two bridges on one secondary

[jpfastre]

I saw a schematic diagram of a Power Supply with two bridges on one secondary.
My question is:

Has this circuit any advantage? (better separation?)

Sorry for the ugly schematic diagram, In don't have a CAD program.

I searched in the forums and I hope I'm in the right Forum.
PLease correct if necessary.

 

[peranders]

I'll guess the problem with this is no real good ground for two channels, UNLESS you have _very_ lowohmish connections.

 

[Jan Dupont]

It provides a better channel separation between left and right channel, as each channels power bank caps are separated

 

[pixpop]

This is exactly how I built my gainclone power supply. I did it this way, because I bought PCBs for dual transformers, but then decided to use a single transformer. It works fine, but I don't have anything to compare it to (Haven't built another gainclone yet).

 

[Jan Dupont]

Channel separation can be difficult to dertermine by ear, unless it's catastrofic bad

 

[AndrewT]

Hi,
absolutely perfect.

Use the common 0volt point as your audio ground. Do not connect audio ground to safety earth. Instead use a disconnecting network between audio ground and safety earth.

The result, as already stated, is improved isolation (lack of crosstalk) between channels and near monoblock performance from each of the amplifiers.

Arranging amps and power supplies and cooling around the central audio ground will be your biggest challenge. Try to keep all the connections short, somehow.

 

[jpfastre]

I built it and it works fine.
I thank all the people for their help.

Use the common 0volt point as your audio ground. Do not connect audio ground to safety earth. Instead use a disconnecting network between audio ground and safety earth.

Do you have an example schematic diagram for this?
I know why but I don't know how to do it.

JP

 

[AMV8]

Hi

On power amps I normally do not connect the audio zero point to earth. In effect I leave it floating. However I do earth the case to mains earth usually via a thermister.

Don

 

[AndrewT]

Hi Amv,
if your case is separate from the audio ground, then you don't need a thermistor between cable earth and chassis.
You should connect the cable earth wire direct to chassis for maximum safety and due to floating ground this will have NO impact on sound quality.


HOWEVER,

if you lose a live connection that touches some part of the audio system then potentially you are making the internals live. If one component shorts this live voltage to audio ground then the speaker return terminal and the RCA ground terminal could both become live. Because you have NOT connected the audio ground to chassis the internals remain live, the amp apparently has gone dead but the terminals could be live and worse the fuse will not blow.

Now think what will any unknowing user do when the amp goes dead?
They get out their seat and go and investigate, maybe pulling and tugging at various connections etc.

One dead user. It could be your daughter!!!!!!!

You must connect the audio ground in some safe way to safety earth to ensure the fuse blows if the mains side ever goes wrong. This then ensures that the internals are live for the minimum amount of time.

Go and redesign the safety side of your equipment, NOW.

 

[Nordic]

Easy network...

4 components all in parallel

2 large diodes (about 8A and enough voltge rateing for your mains) wich should be placed to have oposite polarities from each other, in parallel with a 1W 10ohm resistor, and a mains voltage rated 0.1uf cap.

so 4legs go together on each side... leaving you with an in and out which you place in series with the groundline.. maybe just connect one end to ground on your IEC connector and the other goes with a wire to your circuit's ground.

 

[AMV8]

Andrew

I am surprised that you find my method unusual. I believe that others also insulate audio star ground from the frame.

Don