Elekit TU-8888 Monoblock Push-pull Power Amplifier kit

The TU-8888 Monoblock PP Power Amp kit is Elekit's latest creation. Sold as a pair, they provide a truly dynamic and detailed sound with a serious kick with enough power to drive any loudspeaker out there. As with all Elekits, the design is amazing, and construction is straightforward, following their pictorial formatted instructions.

It features the high-end LL3733, specifically designed and manufactured by the highly regarded Swedish firm Lundahl Transformers. 

The TU-8888 is compatible with medium-sized tubes like the 6550, KT88, KT90 and larger output tubes such as the KT120, KT150 and KT170 (with a maximum anode dissipation of approximately 35W or higher), allowing you to explore variations in sound quality. Using a pair of KT170 will deliver 60Ws RMS.

Each monoblock has a single RCA / phono socket input. A physical stepped volume control can adjust the input level to match both monoblocks' input sensitivity easily.

When fitting the output tubes, the bias needs to be set up. This is quickly done via two trimmer pots on the top plate. The meter display facilitates this process.

When adjusting the bias (Ip1 + Ip2 ADJ.), larger tubes, which excel in high power output, deliver better sound quality when set near the upper limit of the meter’s green zone. In contrast, medium-sized tubes should be adjusted to a range between the lower limit and the centre of the green zone for optimal performance. Experimenting with different tubes to discover their sound profiles is one of the true joys of using tube amplifiers.

Always turn OFF the power before installing or removing tubes.

The kit can operate from 100Vac, 115Vac, 220Vac and 230Vac 50/60Hz, so it can be used anywhere in the World. It has a frequency response of 10Hz - 50Khz, with an incredibly low noise floor at 50uV RMS. Please see the information sheet for more specifications.

In the TU-8888, the cathode bypass capacitors, which significantly influence the sound quality, are super low ESR conductive polymer aluminium electrolytic capacitors. Replacing these capacitors indiscriminately may degrade sound quality.

The coupling capacitors (C3, C5, and C6) in the TU-8888 also significantly determine sound quality. The capacitors provided are non-inductive polypropylene film capacitors capable of handling radio frequencies. ELEKIT considers these components high quality, so their replacement may not produce noticeable effects. However, some audiophiles may prefer experimenting with alternative capacitors.

The TU-8888 PCB is designed with additional space to accommodate larger capacitors. If you decide to replace the coupling capacitors, ensure that the new components meet the following specifications:

• Rated voltage: Higher than 450V
• Capacitance: C3: 0.1µF // C5 and C6: 0.47µF

The TU-8888’s output transformer features a dedicated NFB winding, isolating the speaker output from the amplifier circuitry and chassis ground (GND). This unique design makes connecting the outputs in series possible—an option not available with standard amplifiers. The maximum output power can be doubled by connecting the outputs in series compared to a single amplifier.

Essential Considerations for Series Connections:

1. Ensure that the same signal (identical phase and level) is input to both amplifiers.
2. Use the output terminal with an impedance value equal to half the impedance of the speaker you plan to use. For example:
   1. For an 8Ω speaker, use the 4Ω outputs of the amplifiers.
   2. For a 16Ω speaker, use the 8Ω outputs of the amplifiers.

Features:

• The design supports use of various types of beam output tubes, such as octal-base (US 8-pin) beam tubes, from KT88 to KT170.
• The output transformer is the LL3733, specificaly designed and manufactured by the highly regarded Swedish firm, Lundahl Transformers.
• The manner of speaker connection ensures the speaker output is isolated from both the amplifier circuit and the chassis ground.
• An adjustable input level control is provided at the rear of the chassis.
• Every precaution has been taken to eliminate hum including the use of a proven MOSFET ripple filter and DC power ON of the voltage amplifying tube heater circuit.
• Multiple protective measures are employed using fuses and PTCs.
• In TU-8888, the bias is set manually, and an easy adjustment is made using the meter provided.

Even more details can be found in the booklet below.

Sold as a pair. Kit not sold with valves or IEC lead.

PRICE (pair)
£1900.00 +vat +p&p