Grundig v5000 buzzing sound from headphones help

You figured it out: Unlike the speaker outputs, both head phone outputs do not employ relays. Hence the "plop".

Nevertheless, all outputs come from the power amplifer stage.
The head phone outputs just add a few resistors to limit the output power to some extent (not really much).
The hum you notice is most likely related to a much higher acoustical sensitivity of the head phone vs. "normal" speakers.
High-impedance head phones are prone to that issue in this particular environment.
You may add additional resistors for furher attenuation of the head phone outlets. Since there are two of them, you may want to change just one of them, keeping the other original.

Elkos: If you already removed them, never use them again! Since you did find several dead ones, the remaining ones are likey to fail sometime sooner than later. There is just no miracle about Grundig or any other manufacturer of that time past, they all were "cooking with water".

First off all thank you for your reply! My headphones are old vintage ones. I meassured them and they’re 32ohm is that ok? Btw i changed all elkos on nf modul but the ones i remowed were all ok! And I now feel stupid because all were good and brand name nichicon etc. it was very strange that one coupling elko on potenciometer was 10uf insted 22uf is that normal? It was factory seting and it was orange like others no one remowed nothing i was the first who opened this amp. Can you give me some tip how to unsolder components on this double sided laminated board? One more thing, I found that one big Roe elko had missing one rubber cap but I found it and put it back. Gently remowed all and gass exited put all back. Then unsoldered them for measurement. All have 12000uf esr abou 0,05ohm vloss 0,8-1%. Should i change them. Some guy told me that they are top quality. Is it normal that one chanel has at output 60mv and other 55mv?

zoso-yu (Beitrag #3) schrieb:

Then unsoldered them for measurement. All have 12000uf esr abou 0,05ohm vloss 0,8-1%. Should i change them. Some guy told me that they are top quality. Is it normal that one chanel has at output 60mv and other 55mv?

Maybe I'm wrong, but Nichicons would be fairly unusal back then. I suppose these Caps have been replaced earlier by someone else. This might explain the wrong value here and there. However, sometimes factories screw up as well. The service manual should tell you. In case you don't have it, the complete manual is available at "hifiengine.com".

De-soldering on double sided PCB requires fairly good tools:
1) A solder iron with at least 50W (better 80W), good/fast regulationand enough "thermal mass" to handle larger areas.
2) Either good and fresh desoldering braid, or a decent vacuum de-soldering station (again, the good ones are expensive).
The process should start by adding flux, or alternatively fresh solder wire to the spot. Old solder joints often show fairly high melting points, the additive or new solder will lower that. Try to remove as much of the old solder as possible prior re-installation of new components

Forget that crappy Roe Elko you put back together after "finding the rubber plug" ! Once apart it is absolutely dead.
Also, do NOT trust these cheapo-instruments from China, they are funny toys. Fairly often they report just nonsense, particulary on higher C-values (as well at the low end). If your device tells anything about an ESR of 0.05 Ohm, better start laughing!
Likewise, even better much Elkos will have much higher losses (above 5%, some larger caps 10% or more) than what you measured here.
Values at this low level would also require some pretty expensive measurement device to be anywhere reasonably true.

Dont't worry, 55mV, 60mV, even 100mV offset appear actually quite good for this old design.

Sorry it was no nichicon, my mistake it was nippon chemi-con :).
So buzzing via hedphones is ok. Should i close the lid and finish with shining the exterior :).
One more thing renewed the thermal paste on t501. He gets quite hot, the heat sink is hot. The voltages on measuring points Sk and Sl are 58v and 35v. Is that ok?

zoso-yu (Beitrag #5) schrieb:

Should i close the lid and finish with shining the exterior :).

I'd say yes.

The voltages on measuring points Sk and Sl are 58v and 35v. Is that ok?

Where the heck are these?

58V @Sk and 35V @ SL are perfectly ok!

