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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Delcon T210 Help

Reviews Summary for Delcon T210
Delcon T210 Reviews: 1 Average rating: 5.0/5 MSRP: $$4000
Description: Delcon T210 is a 3.0-30.0 MHZ grid driven linear amplifier
capable of 1000 watts output. The companion power supply is
the PS210.
Product is not in production.
More info: http://
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N3AJB Rating: 5/5 Feb 28, 2018 19:31 Send this review to a friend
Alpha Amplifier of the 1960s  Time owned: 6 to 12 months
Delcon T210
The Delcon T210 is one of the rarest amplifiers made and is in the ranks of the Heathkit Chippewau, the Eldico 1000, and the Cosmophone 1000, although the Cosmophone was a transceiver with a 1kw input. It was made for the Air Force by Hewlet Packard in 1961 and consists of an RF section and a separate 65 lb power supply. Both the Rf section and power supply are the same size and quite compact, each measuring 7X15X12.
The Delcon T210 was the Alpha amplifier of its day (more advanced design that the Collins 30S-1) consisting of 3 4cx250s in a grid driven, AB1 circuit. The amplifier was rated at 1kw output covering 3.0 to 30 mhz. 15 watts input produces 1kw output. While the amplifier can easily be driven to a 1500 watts output, the IMD most likely would suffer and push 4cx250s to beyond their ratings.
Some of the advanced features of the RF section were vacuum variable plate and load capacitors, a vacuum antenna relay in the output, a 50 ohm non-inductive resistor input circuit instead of the more common and less stable tuned input circuit, air flow failure protection circuit, and a power monitor for forward and reflected output. The RF section contains 2 meters, one measuring grid, screen, and plate current and the second measuring forward and reflected power.
The power supply was designed with a choke input full wave bridge circuit to provide a very stable plate voltage. The power supply also contained an overload plate current protection circuit. In addition, the power supply is designed to shut down it the screen voltage failed.
Because of the heavy duty design of the power supply, the RF section could be converted to run 3 4cx350s or 3 4cx400s. These changes would only require a more robust filament transformer and a slight modification of the bias circuit.
My only criticism of the power supply design was the use of dropping resistors of the plate voltage (2000VDC) to provide screen voltage to a string of 3 voltage regulator tubes (OC3s). Given the quality of the amplifier, I would prefer to have a separate winding on a transformer (plate or filament/bias) to provide the screen voltage. With regard to the RF section, neither of the meters measures plate voltage, which would have been useful to monitor. Finally, the air cooling was insufficient and often resulted in the plastic spacers in the plate tank coil to soften and deform. I added a large muffin fan on the side of the amplifier to exhaust the heat buildup. With the additional fan, the amplifier runs cold even at heavy duty cycles.
In conclusion, the Delcon T210 is a real classic and if you can find one, grab it.

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