Genera mods...

Thank you for your replies Jon and Graham. I think you're right actually Jon, it would be wise to leave things unmodified until the turntable returns else I risk having no familiar reference to work from.

I'd read this and then consider such claimed benefits: http://www.compliance-club.com/archive/keitharmstrong/design_techniques4.html

One proponent of zero shielding argues that shielding reflects the magnetic field back at the conductors, thus causing feedback (negative and positive) which interferes with the signal...

In which case a printed circuit board is absolutely useless, and signal traces should be separated by massive distances... just picture your amp being the size of your room!

Also, you would not be allowed in it whilst wearing a metal zip fly, watch, or any other metallic article...

Neither would your speakers, turntable, any other signal source... or even any mains wiring!

All of these items could reflect back the magnetic field surrounding one of many signal conductors which make up a circuit.

But none of this is necessary because the magnetic fields are so tiny, and this is why sub-miniature items such as smartphones, tablet computers, sat-navs etc work, even with all their conductors so tightly bunched together.

The metal case being a conductor (the ground conductor - or even a "floating" one) is a considerable distance away by comparison.

Further info on this can be found here: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/wirfor.html and by plugging in real world values like 0.00001 in the "I₁" box and 0.0005 in the "r" box you should get the result which is an extremely weak magnetic field of 4e-9. Then, by all means, have a go with part two.

Let me tell you a short story... when I was aged 10 at school, we had to do a presentation on something we were interested in. I'd not checked my facts and told it the way I imagined it to be... it was met with howls of derisive laughter from the boffins of my class. Some "grown ups" in hi-fi seem to be doing exactly what I did at the age of 10. I learnt a valuable lesson that day: not to look like a complete tit!

"Materials technology in amplifiers: The DNM Series 3 Pre-Amplifier designed in 1984 saw the first use of construction materials that do not interact with the amplifier's magnetic fields. DNM are still the only ones doing this over 20 years later! "

I wonder why?


Edited by Graham Slee - 19 Jul 2014 at 9:56pm