Sorry you are WRONG sort of, a 2 wire connection is needed. BUT the return can be through PE. You do not need 2 wires in the signal cable.
Connect your oscilloscope scope to power (assuming you have 3 wire power) and probe a signal without connecting ground from the probe. You WILL see the same signal with or without the probe ground. The scope return is through the power.
If the signal is conected to the chassis and the Chassis of both amps is connected to PE then you DO have a path for signal through PE.
This is where the OP has a problem he has TOO MANY paths to ground and not all are terminated at the same point.
I say again.
PE is for SAFETY only.
All audio equipment will operate without a PE.
I work at my bench with the transformer towards on end and the isolated LV stuuf near the middle.
I have no PE during the build and testing phases.
I have an amplifier under test at the moment without a Chassis. It has no PE. It works just fine.
BUT !!!!
break one wire of a two wire connection for the Signal Route and the audio will not work.
Break that route anywhere and the current stops. The audio stops.
PE is for SAFETY only.
All audio equipment will operate without a PE.
I work at my bench with the transformer towards on end and the isolated LV stuuf near the middle.
I have no PE during the build and testing phases.
I have an amplifier under test at the moment without a Chassis. It has no PE. It works just fine.
BUT !!!!
break one wire of a two wire connection for the Signal Route and the audio will not work.
This cannot work. A connection MUST allow current to flow around a route.
Break that route anywhere and the current stops. The audio stops.
Guys were are off track here the point is to help the OP.
PE can be return for signal but I never said this was ideal. In fact it causes noise.
Back to the original question.
You need to star ground the power amp. You have multiple paths to ground in your setup see pic 2.
If this was me I would connect the ground bar to the chassis and wire like in picture 1
PE can be return for signal but I never said this was ideal. In fact it causes noise.
Back to the original question.
You need to star ground the power amp. You have multiple paths to ground in your setup see pic 2.
If this was me I would connect the ground bar to the chassis and wire like in picture 1
Attachments
Hi
Tanx for the interest ( :
Im not gone use the PE, only using two wire powercable.
The signalcable is a two wire connection, signal and return connected at the amp PCB.
On the RCA, signal connected to centerpin. Return and shield connected together at RCA chassi.
Cut one wire and there will be no sound.
So what I ask is.
Must I isolate RCA?
Must I have stargrounding?
If so, the one and only chassi connection will be at the stargrounding?
Can I disconnect the cable that goes from groundrail to RCA chassi?
I have rerouted the amp GND cable to groundrail, before it was connected to the zero volt on the capicitors, this helped reduse the hum by say 25% at left canal and 50% at right canal ( listen at the speakers with zero volume ).
Frank
Tanx for the interest ( :
Im not gone use the PE, only using two wire powercable.
The signalcable is a two wire connection, signal and return connected at the amp PCB.
On the RCA, signal connected to centerpin. Return and shield connected together at RCA chassi.
Cut one wire and there will be no sound.
So what I ask is.
Must I isolate RCA?
Must I have stargrounding?
If so, the one and only chassi connection will be at the stargrounding?
Can I disconnect the cable that goes from groundrail to RCA chassi?
I have rerouted the amp GND cable to groundrail, before it was connected to the zero volt on the capicitors, this helped reduse the hum by say 25% at left canal and 50% at right canal ( listen at the speakers with zero volume ).
Frank
I second this the coax cable must carry both the signal and its return to the amp board, the GND should go to the amp board only.
Yes, this is absolutely correct.
Some shielded cables have a twisted PAIR of wires inside the shield. Probably not yours, though.
If the RCA jack is isolated from the chassis, the shield MUST be connected at both ends, unless there is a separate "ground" wire inside the shield that IS connected at both ends.
Then not coaxial. Screened twisted pair is not a coaxial, the second wire of the twisted pair is the signal return. One would never dream of breaking that return wire.
A coaxial has only the flow wire up the geometric centre of the coax. The screen forms the signal return.
That screen connection must not get broken.
H.Ott tells us to not use a drain wire version of a screened cable. Instead use a coax that has more copper in the screen.
Response in bold
Im not gone use the PE, only using two wire powercable.
NO you MUST have a PE ground if you are using metal case or you have danger of electrocution if power wire shorts to chassis.
The signalcable is a two wire connection, signal and return connected at the amp PCB.
The signal ground and the power ground MUST be started or ONE removed. It does not matter what people are saying here you only need ONE return. Muliple returns WILL cause noise. I have been doing this for 35 years so I do have experience in this area.
On the RCA, signal connected to centerpin. Return and shield connected together at RCA chassi.
May be ok.
Cut one wire and there will be no sound.
