Powersupply layout

[Skorpio]

I have build a powersupply for my amp, and included a Capacitor Multiplyer.

The Cans on all electrolytes are grounded...do that give more noise than if a try to seperate them? I don't mean grounded by wire (they are that too), but all cans are mounted on the chassis with nuts at thereby connected via the chassis.

Can noise from the first cap (with the ripple current) inject into the others and reach the output?

[Jan Dupont]

Hi,
Don't use the chassis as Ground!!!
Better make a "star wiring" to all Ground terminals on PCB's and components.

In a tradiotional chassis you can newer be sure that the electrical connection between the separate parts of the chassis are zero Ohms. And if you have yet another ground connection to the chassis, there is a great risk to create a humming "Ground loop".

[Skorpio]

I have made a star-ground connection on the caps, but since the housings ALSO are connected to the - termainals, all the caps have direct connection via the chassis....(this is not ground).

[Jan Dupont]

If the caps are the type with a thread in the end for mounting, I would use some kind of plastic insulation bushes.
I'm not an expert on caps, however I have plenty of bad experience with other components causing "hum loops".

[Nelson Pass]

Since it is impossible to make a true, perfect "Star" ground, I
recommend what I call a "Hierarchical" ground. The idea is to
isolate the "dirty" ground connections from the "clean" ground
connections by stacking them so that high noise currents don't
flow through the clean grounds.

Imagine a grounding bolt. The first thing to go on it is a lug which
attaches to the transformer ground, or whatever passes for it.
This is the dirtiest ground in the system. Next lug is the first set
of power supply caps (often I simply pass the bolt through
whatever plate is connecting the cap grounds).

If you are using a pi filter, the next lug goes to the grounds of
the second set of supply caps. Next is the speaker terminals
and any miscellaneous power grounds, decoupled capacitors,
etc. Then the chassis ground, if you are connecting it directly.
Then the input and feedback grounds at the top.

If possible, use completely separate transformers (or
secondary windings) for each channel, which isolates the two
channel's grounds and prevents ground loops in the system
flowing through the input grounds.

Always ground the chassis to earth. I then recommend attaching
the channel grounds to the chassis via Thermistors or diode
bridges. This gives some ground loop prevention while still
keeping the potential for shock very low. The power supplies in
the Zen Variations are good examples of this.

[lucpes]

Here's a layout I'm planning for a class AB amp, so I don't have CL or CR filters in, just plain vanilla trafo-bridge-caps layout...

Any troubles with this layout? I have it wired the way shown here on a table and so far no problems with hum/noise & stuff like this. I'd leave the case 'floating' (not connected and only connect the toroid's shield winding to the AC power ground)

X marks the spot for the 'star' grounding. Other than keeping ground returns for rails same lenght I really can't think of other things that may hinder my amp.

Comments?

edit: it's really line 'hot' and rail 'ground', not balanced using 2 wire/shield mic cable, shield connected to RCA ground only[/SIZE]