nordmende: E330 Ch= 1/633; Tannhäuser-Stereo

I would like to install an FM stereo decoder to my model E330 Tannhäuser-Stereo Ch = 1/633. I would beg help me. whether a module can be adapted to this radio.
Thank you.
 Thank you. juan antonio sanchez.

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Dear Juan,

I assume that you intend to receive FM-stereo broadcast with your Tannhäuser E 330. Sorry, but I can give you only very general guidance because I do not know which equipment and knowledge are available.

1. Precondition for this purpose is a working FM stereo-decoder unit, e. g. from another radio.

2. Look at the wiring diagram (schematics). Below the ratio-detector with EAA 91 you will find the resistors R 134/ 22 kOhm and R 135/22 kOhm and the capacitors C 134/470 pF and C 135/1000 pF.

I think that you will have to remove at least C 135 (for de-emphasis) and possibly to decrease R 135 (try and error).

3. Connect the left pin of C 141/0,022µF with the FM-multiplex-input of the stereo-decoder. Then connect the L- and the R-output of the decoder via two capacitors of about 0,1 µF

a) with a stereo amplifier (AUX-input) or

b) with the corresponding input of the R 161 and R 171 potentiometers of your radio.

I wish you success !

Best regards

Rolf

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Dear Rolf. thanks for your response. I searched the internet some stereo decoder circuit to use. I found a kit "Stereo Decoder Bausatz Kemo B127".
you believe that this circuit can serve?.
thanks.
juan antonio.

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Dear Juan Antonio,

This is a good idea, try this device.

Maybe that C 141 is not present in your radio because of the reference „nur bei Truhen“. In any case, C 135 has to be disconnected. It serves as a low-pass filter together with R 135. It will be sufficient to unsolder its connection to R 135.The left wire from R 135 leads the “FM-NF” as noted in the schematics, and, after disconnection of C 135, in addition the high frequencies up to 53 kHz which are needed from your decoder for proper working.

A first evidence that the decoder works will be that its indicator-LED will be switched on.

Rolf

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Dear Rolf.
I have not responded until now because I was waiting for the decoder. As you commented I've removed the C135 and R135 reduced to 10k. Then I got to give me the signal decoder. Audio inputs take them via the keypad. Disconnect the mains just after the C141 (curiously is only 0.1 mf). The outlet of the decoder takes the pin 7 of ell80 (7 v). All grounding the chassis of the radio. The result is very satisfactory. The sound is excellent although perhaps shallow stereo. I am very grateful for your advice.
I hope to improve a little more depth of sound.
Juan.

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Hello all

Shallow stereo could be because when you push on UKW switch, left a righ inputs are crossed. See here at schema.

I have answer you this same question in talk forum (may be those are not the correct forum), so will repeat here my anwer. On it I suggest to use the TA Switch with UKW to select the stereo output of the decoder , and remains the UKW only to original Mono signal. This could solve the "shallow stereo" problem.

________Copy of my message on Talk board ___

Hi Juan

Just now there are a original valve Stereo decoder for this radio on sale on ebay. I can't see in schema how this decoder is conected on the radio May be somebody could help us about this. (there are a "filtersockel anschlüsse" - "filter socket connector" reflected in schema but i can't see where connect this??? )

I never done this on a valve radio, but I've done a lot in transistor radios. After examining the Schema, I could suggest you to start with these steps. You could build or buy a IC stereo decoder, and power it with a 9V battery on first. You only have to take audio signal before de-enfasis network, trought a 22nF 250V condenser. You probably must put a small poty of 100K here to adapt signal to the stereo decoder input to no saturate it. Decoder output could be connect to the TA input, so to receive in Stereo, you must push the TA button simultaeuos with UKW. There are a contact on TA  switch that you must cross too, because when you push on TA this disconnect last IF radio  (marked below on my schema ). As this is a "theorical mod" probably could need some mode mods althought.

 

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