Floating Ground
- Thread starter Jamier
- Start date
You should consider providing a whole lot more info about what you're working on. Connecting shield grounds to audio ground does tend to defeat the purpose of the shield in the first place.
I was given a pair of K-501 boards by a friend. I built chassis for them with the intention of mounting the inputs off board. I have mounted RCAs on the chassis which require an input cable run of about 4 inches. The connection for the inputs,on the board, is about 4 inches from the PT. I concluded, possibly erroneously, that I should use shielded cable to connect the RCAs to the board. The circuit ground floats so I figured, possibly erroneously, that grounding the shield to the circuit ground would have no effect. At this point I intend to ground the shields at the ground on the IEC, but I do have concerns that they will pick up noise from the adjacent AC input.
Jamie
Jamie
At the IEC, connect the ground straight to the chassis. Wherever you have cable shields, connect them at the load end to the chassis. I would either connect the audio ground to the chassis right where that signal cable enters the board, or use a pair of anti-phase diodes to tie the audio ground to the chassis.
You want the diodes to be able to blow the fuse if the SHTF. I suspect a UF4007 would still blow a 1A fuse without trouble.
You could try it both ways.
If there's a local electronics shop, the diodes don't have to be anything particularly special.
If there's a local electronics shop, the diodes don't have to be anything particularly special.
What is the current fuse value?
Yes, you look at the datasheet for the diode and read the number for forward current.
I would stick with average. You don't want the diode to blow with the fuse!
At least a 2A rated diode, sure.
PB, If I use the anti-phase diode approach, can I connect the audio ground to the chassis at the line end or should it also be grounded from the load end, like the shields? What would yield the best result? I'm concerned that, just like the shields, there is a possibility of picking up noise from the AC input, even with the diodes in place. Connecting at the line end is easier, mechanically, but it's worth the extra work to do it from the load side if I am running the risk of greater noise pickup.
Jamie
Jamie
Less asking more doing! These are really low stakes experiments that take very little time to carry out!
