Hello diyaudio !
I recently bought a Thorens td 145 totally mint and i was able to do some modifications to improve hum :
I did the following :
- Added a separate ground(removed the ground from right channel).
- Replacing the RCA cables with mogami 2791 cable(big improvement !)
However, there’s still some very light hum(50hz) + high frequency whining(7000hz) in the signal(analyser picture attached) when the motor is running, it seems i still have some ground issues as :
-When i touch the base of the protective plastic cover, the hum is gone and motor noise almost gone .(red arrow)
-I did some tests with the protective box removed, and when i move the small solder board close to the big cap next to the plastic cover, the noise is increased.(orange box in the picture)
It seems i still have some ground issues but i can’t find the way to fix it :
-Could it be related to this cap(orange) ?
-Do i need a better isolation in the protective box ? I did not find any informations about this protective box and how to enhance it.
The picture of the thorens is not mine, it's just here for reference.
Thanks !
I recently bought a Thorens td 145 totally mint and i was able to do some modifications to improve hum :
I did the following :
- Added a separate ground(removed the ground from right channel).
- Replacing the RCA cables with mogami 2791 cable(big improvement !)
However, there’s still some very light hum(50hz) + high frequency whining(7000hz) in the signal(analyser picture attached) when the motor is running, it seems i still have some ground issues as :
-When i touch the base of the protective plastic cover, the hum is gone and motor noise almost gone .(red arrow)
-I did some tests with the protective box removed, and when i move the small solder board close to the big cap next to the plastic cover, the noise is increased.(orange box in the picture)
It seems i still have some ground issues but i can’t find the way to fix it :
-Could it be related to this cap(orange) ?
-Do i need a better isolation in the protective box ? I did not find any informations about this protective box and how to enhance it.
The picture of the thorens is not mine, it's just here for reference.
Thanks !
