[HandCrafted Lab]

Originally Posted by Virtalahde

HCL's products look great, and I have no doubt that they sound great, too. I use some of those components myself in my own equipment.

However, I can see that there is a ground lift switch near the IEC (power) connector in some of the products. At least in the Distortion Box I can see it disconnects the safety ground from the chassis (or whereever that red cable goes from the switch).

This is not legal in most countries, and it is extremely unsafe.

Hehhhhhhh...... so, in turn we have two questions -

-are you professional circuit designer, DIY designer,device maker?
I have assumption - yes,since you have mentioned usage of same components.
But... how professional engineers (with career more than 25 years as device maker and studio engineers) who able to build devices with perfect sounding,make matching of superb tubes and finest modes of tubes, design of unusual circuits - how same these engineers not able to design grounding chains correctly?

If all the ground lift switches are in and a live mains AC voltage comes in connection with the chassis, the chassis will conduct the mains voltage to your fingertips.

You have used two correct key words - If... & And.
It`s alike - "your car can (or must?) to explode because car engine use gasoline - which is flammable". Yes,of course - if you smoke near with gasoline tank or push the stub/match into this tank.... (yes-yes, with cry - O... my God! )

So, if this switch is installed - it assume two variants - IEC grounding or external TRUE grounding - yes, through metal plate like 1x1m buried into true wet earth near your studio and connected by thick copper wire/buss like 20-30mm2 to chassis of stuff. It`s different things if you have assumed that it is same.

So, next question - I hope you never tried to use IEC grounding and true "ground" grounding simultaneously?

The safety ground from the IEC connector is supposed to go straight to the chassis. The signal ground can be lifted safely.

Yes, and this switch connect IEC ground pin to the chassis directly - if need.
But colleague - IEC rules not describe ground & digital loops, hums/noises for studio audio devices. Look, it`s not chinese teapot,razor or toaster.
Ground pin in the IEC socket is not grounding actually. It`s zero bus,in addition to hot and cold power lines. This zero bus can help to avoid an electrical shock but this zero bus has widest spectrum of noises from different sources which is grounded through same IEC grounding across your power lines - from all your digital devices in studio to welder machines and lathe on the nearest plant,drills,microwaves etc near of your location.

So... this switch is intended for disconnection of the chassis from "dirty" IEC grounding and connection the device chassis to the true grounding,in the earth,without "garbage".
If result is important of course.

I can surprize you also by difference like in 30-100V between IEC grounding and "earth" grounding. So, your solution?

Therefore... never use both variants of grounding simultaneously - firstly it has not any sense,secondly - you will not damage stuff and save money.
Single variant of grounding only - through IEC socket or through "earth" grounding.

And thrid question - whether you have knowledge of Phillip Newell grounding topology for the studio?