EXPERT 1.5K-FA TAURUS is a solid-state linear amplifier from the Italian manufacturer SPE (Società Per l'Elettronica), designed as a fully automatic terminal unit for HF and 6 m bands. The device covers the range 1.8 to 50 MHz including WARC bands and, where legally permitted, also the 5 MHz (60 m) bands.
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Advantages of the EXPERT 1.5K-FA TAURUS amplifier
The output stage uses a pair of LDMOS transistors, each with a dissipation of 1.8 kW, which ensures high durability, efficiency and linearity. The output power is 1.5 kW, on the HF bands with a tolerance of ±0.5 dB and on 50 MHz with a tolerance of ±0.8 dB. The power is switchable between MAX (full power), MID (1 kW) and LOW (500 W) levels, while the switching can be controlled by the operator or automatically activated by the amplifier protection system. The device does not need any warm-up time and is immediately ready to transmit.
The dimensions of the amplifier including connectors are 28 × 12 × 38 cm (W × H × D) and the weight is approximately 9.5 kg. At this size, the amplifier integrates a switched power supply with power factor correction (PFC) and a fully automatic antenna tuner, making it one of the most compact solutions in its performance class.
The amplifier is controlled by two powerful processors that process extensive software code responsible for automating the band, antenna, tuner and protection functions. Thanks to this, during normal operation, the operator simply turns the transceiver's tuning knob or clicks on a spot in the DX cluster - the amplifier switches the band, selects the antenna and adjusts the tuner.
Built-in antenna tuner
The automatic tuner handles antenna impedance mismatches up to 5:1 SWR on HF bands and 2.5:1 on 6 m at full power. The amplifier allows software control of up to four antenna outputs (SO239 connectors) and up to two antennas can be programmed for each band. Band, antenna and tuner settings are switched within 10 ms. In STANDBY mode, the signal is fed directly from the exciter without tuner intervention, so the operator can continuously check the antenna properties without connecting the amplifier to the transmitter. The maximum attenuation caused by the tuner is 0.8 dB and the tuner can be bypassed in software if the operator has an external tuner connected.
In addition to classic antenna connectors, the amplifier also supports the control of SteppIR or tunable antennas. Ultrabeam via a dedicated PORT connector, which automatically monitors transceiver tuning changes and sends appropriate commands to the antenna control unit.
Unique features, remote control and SO2R
Automation via ALC
The amplifier generates its own ALC voltage, which in OPERATE mode automatically regulates the transceiver's excitation power to the optimal level, while in STANDBY mode it passes the full excitation power. The operator does not have to manually adjust the excitation power every time the band or power level changes MAX/MID/LOW. Without an ALC connected, the excitation power must be adjusted manually, otherwise there is a risk of overloading the amplifier input (so-called overdriving).
CAT and BAND DATA support
The amplifier supports direct CAT connection for ICOM, YAESU, KENWOOD, TEN-TEC, FLEX-RADIO and ELECRAFT transceivers, including the older BAND DATA alternative. For cases without an available CAT connection, the amplifier includes an internal frequency counter that can determine the working band during the first transmission, although this option is not recommended as a primary solution.
SO2R – Single Operator Two Radio
The amplifier has two independent inputs (INPUT 1, INPUT 2) for connecting two transceivers, possibly of different brands at the same time, and a separate connector SO2R for the second, usually multi-band antenna. In SO2R racing operation, the operator can work on one band via the first transceiver, while the second transceiver monitors another band via the SO2R antenna. Once the operator registers an interesting multiplier on the second transceiver, he just needs to press its PTT a zosilňovač automaticky prepojí príslušnú anténu na vysielanie, kým prvý transceiver sa prepne na SO2R anténu pre príjem.
To expand the number of antennas from four to six, or to remotely place the antenna matrix, it is possible to use the additional AM-01 Remote Switch unit, which communicates with the amplifier via a single coaxial cable - it simultaneously transmits the RF signal, power supply and control data.
Signal predistortion
On the rear panel there is an SMA connector with 60 dB attenuation, which provides a sample of the transmitted signal. This can be fed into SDR transceivera s príslušným softvérom na korekciu intermodulačného skreslenia (IMD); podľa výrobcu bolo takýmto spôsobom dosiahnuté zlepšenie IMD o 25 dBc a viac, pričom v testoch s konkrétnym SDR transceivrom dostupným na trhu bola nameraná hodnota IMD až -66 dB.
