Elekit TU-8400 Pentode Single Ended Tube Amplifier kit
The TU-8400 allows you to easily use a variety of major octal-based output tubes. In terms of specifications, it is an intermediate-class model between the TU-8200, which has been well-received for many years, and its big brother model, TU-8850 (limited production model).
It inherits the "Active Auto Bias" function from the TU-8200 and has two power modes, HIGH and LOW. In HIGH mode, it can use the 6L6 series, KT66, KT88, KT90, EL34 (6CA7), 5881, 6550, etc., and since there is a margin in the heater winding of the power transformer, it can also use KT120, KT150, and KT170. In addition, when switching to LOW mode, 6V6 and 6F6 can also be used.
The width and depth of the case are the same as the TU-8200, but the silver base has been replaced with a satin black paint finish, and a safety cover (bonnet) has been added.
The circuit configuration of both the TU-8200 and TU-8400 is a "power amplifier", but the TU-8200 has a two-stage 12AU7 voltage amplification with a slightly higher gain so that it can be used easily without a preamplifier. This is convenient, but Elekit have received feedback that it is a little difficult to use when connecting a preamplifier. Therefore, the TU-8400 has been changed to a single stage 12AX7, making it easier to use when connecting a preamplifier.
However, there are times when you just want to connect a smartphone or a portable powered device and listen to music easily. Therefore, in addition to the RCA jack input on the back,a provided mini jack input on the front, which has a preamp circuit using an op-amp, so you can use it in two ways.
The output tube bias method is the "active auto bias" method, which has evolved over the years in higher-end models since its first use in the original TU-8200. Of course, it can handle a variety of tubes, but the range of tubes that can be used is wider than in the TU-8200 series. First, it supports large tubes. In the TU-8200 series, the current capacity of the heater power supply limited the output tubes to a heater current of up to about 1.6A, that is, KT88 and KT90. In the 8400, the power transformer has been made a size larger, so it can now also use the recently popular KT150 and KT170. However, please note that if you use these tall tubes, the safety cover cannot be attached.
Also, large tubes have the disadvantage of a long warm-up time from when the power is turned on until they start working, so for everyday use, we recommend up to KT88.
On the other hand, it also supports small tubes.
Access to the level switching jumper to match the efficiency of the headphones can be found just by removing the front panel, so it is much easier than the TU-8200.
Can be switched between three types of wiring methods. By replacing the jumper on the board, it is possible to change to ultra-linear wiring, triode wiring, or pentode wiring.
Equipped with a headphone jack The output level can be switched between three levels by replacing the jumper on the board to match the sensitivity of the headphones.
Can be replaced with a larger coupling capacitor The coupling capacitor can be replaced with a larger capacitor of your choice. Please use a capacitor with a maximum diameter of 20mm x length of 36 mm, a capacitance of 0.1 μF, and a voltage of 400Vdc or more.
Please read the full specifications on the datasheet below.
Kit not sold with valves or IEC lead.
E / I output transformer version.
PRICE (1 kit)
£650.00 +vat +p&p