The real benefit of a dedicated mains spur

Posted by: Steve Toy on 13 December 2002

Since I changed my B300 power amp for the B300XS (a bit like going from a 180 to a 250 in the world of Naim amps) I have noticed the aforementioned hardness in the treble with vocals which occasionally become slightly sibilant. It isn't all of the time though.

For example, this afternoon the system sounded sweet, open, rhythmic, and tuneful with an expansive and focused soundstage as I like it. The new power amp was definitely showing its worth.

This evening, some four hours later at around 6pm, the top end sounded really fierce with the very same recording. The soundstage had shrunk, and vocals sounded piercing. My new power amp is obviously revealing more of the shite coming into the system via the mains, or there would not be such a variation in sonic performance.

My understanding is that a mains spur will isolate a system from mains polution from other electrical appliances within a given dwelling.

Does it also keep the crap from outside your immediate home at bay?

I suspect that the biggest culprits of mains pollution come from around my neighbourhood, and not within my home itself. I could be wrong of course.

All thoughts on this matter most welcome.

Regards,

Steve.

Posted on: 13 December 2002 by dave simpson

Hi Steve,

quote:
My understanding is that a mains spur will isolate a system from mains polution from other electrical appliances within a given dwelling.

Does it also keep the crap from outside your immediate home at bay?

A reduction of noise from internal sources and no reduction of noise from external souces is the result of a dedicated spur. I believe the other benefit of a separate line is reducing the source impedance of the feed (bigger the breaker [with appropriately-sized wire of course], least number of breaks in the wire- outlets,connections, etc)= better sound.

Of course I'm not an engineer... so let's see what response we get when the morning crew awakens.....

hth,

dave

Posted on: 13 December 2002 by Steve Toy

Thanks Dave.

Indeed, lets see.

Regards,

Steve.

Posted on: 14 December 2002 by AussiePete

Well worth your while contacting PIC Australia (info@picaust.com), they have a mains conditioner/spike protector called "The Eliminator".It works exremely well at a ridiculously low price - approx Aus$450. It may not look like your lovely "audiophile" unit, but it works.
Hope this helps,
Pete

Posted on: 14 December 2002 by Mick P

Steven

A dedicated spur will undoubtedly clean up your supply and your system will sound much better for it. It is a very cost effective upgrade. I routed the cable myself and paid an Electrician to make the connections at both ends.

I suffered from similar problems to those you have indicated and fitting the spur has all but eliminated them.

Regards

Mick

Posted on: 14 December 2002 by Mr.Tibbs

“My understanding is that a mains spur will isolate a system from mains polution from other electrical appliances within a given dwelling.”

Only those appliances that share the particular ring circuit the kit is on will be partially isolated post spurring. I say partially isolated as they still all meet and ‘chat’ together back at the incoming feed, but the mains impedance is at its lowest there so the crosstalk is reduced.

A single 6mm spur will get all that shared crap of the line, but you only need identify what’s on the ring and temporarily unplug all of it to see if that’s causing the problem. A ring with everything unplugged bar the ‘sistem’ will give you a close approximation of a 6mm spur from a cleanliness point of view. Of course its impedance will not be nearly as low, then there’s all the terminations as it passes through the twin sockets, but it will still be pretty clean.

The big benefit of a spur is that it doesn’t have to circumnavigate the house, so for any given rating (say 30A) its impedance is going to be a lot lower. This is where much of the benefit of the spur approach kicks in, the lower the impedance of the spur, the less the bits of kit will interact with each other. The multi spur arrangement is king when it comes to dealing with interaction, as each piece of kit only meets at the point where the mains quality is at its best.

Mr Tibbs