[fsimms]

I posted a comment about power cords and ground loops here:


http://www.audiocircle.com/index.php?topic=61224.msg548727#msg548727

I thought that this might be a better place to get a technical discussion going about power cords and their improvements on music.

In the above post, I stated that in single ended systems that there are ground loops formed between the various audio electronic boxes.   I also stated that it possible to see the ground oscillations and properly designed power cords could reduce the oscillations.   

I would also add that with a CDP, a preamp and a amp there are ground loops between the CDP and the preamp, the preamp and the amp and a larger one between the CDP to the amp through the preamp.    If you try a power cord in this type of system then you can put it on the CDP but you still will have a ground loop from the preamp to the amp.  To tell if a power cord helps then you would need power cords on two of the three boxes to reduce the oscillations.

Bob

[NewBuyer]

Hmmm, so basically wherever a ground loop path is possible, troublesome radio pickup/resonance can also occur. 

I wonder if a solution exists that would essentially make all sufficient power cords perform equally: E.g. would an interruptor-style product like the EbTech HumX, or a in-wall filter like the PS Audio Soloist, perhaps defeat this potential problem?  Would using all balanced connections (when possible), and/or using high-quality line-level input transformers, also perhaps have any effect?  What about using a good isolation transformer at the outlet? 

Or perhaps the best solution really is to focus instead just on the power cords...

[andyr]

In the above post, I stated that in single ended systems that there are ground loops formed between the various audio electronic boxes.   I also stated that it possible to see the ground oscillations and properly designed power cords could reduce the oscillations.   

I would also add that with a CDP, a preamp and a amp there are ground loops between the CDP and the preamp, the preamp and the amp and a larger one between the CDP to the amp through the preamp.    If you try a power cord in this type of system then you can put it on the CDP but you still will have a ground loop from the preamp to the amp.  To tell if a power cord helps then you would need power cords on two of the three boxes to reduce the oscillations.

Bob

I agree with you that PCs have an effect on the music but I'm not sure I agree that "there are ground loops formed between the various audio electronic boxes". 

I suggest that if this is true, it is due to the mains earthing regime you use (or the equipment that you buy, uses).  If you are a DIYer, you can arrange the mains in your components so that you do not have ground loops with unbalanced systems. 

Regards,

Andy

[fsimms]

Perhaps somebody with more practical experience with the various solutions that are on the market than I can chime in.  I would need to look at the schematic of each solution to see what the advantages and limitations are.   I would also need to test them to make sure that I wasn't missing anything. 

In theory, balanced signals would be the way to go.  The only question would be the implimentation and if they had common mode rejection in the RF frequencies involved.  Shields for the balanced cables woud be another issue.  Steve McCormack said that input transformers were the best performers for balanced equipment.   

Although this is just an anecdotal story,  I tried my Minimax Phonostage against a battery powered Dodd phono preamp and the difference was great in the diffusion of the sound.   I was using a good power cord on the Minimax and tube dampers on each one.

[fsimms]

After mentioning Steve McCormack, I looked at his new stuff.  He sells adaptors for his new preamp for balanced connectors.  This seems to be an inelegant solution, but maybe necessary.  I suppose this adaptor is made so people could try lifting the ground on one end of the balanced cable.  These adaptors are supposed to work with his new preamp only.



EDIT: The RCA plugs on the preamp are true differential inputs and apparently are not tied to ground.