DAC humm: suspect grounding issue

[lga775]

Would like to ask is there any grounding issue in my circuit? Currently running 6n6p SRPP.

Your help is highly appreciated.
Thank you for your time and consideration.


Earth Ground
1. Connected to chassis
2. Transformer screening – analog
and digital
3. AC Tube heater

Chassis ground
1. Power supply caps
2. Signal ground

Signal ground
1. Digital ground to rca ground
2. Rca ground
3. Tube pin9 ground
4. Resistor cathode ground

Digital ground not earthed.

 

[Bill Fuss]

If you have signal ground connected to chassis and earth you have a perfect ground loop opportunity. Isolate the electronics from the chassis with a thermistor or diode bridge or something.

 

[Bill Fuss]

There is no image.

 

[lga775]

If you have signal ground connected to chassis and earth you have a perfect ground loop opportunity. Isolate the electronics from the chassis with a thermistor or diode bridge or something.

I did remove the earth from signal ground still the same.

 

[Bill Fuss]

Without a diagram it's very hard to help. You have many ground loops, according to your notes.