the additional cap will reduce ripple further still, its well worth while having it there.
Grounding rules dictate you should have a mains earth connection to the metal chassis of the equipment. the mains earth connection enters usually via an IEC mains socket. The amplifier or device should use a method of star grounding which just means that individual ground connections should go to one location and should not interfere with each other.
To visualize this think of currents in each branch making their way to ground, you soon get an appreciation of what star ground is trying to achieve. If you look at say a Quad 405 circuit board,an amplifier that has achieved over 90,000 units thats 180,000 circuit boards, has Quad satisfied a star grounding requirement? Well if we look at how the board is wired the power transistors and components needing ground with some current have the block of metal that connects to chassis as their grounding point, whereas the input has a wire connecting to the Input plug, now between the two is a 10 ohm resistor. so lets work out what Quad are doing- They have allowed the power ground access to chassis and the input and a few other less current hungry components are 10 ohms above, in the process Quad have satisfied that chassis ground will have access to ground slightly different to input ground, in the process making a slight ground lift a poor mans star ground that arises from mass production, in effect a recognition that ground for the input is just slightly different- all OK in the overall scheme of things. Moving on to the bridge rectifier and capacitors Quad allow these components access to the central point where the capacitors and transformer centre tap are which then has a wire to the chassis.
Now we can see that star earthing with slight caveats for the input ground lift has been satisfied. The current hungry components are allowed access to chassis via a track on the circuit board - the track is in effect a star ground, the PSU has a wire leading back to chassis, another star ground, and the input has a resistor which can be viewed as another star ground ( just- with a bit of imagination and that quad needed to sell their amplifier )
Hope this helps / Chris
In the case of your amp, At that location where ground returns meet usually the negative side of the power supply capacitor in single rail equipment is likely to be best this central star location. From that location extend a wire to chassis ground. The IEC plug ground safety ground should ideally return to that same point as the chassis ground connection. You have then satisfied grounding of chassis and components. Your grounds have ended up at one location the negative of the cap then connects to the chassis that then connects to safety mains earth.
Grounding rules dictate you should have a mains earth connection to the metal chassis of the equipment. the mains earth connection enters usually via an IEC mains socket. The amplifier or device should use a method of star grounding which just means that individual ground connections should go to one location and should not interfere with each other.
To visualize this think of currents in each branch making their way to ground, you soon get an appreciation of what star ground is trying to achieve. If you look at say a Quad 405 circuit board,an amplifier that has achieved over 90,000 units thats 180,000 circuit boards, has Quad satisfied a star grounding requirement? Well if we look at how the board is wired the power transistors and components needing ground with some current have the block of metal that connects to chassis as their grounding point, whereas the input has a wire connecting to the Input plug, now between the two is a 10 ohm resistor. so lets work out what Quad are doing- They have allowed the power ground access to chassis and the input and a few other less current hungry components are 10 ohms above, in the process Quad have satisfied that chassis ground will have access to ground slightly different to input ground, in the process making a slight ground lift a poor mans star ground that arises from mass production, in effect a recognition that ground for the input is just slightly different- all OK in the overall scheme of things. Moving on to the bridge rectifier and capacitors Quad allow these components access to the central point where the capacitors and transformer centre tap are which then has a wire to the chassis.
Now we can see that star earthing with slight caveats for the input ground lift has been satisfied. The current hungry components are allowed access to chassis via a track on the circuit board - the track is in effect a star ground, the PSU has a wire leading back to chassis, another star ground, and the input has a resistor which can be viewed as another star ground ( just- with a bit of imagination and that quad needed to sell their amplifier )
Hope this helps / Chris
In the case of your amp, At that location where ground returns meet usually the negative side of the power supply capacitor in single rail equipment is likely to be best this central star location. From that location extend a wire to chassis ground. The IEC plug ground safety ground should ideally return to that same point as the chassis ground connection. You have then satisfied grounding of chassis and components. Your grounds have ended up at one location the negative of the cap then connects to the chassis that then connects to safety mains earth.
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hm.... thats much of words, but currently i'm going to school, so i will read it after my class.
I have just brought the items, i can afford film cap, but no stock, haha !
