Linear Amplifier 2 x QB5/1750Linear Amplifier 2 x QB5/1750

Front side of amplifier and power supply, all in one box.

Rear side. Tube blowers, automatic fuses for 220V, antenna connectors and fuses.

Linear Amplifier 2 x QB5/1750Linear Amplifier 2 x QB5/1750

Two coils, bigger one for lower bands and small one for 14, 21 and 28 MHz.

Two Siemens paper in oil capacitors, 32 MFD/3750 V serial connection, transformer for heating 20V/10A. HV transformer ( 1900, 2250, 2500V). High voltage is doubled, maximum is 5500V stand by and 5000V key down. Plate current is about 1A key down.

Bleeder resistors 100K/100W

HV, plate current, G1 current and output meters.

Modified plate coolers, of 2C39BA tube.

Under the chassis. Strong zener diode with 2N3055 transistor on black cooler.

RF choke and Giant sockets for tubes. One of the socket is home made of ash tray!!!

Jovan Djurkov 4N7AE on top of the YU7BCD radio club Mihajlo Pupin Pancevo building!


This Post Has 2 Comments

  1. Johannes

    Hello thanks for de nice foto,s
    i like schematic of this linear.
    when you need transmitter parts i havemuch
    greetings johan

    1. Freddy

      Great design of the qb5/1750
      Is it possible to send me the building instructions
      I woud appreciatie this a lot
      Greetings 73,s ON7FL

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