saba: W II (W2); Meersburg

Hello,

I am very happy to be the new owner of a Meersburg WII. However, there is a an "extra" transfomer on the input grid side of the EL34 output tube whose function I cannot understand. I have checked a number of other Saba schematics and this transformer does not appear in a similar place. Could someone who knows this radio please explain its purpose?

Cheers,

Mark

PS, I have checked a little more. Lindau WII has a similar arrangement. I also have studied the circuit a little more and it seems that the "extra" transfomer has something to do with the tone control presets. It also seems that the transformer works in some kind of feedback arrangement as well as providing a plate load for the EABC80.

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Hi, Mark,

Your Ideas are in the right Direction. This Radio has a 5 Position Tone Control Preset, as shown on the Operating Quick Chart. "Klanbild"

Position 1: Linear
2: Speaking
3: Musik and Speaking
4: Musik normal
5: Musik with Bass Boost

There is a Table showing which contact is closed at which Tone Control Position on the circuit Diagram.

To be able to have the required Bass Boost Function, and avoiding overloading the Output Stage in the Sub Bass below 16Hz Saba uses a Transformer with Cap parrallel to the primary coil.

 Some Month ago i had a SABA Freiburg W2 for Alignment, and this Radio also has a real Bass Boost " Always there, but never too much to overload Output Stage or Speaker"

Hope this helps,

Best Regards,

Henning

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Hi Henning,

Thank you for your explanation. I see well "the transformer with cap parrallel to the primary coil". You are referring to the coil on the right side of the output EL34 tube, I believe. My question refers to the transformer on the left side of the output tube. The anode of the EABC80 feeds to the grid of the EL34 via the secondary of this "interstage" transformer. The anode of the EL34 feeds back to its primary. I see this is part of the tone control. This scheme seems to have been dropped after the WII series.

Sincerely,

Mark

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Hi Marc,

 

did you really understand what Henning meant? Please post your question from the model. If you don't understands what we mean do not hesitate  and ask.

 

Kind regards

Olaf

 

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Hi Olaf,

Yes I did. But, as I understand it, he answered a different question. On the schematic there is a separate transformer that is independent of the output transformer that is part of the tone control preset circuit. My question is what is the function of the transformer in the tone control circuit?

Regards,

Mark

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Hello Mark,

Henning and Olaf are explaining that several of the Saba models in the WII series (I have a Schwarzwald WII and also the Meersburg WII) have what appears to be the small transformer arrangement in a tone control that is coupled with 5 detents to permit various presets.

Typically the left hand outer knob (the larger one) is rotated through the various positions and the schematics show the different presets as a, b, c, d, and e for the 5 different presets.

The different models use slightly different displays on the right side of the dial glass - Schwarzwald uses a small circular display with a variable sector. Tone control knob at full left is essentially full bass - middle position is equal blend of bass and treble (and the sector is half open) - finally with knob full right you have the high frequencies emphasized - the display sector is wide open.

The Meersburg has a slightly different "arrangement" with the 5-position detents varying the display of the bars in your TIEF MITTEL and HOCH windows as Herr Oelkers has described above.

However, not all of the models have the "added" circuitry to which I believe you are referring. The Meersburg has a BREIT presskey on the panel(meaning "breadth or width" as in variable bandwidth) to activate the circuitry when operating in the KW (shortwave band). Now, both tuning knobs on the right hand side are used - the outer large knob for the coarse tuning, and then the smaller knob performs the fine tuning (especially when there are several strong stations transmitting and may be only 5kHz apart). You can see both of the abstimmzeigers (tuning pointers) move - one on the KW band, and the smaller one on the left hand portion below identified as KW-Lupe. Don't be surprised to see the FM pointer move in synchronization with the KW-Lupe pointer.

So, you have the explanation for the "return circuit" to the EABC80!!

Respectfully,
Robert

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Hello Robert,

Thanks a lot for your clarification.

Sincerly,

Mark

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