I also brought the bridge, in case we need to use.
The IEC is the thick plastic tri-terminal thingy ? I already ground the main earth to my chassis, but not any further connection from the chassis.
About the yesterday noisy like radio, probably is ground loop ?
I have just brought the items, i can afford film cap, but no stock, haha !
I also brought the bridge, in case we need to use.
The IEC is the thick plastic tri-terminal thingy ? I already ground the main earth to my chassis, but not any further connection from the chassis.
About the yesterday noisy like radio, probably is ground loop ?
some photo's Here we have a Quad 405
The circuit board assembly has a star ground extending from a track on the circuit board to chassis ground. The input ground is lifted 10 ohms and takes (from the circuit board- slightly wrong, but allowable as this is a mass produced item ) its path is also to chassis
The PSU has three green wires one is the centre tap of the transformer that goes to the central ground point of the capacitors, that then connects to chassis ground. PSU Ground
The other two wires are from the speaker negative that connects to chassis ground.
The final photo is the Chassis then connecting to IEC mains ground.
The circuit board assembly has a star ground extending from a track on the circuit board to chassis ground. The input ground is lifted 10 ohms and takes (from the circuit board- slightly wrong, but allowable as this is a mass produced item ) its path is also to chassis
The PSU has three green wires one is the centre tap of the transformer that goes to the central ground point of the capacitors, that then connects to chassis ground. PSU Ground
The other two wires are from the speaker negative that connects to chassis ground.
The final photo is the Chassis then connecting to IEC mains ground.
Attachments
No wonder you are having problems !! 
i need to know more about the transformer you are using. As your power supply is in another case, my advice is to have its secondary AC extending to the amplifier case. AC unlike DC will travel distance without problems.
If its a single secondary winding no problems, if you have two secondary windings their centre tap is probably best joining close to the bridge rectifier in the amplifier case.
So view the power supply as a source of secondary AC only.
At the amplifier case receive the AC straight into a fuse on its active then a switch then into a bridge rectifier and capacitors. Have all of your grounds return to the amplifier case chassis. From that chassis have a earth connection to mains earth. You could do this between the PSU and Amp chassis with a mains type lead -3 conductors in this case 2 wires are used for secondary AC and the other is the earth.
Cheers / Chris
i need to know more about the transformer you are using. As your power supply is in another case, my advice is to have its secondary AC extending to the amplifier case. AC unlike DC will travel distance without problems.
If its a single secondary winding no problems, if you have two secondary windings their centre tap is probably best joining close to the bridge rectifier in the amplifier case.
So view the power supply as a source of secondary AC only.
At the amplifier case receive the AC straight into a fuse on its active then a switch then into a bridge rectifier and capacitors. Have all of your grounds return to the amplifier case chassis. From that chassis have a earth connection to mains earth. You could do this between the PSU and Amp chassis with a mains type lead -3 conductors in this case 2 wires are used for secondary AC and the other is the earth.
Cheers / Chris
hm.... mine is a separate unit now, but going to integrate into the amplifier case when i done all thing (after testing, evaluate, etc) But the power supply section (separate board) then pass DC into amplifier board (2 separate board for 2 channel). That is my current setting. (when you talk about it, seems many problem....... i hate to redo !!!
Mine is a 230V 120VA Primary, with 2 x 25V secondary. Using 2 diode rectification (center tap) since my amp is a single rail type.
Mine is a 230V 120VA Primary, with 2 x 25V secondary. Using 2 diode rectification (center tap) since my amp is a single rail type.
I do believe the forum rules dont allow us to even discuss double insulated. I have been chastised before for making comments regarding protective earth, that on reflection I maybe shouldn't have. While seeming a draconian rule, there are many on the site that have no electrical/electronics background, so its best not to discuss such things that if they go wrong, have no last line of defence, ie the protective earth connection of the mains.
If you can get hold of any books by Henry Ott, you will find a lot of information regarding grounding techniques (mains buzz is an EMC issue).
http://www.hottconsultants.com/tips.html
If you can get hold of any books by Henry Ott, you will find a lot of information regarding grounding techniques (mains buzz is an EMC issue).
http://www.hottconsultants.com/tips.html
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