• Country
• Great Britain (UK)

• Manufacturer / Brand
• Kolster Brandes Ltd. (KB, K.B., ITT); Foots Cray; GB

• Year
• 1951 ??

• Category
• Broadcast Receiver - or past WW2 Tuner

• Radiomuseum.org ID
• 232526

Click on the schematic thumbnail to request the schematic as a free document.

• Number of Tubes
• 4

• Valves / Tubes
• 6BE6 6BA6 7C6 6G6G

• Number of Transistors

• Semiconductors
• 6SR7_Vibrator

• Main principle
• Superheterodyne (common); ZF/IF 422 kHz; 2 AF stage(s)

• Tuned circuits
• 6 AM circuit(s)

• Wave bands
• Broadcast plus more than 2 Short Wave bands.

• Power type and voltage
• Storage Battery for all (e.g. for car radios and amateur radios) / 6 Volt

• Loudspeaker
• Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 8 inch = 20.3 cm

• Material
• Wooden case

• from Radiomuseum.org
• Model: GR13T - Kolster Brandes Ltd. KB, K.B.,

• Shape
• Tablemodel, with any shape - general.

• Dimensions (WHD)
• 485 x 305 x 200 mm / 19.1 x 12 x 7.9 inch

• Notes

• Probably an export model as it's 6V DC only, no long wave and not listed in usual UK service sources.

  Features

  • Aerial/Earth sockets (no built in aerial).
  • PU/Gram sockets.
  • External speaker sockets with screw switch.
  • Plessey 6SR7 6V synchronous vibrator pack (not a metal 6SR7 tube/valve) so no HT rectifier required.
  • Power cord has 10 amp fuse on side of chassis.
  • Two  scale lamps/dial bulbs.

  8 Wavebands:

  • MW 185 ... 550 m
  • SW 35 ... 100 m (3 to 9.5 MHz)
  • 31m
  • 25m
  • 19m
  • 15m
  • 13m
  • 11m

  The OAK V5211 6V synchronous vibrator pack (Split Reed type) appears to be identical connections to the Plessey 6SR7 unit and has required specification (100Hz, 6V, 4A input max., isolated HT reed). The separate HT "synchronous rectifier" reed is connected to the +6V input filter rather than 0V. The "snubber" network across the secondary of the transformer is critical and is 10K Ohms in series with 10nF @ 1000V. A 1500V or 2000V rated part for replacement would be reasonable. But the actual capacitor and resistor values are related to the vibrator frequency and transformer 

  Total consumption is 2.3A @ 6V excluding two scale lamps / dial bulbs. The example model had 2 x 300mA bulbs but 150mA or less types (@ 7V rating) would seem reasonable.

  A small "shutter" is driven across tuning scale by wave change switch to indicate selected band.

  The RF/IF is similar to Kolster Brandes LR30 and the 7C6 6G6G Audio is similar to many 6V vibrator pack driven car radios, with addition of an active tone control that seems similar to some Kolster Brandes mains models (but not the LR30).

• Net weight (2.2 lb = 1 kg)
• 6.5 kg / 14 lb 5.1 oz (14.317 lb)

• Author
• Model page created by Michael Watterson. See "Data change" for further contributors.

• Other Models

• Here you find 415 models, 372 with images and 253 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Kolster Brandes Ltd. (KB, K.B., ITT); Foots Cray; GB