I am considering an EI type power transformer with two electrostatic screens between primary and secondary. Similar to how this: VinylSavor: Power Transformers
"The first one,which is closer to the primary is directy connected to the core, which should have an electrical connection to the chassis and thus to mains earth. The second screen is meant to be connected to signal ground. This provides an even improved isolation from mains noise."
I plan to have one built to my specifications however I realized that I know very little about grounding. I am building the DCPP mono tube amp which originally used the Hammond 290FX power transformer (https://www.hammfg.com/files/parts/pdf/290FX.pdf) with the 0V being the ground connected to the PCB.
So if this new transformer has two grounds instead of the one that the Hammond 290FX has how do I ground this amplifier properly? Engineer's amp 50W monoblock
"The first one,which is closer to the primary is directy connected to the core, which should have an electrical connection to the chassis and thus to mains earth. The second screen is meant to be connected to signal ground. This provides an even improved isolation from mains noise."
I plan to have one built to my specifications however I realized that I know very little about grounding. I am building the DCPP mono tube amp which originally used the Hammond 290FX power transformer (https://www.hammfg.com/files/parts/pdf/290FX.pdf) with the 0V being the ground connected to the PCB.
So if this new transformer has two grounds instead of the one that the Hammond 290FX has how do I ground this amplifier properly? Engineer's amp 50W monoblock
If you did have two electrostatic screens, then there may be some advantage to connecting the primary side screen to protective earth mains input directly (ie. as an extra ring lug to the chassis bolt, or a new chassis bolt next to the protective earth bolt). Parasitic mains AC side currents then flow as directly as possible back to the mains, rather than through your chassis.
This doesn't mean all mains side noise goes via the electrostatic screen, as one 'face' of the mains winding is next to the core (if the transformer primary is layer wound), in which case the mains terminal associated with the inner core layer should be connected to the 'neutral' side of the mains input (ie. not the active terminal that has the mains ACV on it relative to protective earth).
The use of multiple electrostatic screens is often found in laboratory grade measurement equipment.
But it is worth appreciating that if you have a noisy home environment, and need to alleviate clicks and other audible noise, then identifying the culprit and doing something at the origin of the noise source is the better target.
This doesn't mean all mains side noise goes via the electrostatic screen, as one 'face' of the mains winding is next to the core (if the transformer primary is layer wound), in which case the mains terminal associated with the inner core layer should be connected to the 'neutral' side of the mains input (ie. not the active terminal that has the mains ACV on it relative to protective earth).
The use of multiple electrostatic screens is often found in laboratory grade measurement equipment.
But it is worth appreciating that if you have a noisy home environment, and need to alleviate clicks and other audible noise, then identifying the culprit and doing something at the origin of the noise source is the better target.
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