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Old 19th Mar 2020, 7:20 am   #166
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Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 3,938
Default Re: Kolster-Brandes MR10

I can confirm the Trader sheet and the KB service manuals (both examples) all agree on the values of the tone correction and tone control capacitors.
The 0.001 capacitor you had in the radio would appear to have been a mistake at the factory or changed at a later date.
Capacitors pass higher frequencies easier than low frequencies. So C39, on the trader schematic, being in series with the signal, will have a profound effect on the bass, the .001uf value will filter out (resist) far more bass than the designed .02uf .
The tone control cap C43, in effect in parallel with the signal, will have the opposite effect to C39 in as much as it will filter out the treble as the control is turned clockwise.
A more scientific explanation could be given but the above is my simplistic view of the function of those components.
C44 performs a function to help prevent any unwanted high frequencies or oscillation from occurring in the output valve getting to the speaker.
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