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Hello Woodstoock The tube EL11 was available in two variants: EL11 or EL11/375. Which variant is in your set in use? Which model of Sachsenwerk do you have?
The typical primary impedance of a transformer for EL11 is approx. 7 k ohms. The impedance for EL11/375 is approx. 9 k ohms
In both cases the secundary impedance of the transformer for the speaker is 4 ohms (not 5 ohms, but this difference is not so important).
Sorry, but I have no information about the field coil for the magnetic field of the speaker. You can replace in case of a defect field coil the electrodynamic speaker with a permanent dynamic type. But you have to substitute this coil with a resistor.
Mir gibt die von Woodstock genannte Anodenspannung von 150 Volt zu denken. Interessant wäre es zu wissen, wie hoch diese mit gezogener EL11 ist. Ich vermute Möglichkeiten der Ursache in der Gegenkopplung, einem defekten Koppelkondensator oder einem Katodenelko mit Kurzschluß.
Viele Grüße und ein schönes Wochenende wünscht Wolle
Already fixed the problem The type is a Sachsenwerk 401 WK Olympia (still searching for more parts, see other topic and foto's) The transformer was connected in the wrong way (by me) I was a bit confused by the speaker system as part of it plays a role as 'feld spuhle' for the pre-magnetisation,and this is in series with the speaker transformer.
The voltages are ok now 160 v Anode on the EL 11. I am not using AZ1 at the moment but a modern diode rectifier. Need original trafo first for the AZ1.
I now have replaced all tubes (exept AZ1) with NEW ones. The EL11 i now use is Tubular shape Telefunken, the original is Philips stepped-baloon shape. Optically the newer EL11 looks better as all other tubes are short metal series. The AZ1 is VALVO with grid-Anode plates.
Hello Woodstock, what is with the 160 volts on anode of the EL11? I think that is too low. The tube will 'see' approx. 200 to 250 volts. But 180 to 200 volts is in case of a pre-magnetisation coil ok. What is the difference voltage before and after the pre-magnetisation coil?
The anode quiescent current of this model 401 is 35 mA.
Ok, i was not sure what the voltage should be from the AZ1, as i do not have it in use now.
I Set the voltage from the rectifier to the input of the pre-magnetizing coil to 250V . At the output of this coil i measure 158V, so a 92V drop! Then trough the impedance transformer151V at the Anode of the EL11.
cathode elko is ok cathode resistor measures 143 ohms, thats ok for 150 resistor, i asume. Cathode current is 21 ma
Could it mean the pre-magnetizing coil is deffect? However, it does play pretty well and loud! When i do maximum volume it does distort some, but then i see ripples at the powersupply also, so that may be one reason.
Hello Woodstock, it is important to know the quiescent current trough the cathode of the EL11 . Without any AF signal a typical value is approx. 35 mA DC current. Please check this . ??? Regards Rainer
Ok i measured the cathode current, and this is 21 ma. at 156 v on the anode Powersuply set at 250 vdc i still can't find the official power voltage, so i will keep it at 250v for the time beeing. But i expect the voltage from the AZ1 to be more? Do You know? It depends on ther secondary of the mains transformer, and i do not have details on that trafo. However, the maximum dc voltage for the power elko's is 350V, so, maybe 300 volt is ok? When i measure with 250 volt. most of the voltages in the scheme are to low. But it does still work pretty good. (on the photo the orange and blue wires should be reversed)
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