I think part of the problem is your understanding of ground. It can mean return as in speaker return or input return, just part of the signal path/loop. In a PSU the 0V is also called ground and here it is a current path from the transformer to the amp. PE is often called ground which is only for safety.
You could build a 6 channel amp with 6 PSU and 6 amp boards and they would work perfectly well without connecting them to a star ground or PE. The PE to chassis to amp connections are there to make it safe.
It is a mistake to connect the input grounds of the amps to the ground of the UCX. This gives you multiple loops. In your case use balanced inputs to break the ground loops.
You could build a 6 channel amp with 6 PSU and 6 amp boards and they would work perfectly well without connecting them to a star ground or PE. The PE to chassis to amp connections are there to make it safe.
It is a mistake to connect the input grounds of the amps to the ground of the UCX. This gives you multiple loops. In your case use balanced inputs to break the ground loops.
Do you mean just via the interconnects? How much would it help to bunch the 6 cables tightly together?
Yes, with unbalanced you haven't got much choice. Stammheim uses an additional ground connection between UCX and the amp's star ground.
Oh, I meant Vrystaat, sorry 😀
@Mark
What do you mean with classII??
Well, I tried connecting the linear power supply (UCX) to the gnd-star (not PE), and then connecting it to the UCX, and connecting the UCX-ps directly to the UCX. No difference.
OK, I have 2 big power supplies, which drive 2 amps per power supply. Furthermore there is one power supply to power the 4 LME49830 chips. There are two buffer-amps for the tweeters and one speaker-protection-board, which needs a common gnd to protect all the 6 speakers.
The UCX is powered by a linear power supply and the interface has to get connected using unbalanced outputs. How the hell should I connect it to avoid any problems? 😀
Could somebody use my drawings to replace connections? Sorry, I red the thread many times and I’m confused 😉
By the way… are symmetric power supplies with both separated rails easier to handle than centre tapped?
@Mark
What do you mean with classII??
Well, I tried connecting the linear power supply (UCX) to the gnd-star (not PE), and then connecting it to the UCX, and connecting the UCX-ps directly to the UCX. No difference.
OK, I have 2 big power supplies, which drive 2 amps per power supply. Furthermore there is one power supply to power the 4 LME49830 chips. There are two buffer-amps for the tweeters and one speaker-protection-board, which needs a common gnd to protect all the 6 speakers.
The UCX is powered by a linear power supply and the interface has to get connected using unbalanced outputs. How the hell should I connect it to avoid any problems? 😀
Could somebody use my drawings to replace connections? Sorry, I red the thread many times and I’m confused 😉
By the way… are symmetric power supplies with both separated rails easier to handle than centre tapped?
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https://en.wikipedia.org/wiki/Appliance_classes
Stammheim, I think you are misunderstanding my advice. Remove the star ground. Remove all the connections to star ground.
Stammheim, I think you are misunderstanding my advice. Remove the star ground. Remove all the connections to star ground.
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This complicates things, probably unnecessarily. Are you running them at an elevated voltage? If so why?
Mark, many thanks! I’ll try it out…
Scott, the LME-chip „needs“ <10V voltage more than the Mosfets to drive them optimally.
Scott, the LME-chip „needs“ <10V voltage more than the Mosfets to drive them optimally.
Only if you are wanting to drive them right to the power rails then yes, but then it would be better to add the extra voltage onto the main power rails for the chips and not have one separate supply powering all four chips.
It's just a first step, also, the UCX doesn't need a ground loop breaker as it should have no connection to PE.
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