Grounding thev Balanced line stage(BoSoz)

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I have just finnished stuffing my pre amp and bought all the other parts, so it is time to fire it up and put in in a cabinet.
But, I don't really have any education or knowledge in this field of the Diy world so I need some help to wire the unit to ground.

First of all, I live in Norway where we don't have ground at our ac outlets from the wall.

1. The grond from the ac cord, where do I connect this?

2. the ground from the powersupply, where do I connect this?

3. the ground from circuite board, where do i connect it?

4. I am building the power supply and circuits in two different cases, will this change anything on the grounding?

Hope you can answer me and help me to finally hear some music!

I suppose you start by making yourself an earth,possibly by using a thick insulated cable single wire which will go into your basement,and you fix it on a big copper pipe for used water.
Then you go to the local electronics store and buy yourself some CEE approved mains plugs,the"computer grade" ones with 3 pins.

Well,now you cable your mains and add the new created earthplug to the longest bit(should be up and in the middle).

Here you are for the basic setup :rolleyes:

I suggest to rely directly your PSU box to EARTH,I mean the chassis.Then use a strong wire to rely this to the Preamp's chassis :p
You should have a 60V symetrical supply,makes 3 wires.Connect them to the main board.

Next step:all your in/out plugs should be common for their Ground pin(external of a RCA socket for example).To do so,use a single wire 1mm dia. to rely all the in/out sockets GNDS together.
(choose some "insulated from chassis "type,with plastic washers.)
Now rely this with ONE WIRE ONLY to the GND socket on the main board,on the +/0/- 60V.You can wrap it around the cables to output sockets,for example.

Logically,if you followed all this you must examinate that the cables from the input sockets DO NOT HAVE ANY GROUND LINKED TO THE MAIN BOARD,at the input audio pins on the main board.

I hope I have been clear enough,sorry for the long thread,and if still not clear I suggest you to go on the ,where SYLEE did it and you would find a drawing he made on the Ground path in the preamp,very clear and he did it like that to avoid ground loops.


PS:I forgot just one thing:eek:n the PSU board,there is normally a power thermistor which links the GND to the real EARTH (the one you created going to the basement... :p
Is this right then?

Thank you for your respons!

But let me sum it up:

I make my self an earth like you suggested, infact it is only 2m from the water pipes, so that was a good choice:)

I then earth to the power supply chassie, and then from there to the pre amp chassie.

The chassie(or earth from the water pipes) will then be connected to the powersupply ground through the thermistor.

I then connect this ground(from the powersupply board to the circuite board.

Then all my balanced xlr plugs, both inputs and outputs ground pin should be wired together and then connected with a single wire to the circuite ground on the circuite board.

Now the section you wrote:

"Logically,if you followed all this you must examinate that the cables from the input sockets DO NOT HAVE ANY GROUND LINKED TO THE MAIN BOARD,at the input audio pins on the main board."

I don't really see the logic here, coul you please explain. Also, is the above correct?

THanks you very much,
Just a little warning when you make your own earth in a room, you are introducing a hazard. You now have a earth potentiall in your DIY-gear and other mains equipment in the room is not grounded so if any other equipment fails (life to chassi) and you touch it and your homemade earth: ZAP- lights out! and I dont mean the lightbulbs.
Here in Sweden you are not allowed to mix grounded and not grounded outlets in the same room.

Hope you get what I'm trying to explain.

I don't believe that groundin equipment is mandatory for good audio, though is preferrable. If you have a situation where some equipment is grounded and some not, this can be dangerous. So, if you decide to ground all you stuff and the preamp, make sure to have all chassies grounded to the same point either in a star or a bus configuration, but never have a ground loop. A ground loop occurs when you have a few pieces of equipment grounded chassie to chasse with an interconnect going to another grounded piece of equipment. You'll have a closed circuit from one ground through your equipment and through the interconnect cable to the other equipment, this almost always results in humming or interference with equipment.
Not good at all..

So if f.ex my cd player which is not grounded fails and shorts to case I will have all the voltage on that case,and the earth potensial in the preamp case, is this correct?

How would I connect the BoSoz without earth then?
As you see in the posts above I am having some problems:(

What if I use the cord from the bathroom so that all of the appliances in my stereo will be grounded, it won't be a problem then will it?

