F5X -- the EUVL Approach - The Build Thread

[lhquam]

Originally Posted by AndrewT

Not allowed.

All mains powered equipment should have all exposed conductive parts connected to chassis.
The Chassis must be permanently connected to the Protective Earth. This last connection must be low impedance (short thick wire) to ensure the chassis voltage cannot reach lethal voltage during a mains fault condition. That main's fault current can approach and even exceed kA.

The F5X power supply schematic shows power-line ground (Protective Earth) connected to the chassis.

My question was about the star grounds associated with the 15 volt power supplies and amplifier boards. These appear to connect only to the input connector shield, which if unconnected would allow the amplifiers to float. Maybe that is ok. An alternative might be to connect the star grounds to chassis via back-to-back diodes.

[AndrewT]

Originally Posted by AndrewT

.....All mains powered equipment should have all exposed conductive parts connected to chassis............

Originally Posted by lhquam

...........My question was about the star grounds ................

I answered your question.

[EUVL]

I need to be careful what I post here.

The chassis should be earthed. So should be the shield in the Tx. As Andrew said.

For my own use, I do float the star ground of both channels.
In my own audio chain, the only place where the left and right channel Gnd's are connected is at the player.
The rest of the chain is all floating.
But I do use back-to-back diodes + 1R resistor + cap (see Fig. 4 of the following link) to tie both star grounds to the chassis.

Earthing (Grounding) Your Hi-Fi - Tricks and Techniques


Patrick

[AndrewT]

No need to be careful.
If you recommend something potentially dangerous, I'm sure someone will recognise it and shout to the heavens how wrong that is.

But, from your description it sounds like you have incorporated a Disconnecting Network into your Safety Earth connection.

I tested a version of the DN and reported the results some years ago.

[lhquam]

Originally Posted by EUVL

I need to be careful what I post here.

The chassis should be earthed. So should be the shield in the Tx. As Andrew said.

For my own use, I do float the star ground of both channels.
In my own audio chain, the only place where the left and right channel Gnd's are connected is at the player.
The rest of the chain is all floating.
But I do use back-to-back diodes + 1R resistor + cap (see Fig. 4 of the following link) to tie both star grounds to the chassis.

Earthing (Grounding) Your Hi-Fi - Tricks and Techniques


Patrick

Thanks Patrick. That was the answer I was looking for. It is similar to Nelson's grounding.

Am I correct to assume that the "back-to-back diodes + 1R resistor + cap" is done separately for each channel?

[Nikon1975]

Does anybody need 16 22000uF 35V Panasonic HA caps :-( ?

D.

[EUVL]

> Am I correct to assume that the "back-to-back diodes + 1R resistor + cap" is done separately for each channel?

Yes.


Patrick

[EUVL]

Davide,

I presume you bought the 35mm diameter caps because if our mistake.
We'll find a special solution for you (and anyone else in the same situation) so that you can still use them.
You may have to solder the wires instead of terminal blocks.
But that would be a minor imperfection.

When I am ready I shall post the solution here.
I hope some time next week.


Patrick

[Nikon1975]

If the hight would fit, the absence of the terminal block it's not a big issue.

D.

[EUVL]

The case will allow 50mm height.
I do not think it is an issue.


Patrick