As long as Daniel scooped up ALL my tubes, which he said he did, i should have all of those. Even som ebrand new EL95.
dave
I wouldn't fuss over it, such a few volts.....
Tubes are forgiving creatures.
I've restored dozens of old german consoles for customers, and decades later, I hear they're still playing beautiful music.
Tubes are mechanically fragile and electrically tough. SS is mechanically tough and electrically fragile.
If a critical negative rail (like a bias supply) was being rectified by selenium, compensating for the forward drop difference would matter. That's not the case here and within 10% of nominal is more than good enough.
I stared a git repo to keep track of my resources in case anyone wants them: Grundig_KS580_Restoration_Resources/README.md at master * ricardo-re-azevedo/Grundig_KS580_Restoration_Resources * GitHub
Before ordering anything I checked the main transformer but was getting weird values so I pulled it from the amp and bench tested and also plotted out the voltage selector wiring as a reference: Grundig_KS580_Restoration_Resources/internal_connections.JPG at master * ricardo-re-azevedo/Grundig_KS580_Restoration_Resources * GitHub
Here are my secondary voltages and DC resistance values at 120V:
Pink leads = 280V, 44.8Ohm (main voltage rail)
Green leads = 7.4V, .8Ohm (heaters)
Yellow leads = 12.5V, 44.8Ohm (Connects to screen grid? in circuit should read -10V)
Brown leads = 7.4V, .8Ohm (heaters for the associated radio. Not sure why they are here.)
Primary resistances:
Black-Red: 6.8Ohm
Brown-Grey: 7.8Ohm
Grey-White: 1.7Ohm
Continuity all ok. Unless anyone thinks otherwise the transformer looks ok. I suspect the issue is a failed rectifier, which will be replaced anyway. The 280V rail is already lower than recommended by ~5-10V so I don't think I will need a resistor to drop the voltage.
on to ordering.
Before ordering anything I checked the main transformer but was getting weird values so I pulled it from the amp and bench tested and also plotted out the voltage selector wiring as a reference: Grundig_KS580_Restoration_Resources/internal_connections.JPG at master * ricardo-re-azevedo/Grundig_KS580_Restoration_Resources * GitHub
Here are my secondary voltages and DC resistance values at 120V:
Pink leads = 280V, 44.8Ohm (main voltage rail)
Green leads = 7.4V, .8Ohm (heaters)
Yellow leads = 12.5V, 44.8Ohm (Connects to screen grid? in circuit should read -10V)
Brown leads = 7.4V, .8Ohm (heaters for the associated radio. Not sure why they are here.)
Primary resistances:
Black-Red: 6.8Ohm
Brown-Grey: 7.8Ohm
Grey-White: 1.7Ohm
Continuity all ok. Unless anyone thinks otherwise the transformer looks ok. I suspect the issue is a failed rectifier, which will be replaced anyway. The 280V rail is already lower than recommended by ~5-10V so I don't think I will need a resistor to drop the voltage.
on to ordering.
grundig used to name the unit:"klangtruhe". freely translated as "soundcabinet".
I learned this naming from a close friend of mine who has been director at grundig before they were purchased by philips. I sent him the picture..
I learned this naming from a close friend of mine who has been director at grundig before they were purchased by philips. I sent him the picture..
ah, cool. I wish I understood some German going into this. Any info from your buddy would be great. It would be nice to compile all the info on these old Grundigs.
well, I sent him yr photo, and he said that he did not recognize it as a true german grundig. it was cobbled together with philips parts as much as his memory served. he is 80 now.. I did repair once his golden grundig tube amp signature series.
Interesting. Was this in the early 60s? I haven't found any Philips branded components on the electronics or any similar Philips designs from that period.