The amplifier features an "Active Automatic Bias Adjustment System", making valve rolling simple as you try different valve types. In addition, the amplifier is equipped with a power mode SW at the top panel. Selecting from 3 operation modes, HIGH, MID and LOW, users can try various output tubes. The "SMALL" class of valves are 6L6, 6L6G-GB and WE350B. The "MID" are 6L6GC, 5881, 7581, EL34, 6CA7, KT66 and KT77. The "HIGH" are the KT88, KT90, KT120, KT150, KT170, 6550 and 6550A.

Output tubes operation mode switching system

The Triode connection is accomplished for pentode and beam tubes by connecting the screen grid to the plate. This amplifier has an operation mode SW at the top panel so that users can easily enjoy the sound difference in 2 different modes, UL (Ultra Linear) and Triode modes.

Gain switching jumpers

This is a power amplifier used in conjunction with a preamplifier. However, gain switching is enabled by switching a jumper socket position, and it is possible to connect the amplifier directly to a LINE output of a sound source device without a preamplifier in between.

Headphone noise correspondence

In recent years, various very high-sound-quality headphones and earphones have become available. This amplifier is for those who aspire to enjoy such high-quality sound from a tube amplifier. Thorough countermeasures for hum noise, such as well-established FET ripple filter and DC-power for voltage amplifying tubes, are taken, which realizes a noise-free performance even with high-efficiency speakers. In addition, a headphone level adjustment system is equipped to cope with very high-efficiency headphones and earphones with which a residual noise is easily recognised. A jumper socket can easily adjust the level.

Ample space for larger coupling capacitors

Coupling capacitors can have a significant effect on the sound quality. For TU-8850, high-quality conductive polymer electrolytic caps and polypropylene film caps are adopted. The maximum size of the caps to fit in the space is 22mm in diameter x 44mm in length.

The kit is available in 2 versions. The TU-8500E uses the Elekit E & I output transformers, whereas the upgraded TU-8850VK is supplied with the C-core LL3727 output transformer from Lundahl.


Corresponding tubes

  • Voltage amplifying tube: 12AU7 (ECC82, 6189) x 2pcs
  • Output tube : HIGH mode: 6550, KT88, KT90, KT120, KT150, KT170, etc
  • MID mode: 6L6GD, 5881, 7581, KT66, KT77, EL34 (6CA7), etc
  • LOW mode: 6L6, 6L6G, 6L6GB, WE350, etc

Those of the HIGH mode group tubes can be used in MID and LOW modes, and those of the MID group can be used in LOW mode.
Power mode switch labelled LOW, MID, HIGH.

Output tube operation mode :

  • UL (Ultra-linear connection)
  • TRIODE (Triode connection)

Output tube operation mode switch labelled UL and TRIODE

  • Max. output (8Ω load, THD 10%)
  • [HIGH mode] : 2 x 16W (KT170, UL ), 2 x 13W (KT88, UL ), 2 x 9W (KT88, TRIODE )
  • [MID mode] : 2 x 9W (KT88, UL), 2 x 7.5W (EL34, UL), 2 x 6.5W (KT88, TRIODE)
  • [LOW mode] : 2 x 3.5W (6L6G, UL), 2 x 3W (6L6G, TRIODE)
  • Rated input (HIGH mode, KT88):
  • [UL mode] : 850mV rms (standard NFB), 400mV rms (HIGH-GAIN)
  • [TRIODE mode] : 820mV rms (standard NFB), 450mV rms (HIGH-GAIN)
  • Frequency response : (-3dB, UL, standard NFB): 15-60,000Hz
  • Residual noise : (IHF-A, 8ohm load, standard NFB): 33uV rms
  • Input terminal: 1 x RCA jack stereo
  • Output terminal
  • Speaker output: Binding terminal (Gold-plated, Banana plug compatible)
  • Headphone output: 3-pole standard jack (6.3mm)
  • Speaker impedance: 4 - 16ohm
  • Headphone impedance: 8-600ohm, unbalanced
  • (corresponds to high-impedance headphones as well)
  • Power voltage: AC110-120V or AC220-240V 50/60Hz (3P inlet )
  • Rated power consumption: 115W (HIGH mode, KT170)
  • 80W (MID mode, KT88 )
  • 45W (LOW mode, 6L6G )
  • Dimensions: W356 x H214 x D320mm (incl. projections)
  • Weight: Approx. 11.2kg (assembled, excl. tubes and power cord)


PRICE (1 off, excluding VAT & P&P) not supplied with valves or IEC lead

TU-8850E - £950.00

TU-8850VK (with Lundahl OPTs) - £1310.00



We do offer an upgrade kit. See the list below. These need to be purchased individually. Click on the links and add them to your cart. The total at the time of publishing is £222.32 + vat

CART 15K000B: 15K 0.4W Charcroft Z-Foil Resistor R102, R202 x 2

(REY50-510) - 33K 0.5W TAKMAN Metal Film Resistor R107, R207 x 2

AMRT05-325: 1K 0.5W Amtrans AMRT Resistor R108. R208 x 2

(REY50-370) - 2K2 0.5W TAKMAN Metal Film Resistor R102, R203 x 2

RES-25-05W-33K: 33K 0.5W Audio Note Tantalum Resistor R104, R204 x 2

RES-NM25-05W-220K: 220K 0.5W Audio Note Tantalum Non-magnetic Resistor R106, R206 x 2

AMRT05-505: 33K 0.5W Amtrans AMRT Resistor R109, R110, R209, R210 x 4

(REX50-175) - 51R 0.5W TAKMAN Carbon Film Resistor R116, R216, R117, R217 x 4

S3Q100N: 0.1uF 1000Vdc Solen FEP Tin Foil / Teflon Film Capacitor C102, C202 x 2

ELNAS-165: 1000uF 6.3Vdc Elna Silmic II RFS Electrolytic Capacitor C104, C204 x 2 MOUNT HORIZONTALLY

CAP-100-R-22U-63V: 22uF 63Vdc Audio Note Kaisei POLAR Electrolytic Capacitor C101, C201 x 2

MLAL500-100: 100uF 500Vdc Mundorf MLytic HV Axial Electrolytic Capacitor C110, C210 x 2

CAP-100-STDR-10U-500V: 10uF 500Vdc Audio Note Standard Electrolytic Capacitor C105, C205, C109, C209 x 4

VTB9-PT: Belton B9A 9-pin valve base, PCB mount, gold plated V101, V201 x 2



PDF datasheet

Subscribe to Hifi Collective