Introduction to KT88 Electronic Tube:

The Orsefon team tested various brands of KT88 tanks, but still unanimously agreed that the original factory sound of the Mackintosh is warmer, and the large dynamic output is not disorderly and has a stronger sense of hierarchy. Therefore, they spared no expense in making a one-to-one replica, with a structure completely identical to the original Mackintosh factory.

Original factory bile

Internal diagram of Gaole Fengdan

Gaole Fengdan

The KT88 series beam power quadrupole has an anode maximum dissipation power of 42W. In audio amplifiers, two electronic tubes can achieve a power of 75W when used as AB1 push-pull outputs, and KT88-T can also be used in electronic voltage stabilizing circuits. KT88-T is similar to 6550 and can be used interchangeably.

Filament heating

First gate resistance

At self bias

Pa+Pg2 ≤ 35W 0.47 MO

Extreme rated value

Anode voltage 800V

When Pa+Pg2>35W 0.27 MO fixed bias voltage

Second gate voltage 600V

Pa+Pg2 ≤ 35W 0.22 MO

First gate voltage- 200V

Anode dissipation power 42W

Interpolar capacitance

Second gate dissipation power 8W

Quadrode connection method and transistor connection method

Anode plus second gate dissipation power 46W

Input capacitance 169.3PF

Cathode current 230mA

Flagship version

Product parameters:

Product name: 6TH generation Taiwan flagship version ORSEFON MC275

Output impedance group: 4 Ω/8 Ω/16 Ω

Output power:

Stereo mono 75W

Channel bridging method 150W

Tube model: Selected KT88 vacuum tube*4; Selected 12AX7 vacuum tube*3; Selected 12AT7 vacuum tube *4

Frequency response: 10Hz-50kHz

Harmonic distortion: 0.5%

Signal to noise ratio: 》98dB

Input sensitivity: 400mV

Fuse specification: fast dissolving 250V3-4A; Size: 6 *30 or 6 * 32

Power supply voltage: 220V/110V, manually adjustable (original factory shipped 220V)

Overall size: 410 * 360 * 230mm (length * width * height)

Product Usage: It can be used as a power amplifier or as an integrated amplifier by inputting RCA audio cable; XLR balanced input can only be used as a power amplifier, and needs to pre amplifier

The sixth generation flagship version has a comprehensive upgrade in its overall appearance, with the volume adjustment button placed in the front terminal and the back terminal for more versatile use. It has added an additional set of inputs and added a black technology purification system. For the first time, it has added customized 1:1 bile ducts, upgraded circuit boards and components. After user feedback and continuous trial and error, it has spared no cost to develop a sound that can achieve over 90% of the original version, constantly breaking new definitions. The strongest version has been launched

The customized replica KT88 high-power RF transistor for the flagship version is a right characteristic transistor. Unlike left characteristic power transistors such as 300B845, the gate operates at positive voltage and has gate current. The left characteristic power transistor operates at a negative voltage with no gate current and is relatively easy to design. However, the right characteristic electronic transistor reduces input impedance interference due to the presence of gate current, making it easy to use high-power driving. The left characteristic transistor only needs voltage driving. If the customized KT88 electronic tube MC-275 needs to output a maximum undistorted Class A power of 75 watts, it requires a certain amount of power to drive. Generally, it uses a transistor or a high transconductance collector four stage transistor, and the pentade is connected to a transistor for driving. It is also useful to drive a transformer. The customized bladder design is just enough to overcome this noise and noise, so as to better and stably play the taste of the bladder.

The KT88 series beam power quadrupole has an anode limit dissipation power of 42W. In audio amplifiers, when two vacuum tubes are used as AB1 push-pull outputs, a power of 75W can be obtained, and KT88-T can also be used in electronic voltage stabilizing circuits. KT88T is similar to 6550 and can be used interchangeably.

