I did some testing - the scary way, connect and pray! Well, I can say that I managed to get rid of the ground loop. My solution:
I'm sorry for not being able to share the schemiatics, but I think they are available at Dantimax's homepage.
The serial connector has five pins going to common ground on JP5 (relvol3) and JP1 (input2). I disconnected these. The only ground connected was from the junction where the RCA ground connects to the input2 ground (which is common ground for input2 card). This means that there is only one ground from input2 to relvol3.
I don't how or why, but it is dead quiet even with 0 dB connected to source that is not playing. Seems like the problem is fixed.
I'm sorry for not being able to share the schemiatics, but I think they are available at Dantimax's homepage.
The serial connector has five pins going to common ground on JP5 (relvol3) and JP1 (input2). I disconnected these. The only ground connected was from the junction where the RCA ground connects to the input2 ground (which is common ground for input2 card). This means that there is only one ground from input2 to relvol3.
I don't how or why, but it is dead quiet even with 0 dB connected to source that is not playing. Seems like the problem is fixed.
low level bzzzzzzzzzzzzzzzzzzzz
Hi guys,
I finished my Aleph-P and its connected to a Mini-P. Here's the story;
With a bought pre, there's no hum absolutely dead quiet. But with the Aleph-P, I'm getting a very low level bzzzzzzzzzz (bumblebee flying kind of sound) coming from both tweeters. I'm pretty sure its not a ground loop?? You can hear it at about ~0.5 away from the speakers.
I tried switching to a single transformer winding as I thought it might be the capacitive parasitics from the transformer (searched from another thread) but it didn't help either.
Does anyone have any ideas? Or even where to begin?
Thanks all!
Hi guys,
I finished my Aleph-P and its connected to a Mini-P. Here's the story;
With a bought pre, there's no hum absolutely dead quiet. But with the Aleph-P, I'm getting a very low level bzzzzzzzzzz (bumblebee flying kind of sound) coming from both tweeters. I'm pretty sure its not a ground loop?? You can hear it at about ~0.5 away from the speakers.
I tried switching to a single transformer winding as I thought it might be the capacitive parasitics from the transformer (searched from another thread) but it didn't help either.
Does anyone have any ideas? Or even where to begin?
Thanks all!
as i find out now is the aleph=p has too much gain so the hum coming up if you put a post at the out put side,it will take the hum out . the input is for the signa in directly
please have a try the signa have to be big and aleph-p will do the amplification then the volumen will make the sound as loud as you like
please have a try the signa have to be big and aleph-p will do the amplification then the volumen will make the sound as loud as you like
Hi,
where do the input returns link into?
Similarly,
where do the vol pot returns link into?
I suspect when you add these, a few loops will become evident.
If this is the case then I think this could be solvable by separating the L & R audio grounds from each other and from the safety earth.
where do the input returns link into?
Similarly,
where do the vol pot returns link into?
I suspect when you add these, a few loops will become evident.
If this is the case then I think this could be solvable by separating the L & R audio grounds from each other and from the safety earth.
Hi,
if your ancilliary equipment connects any input or output ground to safety earth then your diagram will have a ground loop.
Similarly, if any pair of inputs or outputs have the returns connected together externally then again your diagram has a ground loop.
I think the only way to make your diagram work with all combinations of ancilliaries is to separate the left ground from the right ground and to resistively connect each audio ground to safety earth.
Is you star ground a copper/aluminium plate? Try individual solder lugs (one to every ground wire) bolted together.
if your ancilliary equipment connects any input or output ground to safety earth then your diagram will have a ground loop.
Similarly, if any pair of inputs or outputs have the returns connected together externally then again your diagram has a ground loop.
I think the only way to make your diagram work with all combinations of ancilliaries is to separate the left ground from the right ground and to resistively connect each audio ground to safety earth.
Is you star ground a copper/aluminium plate? Try individual solder lugs (one to every ground wire) bolted together.
rchua77,
I would cut off the gnd lines arranged btwn PS and the amp PCB.
If you need the gnd on the amp PCB, you send them directly to the star,
not through the PS board.
And, I'd like to recommend the thermistor btwn the SE and the star.
I hope the skech explains better. Good luck!
I would cut off the gnd lines arranged btwn PS and the amp PCB.
If you need the gnd on the amp PCB, you send them directly to the star,
not through the PS board.
And, I'd like to recommend the thermistor btwn the SE and the star.
I hope the skech explains better. Good luck!
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