Am I being Sneaky or stupid....or both.

Hi,
I have a major problem with a ground loop between my home theater PC and my HIFI.
Bazarly enough it is only if i connect up the un-grounded preamp as an intermediary, if i wire straight to the powers the buzz aint there.

anyway back to my question.

I have used every loop blocker i can afford, they help the problem but the buzz is still there.

The only solution I have is to place them on another mains ring. Unfortunatly i have only 1 socket mains ring in my flat and i could not afford another to be fitted.

Yesterday I got a (hopefully) splendid idea. My heating is electrical. I removed one of my storage heaters and am about to manually wire into that ring. It is a special heating only circuit in my flats. This means that nothing but heaters are connected to it...in theory really clean electricity (and heating electricity is cheaper in my flats which is why it is a heater only ring).

Compared to the drain of a 3kw heater the hifi will drain pittance.

Have i discovered a fantastic thing or am i overlooking something?

pros
1) Seperate ringmain to all the other inteferance causing electrical appliances in the building!

2) Cheaper electricity

3) that line is designed to have a huge drain on it so will be wired with better materials

cons
1) probably in breach of my electricity contract.

 

Er, storage heaters are usually run off E-7 power a separate circuit engaged by a switch in the meter. You might find the hifi only works from midnight to 7am...

 

... so it will sound better

might be easier to try removing a screen at one end of your interconnects.

 

Heh heh,

I forgot to mention that there are two heater circuits, on timed one 24 hour. I am using the 24hr one.

I have removed the screen on the interconnects, that just added a HUGE amount of distortion!

I cannot place what causes it.

I have re earthed all the components through one item - no effect.
I have fitted a DC blocker - massively reduced buzz but still there.

In theory there should be no ground loop in my system, but there is an undeniable 50hz buzz when my pc is connected to my preamp. this is of course whether my pc is on or off or whichever soundcard i use.

Hmmm, i just got a thought....why not ask rotel!

 

Is your PC connected to an antenna or cable TV? If yes, try removing the relevant plug to see if the hum goes away.

 

I used to get a big hum when I connected my PC to my system in the early days of my vinyl to CD transfer. I sorted it by switching off my monitor completely. might be worth a try too.

 

My PC is connected to an antenna, though the problem started before....i think......
this is something i have to look into me thinks.

Kenny K that might stop the hum but as I am using the pc to play DvD's it might ruin the effect somewhat!

 

Just a thought and i could be way off, but....when me and dad shared a system we had a problem with a buzzing rotel power amp ( new one ), it was underneath another rotel amp ( being used as preamp ). if you put your finger on one of the heat sinks it actually made it tingle, wierd.....so we phoned rotel who were very helpful and understanding. They thought it could be interaction between the two mains transformers and advised that we swop over the live and neutral on the power amp mains cable so they were 'out of phase' so to speak, the problem disappeared !

 

I had a nice chat to the rotel guy yesterday. He was very impressed with what I was aiming to do; which kinda surprised me. So i though i would pass it on incase there was any other interest.

Basically I am creating a home theater setup around a custom made SILENT pc, using the monitor output to a nice large tft monitor and my 5.1 hifi as sound. A fun though complicated aim.

He thought the problem would be down to my CD player.
To prevent a ground loop there can only be one ground in the entire setup. This is normally as simple as disconecting all your grounds but one (though remeber to reconnect if you alter the setup or resell)

Unfortunatly PCs tend to have false grounds, the case ground is not the same as the electronic ground and the wrong one is connected. The cd playere was my 2nd ground (which i forgot about). So removing that will hopefully fix it.
The PC ground is impossible to fix so I may always get a little buzz...grrr.

Oh well I am trying. using the PC and hifi earth on different spurs should help though.

Well that is all unless anyone else can think to add anything?

 

a biggish(2W or more) 100R resistor between the two grounds might work. worth a shot?