how do I lift/not lift earth

[frank2395]

My mono blocks are to dificult to get into, 40 screws in total and work ok so I want to leave the amps alone;

My earth loop breaks when I lift one earth to amps.

I want to keep both chassis corectly earthed.(not one corect and other through an IC)

What can I put into my earth line that will allow it to flow when there is an emergancy but break the loop under normal curcumstances.

I can break into my earth wires (power cords) and but a box into the lead with components.

Can I put a rectifier (diodes) or a thermistor (inrush) in series with the wire to break the loop but give me protection

Will this work and or other sugestions please.

[kilowattski]

No, unfortunately any ground loop breaking device (thermistor or opposing parallel diodes) should be inserted between your signal ground and chassis ground, inside your chassis. The connection between earth and your chassis must remain unimpeded for safety's sake.

[frank2395]

I was hoping that would NOT be the answer, Thanks for your knowledge, I will just have to do the amps

[dnsey]

Why not lift the earth on one (or both) of the signal inputs?

[frank2395]

cables are non screened, negative carries signal return and is needed

[pinkmouse]

Try it, you might be suprised!

[frank2395]

Thanks so far.....but
the amps are silent without the loop,

Thanks Pinkmouse I think it is preferable to leave the return as apposed to using a long and possable dirty earth as my return (your opinion please)

Mr Kilowattski, is it better to have my earth interupted by the diodes or thermistor (to break loop) than to have no earth safety at all (your opinion please)

[kilowattski]

Frank,

I like the diode approach because the chassis can never have more than a 0.7 volt difference of potential from ground. Go to the passdiy.com website and look at the Zen IV .pdf file. You can see how it is implemented by looking at the power supply schematic in the Zen IV .pdf file.

[frank2395]

Mr Kilowattski,
Thank You,
following on from your comment in relation to mine:

I will break the earth wire in my power lead and insert a rectifier 35 amp +- in~~ out.

The amps will not be touched

Is there an advantage in http://sound.westhost.com/earthing.htm
method with a resistor and capacitor, I will not be having the conection to the chassis as he has but only have this circuit in the power cord

your opinion Mr K and please also Mr pass if you read this

[kilowattski]

Frank,

Negative on that one. The chassis must make direct connection to earth ground. If the path is interrupted, even by diodes you have a safety issue. The diodes must go between your amplifier ground and the chassis. Here is the diagram.