To Float or not to Float...

The most quiet amps I've used "float" the ground.  

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

Thanks, Jim.  I also use the preamp with a solid state amp that has no ground lifting switch, and keep the preamp switch in the "float" position.  Any danger in that?? 

@weebeesdad ,

No danger at all. The switch only lifts the audio circuit from the chassis ground.
(The AC mains safety equipment ground)

The AC mains safety equipment ground remains connected to the chassis at all times. In the event of a Hot to chassis ground fault event the safety equipment ground wire in the power cord connected to the preamp will carry the fault current to the wall receptacle equipment ground contact.

Are you using the preamp with the SS amp at the present time with the switch on the preamp in the float position?

I also use the preamp with a solid state amp that has no ground lifting switch, and keep the preamp switch in the "float" position.

Jim

Jim -
I have always used the preamp in the "float" position, whether it was with a solid state or tube (including the DeHavilland mono blocks) amp.  My impression was that sonically this was the preferred position, and as I mentioned the manual for the mono blocks even states a potential sonic improvement keeping the switches in the "float" position as long as there are no accompanying noises or buzzes (I can't seem to find the preamp manual to check, however it was planted in my head from somewhere (probably the manual) to keep that switch at "float").  Only recently did the buzzing begin which corresponded with some connectivity problems related to the preamp's power cord.  Now that I have switched to a different power cord, there is no more buzzing or noise, and all grounding switches are set at "float".