Why dont you try cutting the return signal at the RCA and see what happens
Must I isolate RCA
Not if you wire it haw I posted
Must I have stargrounding?
YES
If so, the one and only chassi connection will be at the stargrounding?
Can I disconnect the cable that goes from groundrail to RCA chassi?
ONE ground to RCA I would use signal first, see if this reduces or eliminates hum. If not use power ground and cut signal ground. (Remember power and signal ground are common at the amp PCB
I have rerouted the amp GND cable to groundrail, before it was connected to the zero volt on the capicitors, this helped reduse the hum by say 25% at left canal and 50% at right canal ( listen at the speakers with zero volume ).
You will need to experiment re-routing and removing grounds to fix this. Most people make the mistake of too many ground connections thinking this will fix hum.
My DIY amps have 1 ground point in each power amp and the preamp is isolated NO external ground except through power amps. My amps are quiet no audible noise.
Im not gone use the PE, only using two wire powercable.
NO you MUST have a PE ground if you are using metal case or you have danger of electrocution if power wire shorts to chassis.
The signalcable is a two wire connection, signal and return connected at the amp PCB.
The signal ground and the power ground MUST be started or ONE removed. It does not matter what people are saying here you only need ONE return. Muliple returns WILL cause noise. I have been doing this for 35 years so I do have experience in this area.
On the RCA, signal connected to centerpin. Return and shield connected together at RCA chassi.
May be ok.
Cut one wire and there will be no sound.
Why dont you try cutting the return signal at the RCA and see what happens
Must I isolate RCA
Not if you wire it haw I posted
Must I have stargrounding?
YES
If so, the one and only chassi connection will be at the stargrounding?
Can I disconnect the cable that goes from groundrail to RCA chassi?
ONE ground to RCA I would use signal first, see if this reduces or eliminates hum. If not use power ground and cut signal ground. (Remember power and signal ground are common at the amp PCB
I have rerouted the amp GND cable to groundrail, before it was connected to the zero volt on the capicitors, this helped reduse the hum by say 25% at left canal and 50% at right canal ( listen at the speakers with zero volume ).
You will need to experiment re-routing and removing grounds to fix this. Most people make the mistake of too many ground connections thinking this will fix hum.
My DIY amps have 1 ground point in each power amp and the preamp is isolated NO external ground except through power amps. My amps are quiet no audible noise.
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warrjon
I think about the PE, not normal to use it here. We have TN-system (Terra Neutral) in Norway.
Google: TN-nett.
I have only one return ( in signalcable ), Shield is not connected at amp PCB.
You say ground cable to RCA first, if noting helps. Cut signal ground and ground the stargrounding to chassi? Here is the cable I use.
Frank
I think about the PE, not normal to use it here. We have TN-system (Terra Neutral) in Norway.
Google: TN-nett.
I have only one return ( in signalcable ), Shield is not connected at amp PCB.
You say ground cable to RCA first, if noting helps. Cut signal ground and ground the stargrounding to chassi? Here is the cable I use.
Frank
Attachments
"It doesn't matter what people say. I'm right. They're wrong."
Doesn't that seem like someone's just plugging their ears with their fingers and repeating "neener, neener, neener"?
Signal returns (0 V) should be isolated from PE. With the use of a loop breaker between 0 V and PE, the noise from the ground loop will be significantly reduced, hopefully beyond the limits of audibility.
There is a heck of a lot of information earlier in this thread. One such tidbit:
Earthing (Grounding) Your Hi-Fi - Tricks and Techniques
Originally Posted by warrjon
The signal ground and the power ground MUST be started or ONE removed. It does not matter what people are saying here you only need ONE return. Muliple returns WILL cause noise. I have been doing this for 35 years so I do have experience in this area.
Sorry that should have read DC power ground NOT AC.. my apologies.
The signal ground and the power ground MUST be started or ONE removed. It does not matter what people are saying here you only need ONE return. Muliple returns WILL cause noise. I have been doing this for 35 years so I do have experience in this area.
Sorry that should have read DC power ground NOT AC.. my apologies.
Shield not connected at amp is good, the shield should only be connected at the ground end. This then acts as a guard to reduce induced noise into the signal.
It does not matter too much if ground is at RCA or grounding block as long as you DO NOT have multiple paths.
Also make sure you do not have AC power cables near signal or DC cables. If they have to cross make sure it is at near 90°
If the cable is co-ax the return must use that. Shields connected at one end are antennas and do not shield and thus do not guard. The signal and its return are best kept close together to minimise loop area and also to avoid them becoming a loop aerial. I would suggest looking at some of Henry Ott's papers and books, the return should NOT go via the power supply but directly to the input.
Also I would suggest some look at the stuff Jneutron has put up on his gallery.