What if I use the cord from the bathroom so that all of the appliances in my stereo will be

The danger is still there if you have any other electrical equipment in same room that is not grounded, like a lamp. Say that this lamp short the main to its chassi (assuming the lamp have metal parts).the lamp will still be working but if you touch the lamp and your stereo at the same time you get electrecuted. If you dont understand the dangers involved with mixing grounded and not grounded stuff dont mess with it, you can get yourself or, even worse, someone else killed.
I dont know anything about electrical standards in Norway but it shoud not be so difficult to change the outlets and get them connected to protective earth (ground).
About the sonic side of your problema i know nada.

As the best bet, I believe it is best in your situation, not to ground the system to earth if there are other appliances in the room that aren't or won't be grounded. You should connect all the chassies together if the chassie grounds are not coupled with the rca or xlr grounds. If all the equipment in you system grounds the interconnect lines to the chassie already, then they are already common chassie when you have interconnects hooked up.
This will be safest in a room where there is no grounding at all.
Logically,the thermistor is here to protect your ZLS from internal accidental connexion to the Live AC line :)

But I think it is a crime for a washing-machine constructor not to provide safety connection from metallic chassis to earth :mad:

I think if there is no earth provided in your country,then constructors must have security laws to apply so it would never happen,however
I think best way to eliminate problems with kindda security rules is to install a very sensible differential ruptor,let's say 20mA between mains and earth,so in case of problems it will cut mains so no problem should occur with real live persons ;)

I think the question is clear now

Sorry for my bad english really if not clear!!!!


ok then

Even though there are just spotlights(buildt in the roof) as other electrical things in the room I will maybe cut the whole earth thing.

But, how should I connect the others then. THe xlr's ground, the powersupply ground(on the board), the circuite ground(on the main board) and the chassies.

Hope you can give an clear answer so I can finaly test this thing:D

And, thank you very much for your help!
Just as I told you in my first answer,but in that case put no earth...and pray for your AC main connections not to fail!!!Double check twice if it won't disconnect by any tracking force...or overheat due to short cuts,eventually...and always use totally insulated connexions with some heatshrink :)

Otherwise the lack of earth will not be so important.Should just give you some little hum when used single-ended outputs ;) ...and little voltage difference between your ZLS ground and earth,if you measure it with multimeter :p

Have fun!!!

Does anyone here run unbalanced only AND non-earth grounding? This is how mine will be.

Would like to hear if anyone experienced fatal hum with this configuration?

All parts are shopped and ready to be soldered, however I start to fear that I picked the wrong circuit for an unbalanced preamp. Hope not, cause I love this piece even though I haven't fired it up yet.

Ok then, summing up again..

I if don't have an earth I connect like this

-connect the two chassies together, power supply chassie and the main board chassie.

-connect the ground on the power boards to to the ground on the main board.

-connect all the xlr-grounds together and then connect this to the ground outlet on the main board as well.

Have I got something wrong?

I am sorry do be such a stupid ***, but don't wan't to mess it up( or myself:)

Norwegian Power Outlets

First:-I am norwegian myself, and-second: I work in the electronics/electric field.

Even old norwegian installations will have ground in the fuse box. Having the cable changed back to the fuse box is one solution to the problem.
Establishing your own grund wire will do the same job. If you have water based heating ( radiators) you can ground to one of those. Make sure you have a proper grounding clamp with the right dimension for the pipe you attach to.
If the electrical installation in your home dates back 10-15 years or so, it is a fair chance that your outlet has ground connected inside, but has a non-grounded cap that can be changed. Remove the cap and check, or have someone qualified to do it for you. The ground wire used in norwegian PR cables ( used in household installations) is usually non insulated copper or tin coloured.
If your wiring is more than 20-30 years old, think seriously about having new wiring and outlets installed, - at least get a quotation from an electrician....

OTOH- 99% ( or more) of hifi and video equipment in Norway has for years been used without ground, and I have never heard about accidents where the lack of grounding of hifi has been the reason. If you build your own, - you either have to trust your own skills, or have proper grounding installed.
If the msising ground has any impact on the sound remains to be seen( or heard). Norwegian power networks have untill quite recetly all been fully balanced ( no neutral), so the "polarity" of your power plug has no significance. At least until one starts to imagine things....
PSychoacoustics is a strange substance......... :p

BTW- latest revision of our regulations calls for all grounded outlets only.....
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