radiomuseum.org
Please click your language flag. Bitte Sprachflagge klicken.
 

grundig: 5040W/3D (5040 W/3 D);

Moderators:
Martin Renz Ernst Erb Vincent de Franco Martin Bösch Bernhard Nagel Otmar Jung Heribert Jung Eilert Menke 
 
Please click the blue info button to read more about this page.
Forum » Radios and other type of sets (Physics) etc. » MODELS DISPLAYED » grundig: 5040W/3D (5040 W/3 D);
           
Ross Hochstrasser
Ross Hochstrasser
 
USA  Articles: 24
Schem.: 0
Pict.: 19
24.Apr.09 05:04

Count of Thanks: 10
Reply  |  You aren't logged in. (Guest)   1

What is the reason that the cathode resistor has no bypass capacitor? I have experimented with my 5040W/3D by adding a 100 Uf 50 volt capacitor and there is a noticable difference in audio gain and bass response, however, I realize that Grundig didn't typically leave anything out. What have I compromised by adding the capacitor, if anything??

Emilio Ciardiello
Emilio Ciardiello
Editor
I  Articles: 533
Schem.: 165
Pict.: 790
24.Apr.09 14:17

Count of Thanks: 10
Reply  |  You aren't logged in. (Guest)   2

Dear Ross,

The cathode resistor gives a DC drop to properly bias the grid of the output tube. The cathode capacitor, when used, acts as a low-impedance path, something like a short-circuit, for audio frequencies. Removing the capacitor, Grundig added some AC feedback, to improve the fidelity of the output stage. Gain was more or less decreased, but they had power enough from the EL12.
 

Regards, Emilio

Ross Hochstrasser
Ross Hochstrasser
 
USA  Articles: 24
Schem.: 0
Pict.: 19
25.Apr.09 03:30

Count of Thanks: 3
Reply  |  You aren't logged in. (Guest)   3

Thank you, Emilio, for the clarification. I added the capacitor over a week ago, and am realizing that although there is an increase in gain, there is also more distortion. I also noticed that the action of the treble control is  odd and the loudness contour feature of the volume control is abnormal as well. I'm going to remove this capacitor now that I have realized the  effects it caused. Thanks again, Ross

James MacWilliams
 
 
GB  Articles: 56
Schem.: 0
Pict.: 8
28.Apr.09 22:14

Count of Thanks: 9
Reply  |  You aren't logged in. (Guest)   4

Ross,

Do you have a user or owner's manual for this radio?  I just purchased a 5040 (German model) that I plan to refurbish, but it would be nice to know how it was suppose to work.  I have schematics and technical drawings, but not an owner's manual.  Any clue where to find or purchase one would be helpful.  Regards,

Jim

Ross Hochstrasser
Ross Hochstrasser
 
USA  Articles: 24
Schem.: 0
Pict.: 19
29.Apr.09 05:40

Count of Thanks: 9
Reply  |  You aren't logged in. (Guest)   5

Hi, I may have one, I'll check the 5040 file and see. I'll try to respond tomorrow. Thanks!! Ross

  
rmXorg