Schematic says Sk --> 54V; SL --> 35V

Regards
Reinhard

Ok thank you. Is it normal to have 35v againtst chasis as - and two netz elkos as +? And one more thing I noticed only via headphones that 40hz tone control has strange sound when turning it fast like its dirty but I know it is not. I also had that problem with 300hz and 2500hz tone controle wich I solved before (one elko was 10uf instead 22uf). In schematic I see that elkos for 40hz are tantal. Should I excgange them. Can i snap them from the top and then solder new elko from top, because I’m afraid to destroy the board. Previous owner sprayed potis with wd40 It was a mess on the board had to clean it with alcochol.

Can you please describe more precisely, what you mean by "35v against chassis as - and two netz elkos as +"?

The power stage rail voltages are +39V/-39V for each channel, symmetrical against chassis. Two of the large elkos are with "+" towards chassis and with "-" towards power amp. For the other two large elkos its the other way around.

In more than one case, I had to replace the 22µ elkos of the tone control because they were dry or leaking. Usually no need to replace the tantals unless you got crackle/hum or sporadic popping noise. In the latter case the tantals schould be replaced, including the 1µ tantals C637/638. You can use elkos instead without loss in sound quality. I always go for 50V/low-esr types here.

To avoid destroying the board use good quality de-soldering braid, work fast, not too much heat, but enough to desolder in about 5-10 seconds. Sometimes even then a copper "eye" comes off. New parts can be soldered back nevertheless, if small diameter (0,3 mm) solder wire is used, liquid solder creeps along the solder pin of the part into the hole towards the other side of the board and makes the contact on the parts-side of the board correctly.

WD40 is not good! Kontakt 61, the blue, works well. Never ever use Kontakt 60 (the red)! If Kontakt 60 (red) was used nevertheless, it must be washed out with isopropanol thoroughly afterwards. Otherwise strong corrosion will appear after a few years.

Regards,
Reinhard

Reinhard, thank you very much for your interest, and help!

I was stupid, the metal of net capacitor ROE is negativ pole so it is ok to have 39v when I put negative probe on elko and positiv againts chassis on one elko per chanel because they are coupuled :). The thing is i didnt know that the metal housing of the elko is negativ pole :). I thaught that elko was defective. So I’ve replaced them with elna 56v 10000uf made in thailand. Hope that i didnt destroyed the sound? Are these elkos beter than this big ROE cans? Should I put them back?
Another thing the hum witch is coming from the headphones as I’ve said it’s only heard via phones speakers are dead quiet.
I accidently moved the flat cable that conects the headphone/switch board to the speaker output relay board and the buzz was quiter. I figured out that the buzz is coming from the transformer because the cable was fixed via zip tie to the transformer and it was picking some interferences probably it’s just my guess? I moved the cable a side and the buzz is more quiter but is still there. Am I right about this or should I be more agressive and change all elkos in preamp or some component that is producing this buzz or is transformer interferences?

There is no effect to the sound when replacing the big buffer elkos by ones with similar capacity. From that perspective it's not necessary to change them back.

If the speakers don't produce hum, only the headphones you won't have an improvement when changing elkos. Often, the headphone jacks pick up some hum. it depends also on the sensitivity (impedance) of your headphones. Lower impedance is better here. Influence from transformer and how the cable is positioned is possible.

regards
Reinhard

Ok I closed the amp, the hum on the headphones is now gone. I moved the cable away from the transformer and the hum gone.
And now a little help with wires :). Ok I’m not new to hi-fi have lot of equipment but a little help with the connections.
I plan to connect t5000 tuner cf 5500 tape deck philips n7300 reel to reel, cd player computer and turntable with mm cartridge.
Tuner goes to tuner via din, ok thats easy, and how to connect cf 5500 via monitor or tape 1din? I want listen to what I’m recording thats the point with 3 head deck. How to cennect philips n7300 reel to reel to listen to recordings?

That's all described in detail in the user manual. In several languages.



regards
Reinhard

Reinhard,
Thank you very much for all your help the 5000 system works excellent. Everythnig is hooked up. Enjoying the music !
Where can i find service manual in english? I need for t5000 and cf5500 also?

Gratulation!

The german SM is here and here. Maybe that helps more than no SM.

Sorry I ment to say, where can I find user manual in english? I’ve downloaded the sm for all three components.