Banned
Joined 2002
Banned
Joined 2002
Banned
Joined 2002
Yes..
I know, ground is ground on this amp. Power/signal/speaker are all the same potential. You could change your speaker ground to anywhere on the chassis that is ground and I don't think it would make a difference. There are 2 speakers, one has nothing to do with the other, therefore there can be no loop associated with the speaker grounds.
Iwould really try a series groung on power and signal. It won't take long, won't hurt anything, and worked for me
I know, ground is ground on this amp. Power/signal/speaker are all the same potential. You could change your speaker ground to anywhere on the chassis that is ground and I don't think it would make a difference. There are 2 speakers, one has nothing to do with the other, therefore there can be no loop associated with the speaker grounds.
Iwould really try a series groung on power and signal. It won't take long, won't hurt anything, and worked for me
Banned
Joined 2002
mpmarino said:Yes..
I know, ground is ground on this amp. Power/signal/speaker are all the same potential. You could change your speaker ground to anywhere on the chassis that is ground and I don't think it would make a difference. There are 2 speakers, one has nothing to do with the other, therefore there can be no loop associated with the speaker grounds.
Iwould really try a series groung on power and signal. It won't take long, won't hurt anything, and worked for me
I'll tryit tonight see what i com up with. .I dont think it will work but hey it's worth a try.
Banned
Joined 2002
Not to the humm:
> http://jleaman.ath.cx/aleph/testing-psusm.jpg
The load (the speaker) could have high currents.
If you ground it through the PCB, and that PCB point
will be the signal GND, there can be a problem, namely:
imagine a high current on that green speaker ground wire and
maybe some RFI too, cause the speaker cable acts as antenna too.
And imagine that the green wire from the amp PCB to the PS PCB
has a resistance, and a high frequency impedance. Now when the
high current, and the RFI arrives from the black speaker terminal,
it wont go directly to the main PS GND, but partialy remains, and
that will be the polluted signal GND on the PCB...
So The speaker GND should go directly to the PS PCB, and an other
GND wire should go from the PCB GND to the main PS GND.
> http://www.diyaudio.com/forums/attachment.php?s=&postid=903018&stamp=1146205602
So if your speaker GND is now going from the terminal directly to the PS GND,
you should route your output from the amp paralell with the PS rails back to
the PS PCBs top, and then the 2 speaker cable will go from that point to the
terminals. I hope thats clear.
To the humm:
Otherwise on this picture the signal cables are too near to the high impulse AC section,
and if I'm right, there is a great groung loop in the middle, created by the two signal
cables (because at the source the gnds are connected likely) and through the PS GND
wires, there is another connection, so the loop is created, and the PS is in the middle
of that loop.
Try to put the signal cables from the other side, where the built-in RCA-s already are,
and you could try, that the signal GND and the PS GND is connected right from the RCA
to the PS PCB GND, like on my attached picture.
Where your heatsinks are connected to ?
Do you conencted the safety earth somewhere ?
You should try to conenct these together. First trough a wire, and then through
a resistor, then through a series RC, a paralell RC, etc....
Good luck !
> http://jleaman.ath.cx/aleph/testing-psusm.jpg
The load (the speaker) could have high currents.
If you ground it through the PCB, and that PCB point
will be the signal GND, there can be a problem, namely:
imagine a high current on that green speaker ground wire and
maybe some RFI too, cause the speaker cable acts as antenna too.
And imagine that the green wire from the amp PCB to the PS PCB
has a resistance, and a high frequency impedance. Now when the
high current, and the RFI arrives from the black speaker terminal,
it wont go directly to the main PS GND, but partialy remains, and
that will be the polluted signal GND on the PCB...
So The speaker GND should go directly to the PS PCB, and an other
GND wire should go from the PCB GND to the main PS GND.
> http://www.diyaudio.com/forums/attachment.php?s=&postid=903018&stamp=1146205602
So if your speaker GND is now going from the terminal directly to the PS GND,
you should route your output from the amp paralell with the PS rails back to
the PS PCBs top, and then the 2 speaker cable will go from that point to the
terminals. I hope thats clear.
To the humm:
Otherwise on this picture the signal cables are too near to the high impulse AC section,
and if I'm right, there is a great groung loop in the middle, created by the two signal
cables (because at the source the gnds are connected likely) and through the PS GND
wires, there is another connection, so the loop is created, and the PS is in the middle
of that loop.
Try to put the signal cables from the other side, where the built-in RCA-s already are,
and you could try, that the signal GND and the PS GND is connected right from the RCA
to the PS PCB GND, like on my attached picture.
Where your heatsinks are connected to ?
Do you conencted the safety earth somewhere ?
You should try to conenct these together. First trough a wire, and then through
a resistor, then through a series RC, a paralell RC, etc....
Good luck !
Attachments
Banned
Joined 2002
> the gnd from the main input AC goes to the center of that psu board
Try to disconnect them!
> The speaker GND's go to that center too. And now the rca GND's go to that exact point also.
And do you have any direct GND connection from the PCB the that point ?
Could you post an updated picture of your layout please ?
Try to disconnect them!
> The speaker GND's go to that center too. And now the rca GND's go to that exact point also.
And do you have any direct GND connection from the PCB the that point ?
Could you post an updated picture of your layout please ?
Banned
Joined 2002
Banned
Joined 2002
jleaman said:
And after try to use a resistor paralelled with a 47n-100n cap with it.
In most cases hum is created not by ground loops, even if they exist,
but by the mains in a capacitive based way and not earthed properly...!
And of course what jh6 said. I didn't mention you use a GND point at the start of the PS PCB...
Banned
Joined 2002
I'll post progress tonight. Ive been busy working on my shopping cart that im about to release and making cables for people
here is a sneek at the cable.
here is a sneek at the cable.
An externally hosted image should be here but it was not working when we last tested it.
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