Remote control and firmware update
Via the USB or RS232 ports on the rear panel, the amplifier can be connected to a computer and controlled remotely using the free Term_1.5K_USB or Term_1.5K_232 software. The application displays faithful copies of the front panel display and keyboard, so remote operation has the same range of functions as with physical access to the device. The same data channel is also used to download and install new firmware versions directly from the manufacturer's website.
Two antenna memory banks
The amplifier stores two independent antenna configurations, labeled Bank A and Bank B. This feature is useful for stations with two QTHs or for DXpeditions - when you return home, you can simply switch back to the original memory bank without having to retune the tuner.
QSK and protection system
The amplifier supports full break-in (QSK) thanks to switching relays with gold-plated contacts and control that eliminates the risk of so-called hot switching. The relay settling time is less than 6 ms, which meets the requirements of most current transceivers. The protection system continuously monitors the heatsink temperature, voltage and current of the output stage, reflected power, SWR and maximum RF voltage on the tuner, both in parallel hardware and software. In addition, the thermal management also includes linear fan speed control, which makes the noise during normal operation significantly lower compared to tube amplifiers.
Why buy the EXPERT 1.5K-FA TAURUS amplifier?
The main argument for this amplifier is the degree of automation of the station while maintaining compact dimensions and low weight. The manufacturer emphasizes that the built-in automatic tuner eliminates the need for a separate external tuner, which saves space and cabling in the shack, while also allowing for safe handling of impedance mismatches up to 5:1 without operator intervention.
Very impressive is the test where at the Daytona meeting the amplifier delivered 1.5 kW at 50 MHz in FT8 mode for long hours without the temperature exceeding 60°C. There was also a similar demonstration at the Friedrichshafen 2025 meeting.
The ability to connect two transceivers simultaneously and control up to four (or with the AM-01 system up to six) antennas from a single device simplifies the wiring of a contest or DXpedition station, where multiple separate antenna switches and coaxial distributions would otherwise be required. The dual memory bank feature is useful for operators with two locations or for repeated DXpeditions to the same location.
The low weight (approximately 9.5 kg) and the included carrying bag make the amplifier a practical choice for Field Day, IOTA activations or DXpeditions, where the universal switching power supply (100 - 255 VAC, 47 - 63 Hz) allows connection to various electrical networks without the need to change the transformer.
One user, who compared the amplifier with several competing solid-state solutions before purchasing, described his experience as follows: initially, the transition from a tube amplifier to fully automatic operation required some time to familiarize himself with the settings, but after completing the configuration, the amplifier reliably delivered full power even in digital modes, with the protection circuit responding correctly to his own error in antenna selection.
For designers and technically oriented radio amateurs, the openness of the interface is also interesting - the manufacturer publishes documentation for the serial protocol (the so-called Application Programmer's Guide), which allows the integration of the amplifier into your own logging or control applications beyond the scope of the supplied software.
Videos
The following video captures the EXPERT series amplifiers, including the TAURUS model, at the exhibition Hamvention 2024, where the manufacturer SPE presented its current product line.
Where to buy and warranty
The EXPERT 1.5K-FA TAURUS amplifier is available directly from the manufacturer SPE Società Per l'Elettronica, based in Rome, as well as through a network of authorized distributors for Europe, America, Asia and Oceania, the list of which is maintained by the manufacturer on its official website. According to the manufacturer's price list, the recommended price including ATU is €4450 plus VAT, picked up from the warehouse in Rome (FOB Rome); the specific selling price at individual distributors may vary and SPE is not responsible for the payment terms agreed between the distributor and the customer.
The amplifier is covered by a two-year warranty from the date of invoice, during which authorized distributors in the EU provide free repair of manufacturing defects and replacement of defective components in authorized service centers. The exception is power LDMOS transistors, which are covered by the warranty only for the first three months, in the form of a one-time replacement. The costs of transportation to the service center and back are paid by the buyer in both directions.
The warranty does not apply, for example, to damage caused by improper use, exceeding the power parameters of the connected antennas, insufficiently dimensioned baluns or impedance transformers, repeated alarms for high SWR or input overload, or interference with the device by an unauthorized person. For the warranty to be valid, it is necessary to send the manufacturer a completed registration card within 30 days of purchase.