saba: Saba 580WK - controls?
? saba: Saba 580WK - controls?
Hallo, Friends! I have a question about my Saba 580WK (1938): I have no "manual", only the schaltbild. There seems to be two volume controls? Facing the radio, on the left, there is, I believe, the main volume control which is also the mains on-off control. On is engaged by pulling the control out; turn off by pushing the control in. On the right side is another control which seems to make two different tone controls. Pushed in, the tone appears deeper, more bass. Pulled out, more treble. Turning this control also changes the volume. This does not seem correct!
Would someone please give me a description of these two controls? I also have s Saba 455WK, and its controls do not work in this manner.
Many thanks for your help!!
Alexander (Sandy) Gerli AC1Y
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IF-filter
The right hand side control acts as a continuously adjustable intermediate frequency filter. One of the 3 coils is getting moved mechanicaly by something like a cardan shaft. It changes the bandwidth of the filter. The 455 WK and the 580WK use a similar circuitry. I think on all of these modells changed or lost the silver micas (220p) their capacity due to corroded silver coatings.
You find these caps inside the filter tube. Probably these caps detune your filter and cause the problems.
All of these caps should be replaced by new silver micas with 1% tolerance.
The right hand control acts as a bass cut filter when pushed, full bandwidth when pulled. You get a small bandwidth when turned counterclockwise. There is no influence on volume, when it is correctly adjusted.
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Saba 580WK IF Filter
Hallo, Martin! AHA! a variable IF Filter! Certainly, that explains it. My Saba 455WK operates as you describe - the capacitors are probably OK in that one! I have a number of silver-micas in my stock of parts, 220pF seems to be an ordinary value.
While I am doing that, I also will change the electrolytic filters as well. I have used 47uF/450V with very good results in other radios.
mfg!!
Alexander (Sandy) Gerli AC1Y
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