Tokyo Hy-Power RF Linear Amplifiers

Solid State RF Linear Amplifier Engineering  

1.8 MHz ~ 28 MHz HF AMPLIFIER (160m~10m)
Detailed Views and Specifications
HL-2.5Kfx HF Amplifier

  • Small Footprint

  • Light weight- lightest 1.5kW amplifier in its class

  • Internal Power Supply

  • Automatic band change when used with most modern transceivers… Icom, Kenwood and Yaesu

  • Amplifier incorporates an advanced 16bit Microprocessor that controls all the functions of the amplifier, including the protection circuits.

  • Lower cost in replacing finals compared to replacing tubes in tube-type amplifiers.

  • When properly configured truly “ONE BUTTON OPERATION”. No tuning, waiting, or selecting bands…Just select a frequency and transmit!



The HL-2.5Kfx
was the flagship amplifier of the THP line of HF amplifiers for 5 Years and was to be replaced in 2014 by the HL-2500Fx. It is a full legal limit amplifier with a minimum output of 1.5kW (1.2 KW on 28 MHz), operating on bands from 160M-10M. The very first 2.5Kfx were actually developed in a semi kit form and later a early production model appeared that looked slightly different from the final model.

The amplifier incorporates a pair of ARF 1500 RF Mosfets that are easily capable of supplying the required output power, they are mounted on a very large solid copper heatsink. It also includes a built-in power supply and operates with line voltages of 200v-250v ONLY. The operating voltage of the amplifier can be fine tuned (via transformer tap settings) to the line voltage present at the operator’s station for maximum efficiency.

It should be noted that in late 2011 THP reworked parts of the amplifier and changed one of the boards. The firmware was upgraded to Ver 1.5E This upgrade made the amplifier litteraly bullet proof and was tested by shorting the output with a screwdriver at full output and no damage occured. THP also limited the 10M output to approx 1Kw as the 10M band was too stressful on the mosfets when some hams tried to use them at legal limit on 10M.

The HL- 2.5Kfx is designed to integrate fully with the Tokyo Hy-Power HC-1.5KAT Automatic Antenna Tuner. The HL-1.5KAT Tuner band switching will auto-synchronize to the 2.5Kfx amplifier band setting (manual or automatic mode), following whatever band is selected on the amplifier. Most third party automatic tuners will also function properly, when used with the HL-2.5Kfx. Of course manual tuners can also be used, though band selection and antenna tuning must be done manually and carefully by the operator.

There is a front mounted LCD screen that displays current band setting. In addition the LCD will display any faults encountered by the amplifier. There are also two front mounted meters. One meter continually displays the power (forward) output. The second meter is selectable via the front mounted meter switch. It can display Power Reflected (Pr), Idle voltage to the MosFets (Vd), Transmitting Current of the MosFets, and ALC voltage.

Additional front mounted controls include an automatic/manual band switch to select the mode of band switching, and a rotary band selector switch to change the bands while in manual band switch mode. To round out the front panel also installed are 4 LED indicators On Air, Fan Fault, Id/High current and Protection/Fault indicator.

Rear controls include ALC adjustment control, DB15 switching band data connector, HL-1.5KAT Tuner Interface DIN socket, Exciter (Radio) input, antenna output, PTT keying line (STBY) RCA jack and a ALC RCA jack.

The amplifier is QSK capable (50wpm+) using miniature high speed Panasonic relays for T/R switching.

Due to its efficient externally mounted fan and an internal power supply, the HL-2.5Kfx is the smallest, lightest amplifier in its class.

Included with the amplifier are the necessary cables to connect the unit to most Icom, Kenwood, and Yaesu radios. This will allow full automatic operation between the radio, amplifier, and antenna tuner. Other radios also have to be successfully integrated, though not currently supported by Tokyo Hy-Power, including Flex Radio, Elecraft, and TenTec Radios.

Cables for these radios are available from third party sources. There are also some third party devices that will fully integrate the HL-2.5Kfx with any modern radio containing a RS-232 port. The amplifier will also synchronize 100% with the Fluid Motion SteppIr controller. The amplifier will follow the same band that is selected by the radio/controller.

Frequency Band 1.8MHz ~ 28MHz (160m ~ 10m)
(All Amateur HF Bands & WARC)
Operating Modes SSB/CW
(RTTY - Reduced duty cycle 5Min)
Typical RF Drive
(full output)
85W typical - 100W Max
Output Power 1.5kW Minimum SSB/CW
1.8kW PEP Typical
1.2kW - 28Mhz
1kW - RTTY 5 Minutes
Amplifier Class Class AB Push – Pull Circuit
RF Power Transistors Microsemi ARF 1500 x 2

Operating parameters:
120V@30A max
Band Switching
Icom, Kenwood, Yaesu, and Elecraft K3 Transceivers.
Power Requirement 200VAC-250VAC
50/60Hz – 3000VA
Cooling Method Forced Air Cooling
T/R Switching Miniature High Speed Relays
(Panasonic / 5-6 ms)
Size 12.8W x 5.7H x 15.9D
Weight 57.3 lbs
Production Period 2008 - 2013 (closure point)

Open PDF File Manual

The Last Firmware Version Sold was Ver 1.5E it should be noted that this firmware version was used to compliment a couple of hardware upgrades. The firmware has been successfully copied from these chips. Just keep in mind that just because a 2.5Kfx amp may bootup saying ver 1.5E that does not mean it also had the hardware modifications done. I will try to post pictures of the newer and older boards on the forum.

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