Tube Preamp Stage Question

[weston530]

Hi! I am a wicked amateur and I have a newbie question for something that is confusing me.

Currently replacing some blown resistors and old capacitors in and old jukebox and reviewing the schematic.

Between the phono preamp and EQ/balance controls and tube preamplifier, I am curious why the audio signal wouldn't just follow this red path I drew to ground, and why any signal would flow on the green path, which is must to function?

I am sure the answer is simple and obvious but my tiny brain just thinks shouldn't all the voltage just go to ground never to be seen at the inputs of the tubes?

Please help me understand?

Thank you,
Dan

 

[MarcelvdG]

I guess the shields are supposed to be grounded, but someone made a mistake drawing it. It doesn't make sense to ground the signal lines for the reason you gave, but it also doesn't make sense to leave the shields of the shielded cables floating.

 

[weston530]

Ah ok.. that make sense. If thats the case I feel slightly less dumb. Thanks MarcelvdG!

 

[thisusername]

I guess the shields are supposed to be grounded, but someone made a mistake drawing it. It doesn't make sense to ground the signal lines for the reason you gave, but it also doesn't make sense to leave the shields of the shielded cables floating.

Older schematic conventions only showed where the shield is connected to ground.

 

[weston530]

Now knowing, seeing this part it makes more sense what is going on. Screwed up my logic at first though.