Filament heating

UH ------6.3V

IH ------1.6 A

Ultimate rating

Anode voltage -800V

Second gate voltage -600 V

First gate voltage -200V

Anode dissipation power -42 W

Second gate dissipation power -8 W

Anode plus second gate dissipation power -46W

Cathode current -230 mA

First gate resistance

At self bias

Pa+Pg2 ≤ 35W0.47 M Ω

Pa+Pg2>35W0.27 M Ω

At fixed bias, Pa+Pg2 ≤ 35W 0.22 M Ω

Pa+Pg2>35W 0.10 M Ω

Interpole capacitance

Tetrode connection method

Input capacitance -169.3PF

The Soul of Transformer and Machine

The sixth generation flagship version basically adds a purification module system in the fifth generation, and everyone knows that transformers are one of the most important parts of the bile machine. The winding method and material of transformers are of utmost importance. The reason why the mcintosh bile machine stands out for generations is its unique multi wire parallel winding transformer technology; The replica mcintosh 275 has three combinations, one for the power supply and two for the output. A team of experienced Taiwanese enthusiasts has spared no effort in using up to sixteen units (the original MCintosh 275 is a twelve house) UP0C0 (single hydrogen free copper) for grouping and winding. The purity of the single copper free product can reach 99.99, reaching a high level. After each cow is wrapped, it will undergo freezing treatment, After low-temperature treatment of the metal, the low-temperature treatment of the conductor can disrupt the crystal arrangement, recombine molecules, and macroscopically make the metal harder. This type of transformer has the advantages of good broadband response and extremely low distortion, which is similar to the effect of a MCintosh transformer. Due to the high cost of materials, which weigh up to 25KG, three transformers account for two-thirds of the weight. With such meticulous material selection, winding, and special freezing treatment, the power of the stereo can reach 75W on one side, and 150W on a single channel in series, equivalent to 800W of a stone machine. If the huge thrust is strong and stylish, but still retains a smooth texture of a vacuum tube machine, it has an open and wide sound field, and listening to large-scale orchestral music is particularly exciting. You can easily feel the distinct layers of voice, the undulating dynamics in the music, the thick and full sound base, and the rich and strong low-frequency, making the music full of power and vitality

Flagship version with purification module output transformer

The sixth generation flagship version upgraded the purification transformer and added a purification system while maintaining sufficient power, creating a new frequency conversion mode based on the output frequency of 400Hz (8 times the frequency). The frequency is changed once in each cycle of the output AC voltage, such as the first cycle being 50Hz, the second cycle being 120Hz, and the next cycle returning to 50Hz... This increases the originally limited number of switchable frequencies to 20, And move the frequency switching time point from the beginning of a waveform cycle to the midpoint of the cycle. The change in switching time point is effective in reducing transformer electromagnetic leakage and humming

Automatic adjustment of vacuum tube bias

There is a problem with the sixth generation flagship bias technology electronic vacuum tube machine, which is the need to adjust the bias voltage of the vacuum tube. If the power tube needs to be replaced, the bias voltage adjustment is even more inevitable. The traditional bias adjustment involves measuring the value with an electric meter and then using a screwdriver to turn the screw. Later on, some manufacturers made progress by building measurement circuits and displaying the current bias status with light signals or screen values, making it more convenient to adjust the bias voltage. However, for many consumers, it is necessary to check the bias condition later and slowly turn to the correct position after changing the pipe. When it comes to adjusting the bias voltage, one needs to heat up the machine. After the machine has been running for at least half an hour and the pipes are all hot, adjusting the bias voltage is accurate. So it seems that it's still troublesome. Using a self-designed automatic bias voltage adjustment circuit, not only do you have to worry about the bias voltage running away after a long time, but it is also more convenient to replace the tube. If you want to replace any pipes, simply replace them and turn them on. This 275 will adjust the bias voltage to the correct value on its own. This design is completely from the perspective of consumers, making it more convenient to use, even when buying a tube machine for the first time, it is reassuring. This technology was developed by a Taiwanese team after several years of research, while other 275 products on the market do not have this feature.