kolsterbr: FB10; Midget

Changes in the valve lineup of this Kolster Brandes radio (known as "The Toaster") were made during the production run. After serial number 110,000, the valves used were 6BE6, 6BJ6, 6AT6, 6BW6 and 6V4. Other valve substitutes during production have also been reported, and my own model contains a 6BE6, 6BA6, 6AT6, 6BW6 and 6X5GT.

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William,

did they also use B7G valves but with a 6V6GT at one stage?
Sure I remember seeing one.
I always compare these small sets with the Bush DAC90A,
and I'm sure none work as well - what do you think?

Regards,
                John Turrill.

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Yes, John, your memory serves you right. Reading through other forums, it appears that almost "anything goes" as far as this radio is concerned. There were lots of variations to the circuit on this model. It appears that the manufacturer tended to use what was available at the time. It is probable that there were still shortages of components around the early 50's, following WW2, so there are variations in valve types and components used. Sets have been reported with a mixture of octal and B8A and some have B8A and B7G. Others have all B8A or all octal...there are probably some that have octal and B7G. Some have chassis punched for octal but have conversion plates fitted in the original holes to take different size valves....the list goes on. The schematics should therefore only be used for guidance and as many as twelve chassis variations have been reported. Some of the earlier sets also used frame aerials as opposed to ferrite rods.

There is no doubt that the Bush DAC90 is a much better performer. It has a larger case and speaker, of course, and Bush did not seem to have the same problems as KB with regards to sourcing components around 1950.

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Hello,

I recently acquired and overhauled one of these KB FB10 midget radios and have seen a KB service data supplement sheet dated January 1954 covering sets with serial number 60,001 onwards. The circuit diagram which accompanied this update has a 6BW6 output valve rather than a 6V6GT. The frame aerial was also replaced by  a ferrite rod aerial and a minor change was made to correct modulation hum by removal of the 0.1uF capacitor across the mains input and introducing a 0.05uF capacitor between rectifier anode and chassis.

Other changes may well have been made from time to time, these sets do tend to vary a bit ! 

The FB10 was replaced by the FB10/2 model in June 1955, serial number 110,001 onwards with several more changes and that has a separate model page on RMOrg.

Regards .......... Howard

 

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