Ground question

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi guys.
I'm building a stereo amplifier based on LME49830 300W/4ohms RMS boards, and the question is should/is it better to connect the whole aluminum enclosure to mains ground (earth) or is it prefered to be connected to the circuit ground? I always did this last choice in previous projects but you may contribute with your knowledge and experience in this regards. May both mains earth and circuit ground be hooked together as well?
:)
 
The Mains Earth connection (PE) should be bolted direct to Chassis.
Then the Loop Breaker (Disconnecting Network) can be bolted anywhere to the Chassis. It does not need to and should not share the same bolted fixing as the PE.

The 10r resistor does not need to be 5W.
You can use 10r 600mW or 500mW or 400mW or 250mW.
The 100nF should be a high frequency type, any small ceramic is good enough.

The Bridge Rectifier is shown with the ~ to ~ shorted and with the + to - shorted.
This places both halves of the rectifier in parallel and effectively doubles the current capacity of the diode bridge. i.e. 70Apk @ ~ 800mVf. It should also give a peak transient capability approaching 1000A.
This is my preferred method.
 
Thanks for your input Andrew. It's much appreciated.
I've been doing a little more research meanwhile, and found this variation of the set up above. Does it make sense regarding earth noise isolation? Seems like it does, but would like inputs about it.









158488d1266365341-alternative-method-loop-breaker-will-i-kill-myself-loopbreaker.gif
 
It is a basic safety requirement that all exposed metal parts of the chassis are *directly* connected to earth ground.

Directly as in 'directly'. With nothing in between. No resistor, no diode bridge, no mumbo-gumbo filtering network.

Don't fiddle with safety for the sake of some audiophoolery concerns.

********
In short: The first ground loop breaker you posted is ok, the second is not. Due to safety reasons as well as due to a remarkable amount of audiophile ******** in the explanations.
********

Andreas
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.