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To Float or not to Float...

I have a DeHavilland preamp which has a switch allowing one to "float" the ground.  I've always used it in the "float" position, however recently, perhaps due to some connectivity issues with my interconnects, there is a small buzz emanating from my speakers with the switch in this position.  The buzz disappears when I flip the preamp switch to the "ground" position.  Irrespective of the buzzing, is there any sonic advantage (or disadvantage) to "floating" the preamp ground in this situation??
Thanks for your informed opinions...

weebeesdad
georgehifi's avatar
georgehifi
10,312 posts
 
Whatever, you have your view, that has no other.

Cheers George
jea48
4,281 posts
 
John Curl does not lift the AC mains safety equipment ground from the chassis on the JC 1 amp.

"TECHNICALLY SPEAKING",     page 14
3. Use the Ground switch on the JC 1 to eliminate most ground loops. This separates the JC 1’s signal input ground from its chassis ground to isolate unwanted voltage in the ground shield of the unbalanced (RCA) input cable. Be sure your system installation is finished before you try moving the Ground Lift switch from its “Normal” to its “Lift” position.
https://parasound.com/pdfs/JC1Manual.pdf

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georgehifi's avatar
georgehifi
10,312 posts
 
"Be sure your system installation is finished before you try moving the Ground Lift switch from its “Normal” to its “Lift” position."
This statement proves my point, that then the amp circuit will get it’s system ground reference from the next stage via the interconnects shield, and if the shield were disconnected it could have large amount of noise and maybe even damage the amp.

Cheers George
helomech
1,513 posts
 
The most quiet amps I've used "float" the ground.  
jea48
4,281 posts
 
weebeesdad OP
54 posts                                                                            09-12-2017 12:48pm

Thanks for all of your responses. Cleeds triggered the solution when he (or she) wrote "a properly grounded power cord", which reminded me that I was having intermittent problems with the connecting plug of the preamp’s power cord. Swapped out the power cord and problem solved. I also have a pair of DeHavilland mono block amps with the same ground/float switches, and in the manual it states that leaving the switch in the "float" position may result in a "cleaner sound". At any rate, a fully functioning grounded power cord has done the trick...
@weebeesdad,

I checked and was told the ground lift switch lifts the signal circuit from the chassis/AC mains safety equipment ground.
The AC mains safety equipment ground is always connected to the chassis of deHavilland audio equipment for electrical safety.
It is recommended the user "float" both deHavilland mono blocks and close the ground lift switch on the preamp.

The chassis of the power amps will still be grounded, connected, to the AC mains power outlet safety equipment ground.

Jim

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