Re: [ARSCLIST] Aren't recordings original sources?

[Goran Finnberg <mastering@xxxxxxxxx>]

Larry S Miller:

>  I completely agree with your observation below about there being a
> audible difference depending upon electrical plug orientation (for
> two-pronged plugs.) On many units I was able to determine the "proper"
> orientation by running the back of my hand across the faceplate of a
> unit. If I felt a noticeable tingle, I'd reverse the plug and try
> again. Invariably, the one with the least tingle was the best
> sounding.
>  Now, I will say that some other people seemed less able to detect
> this than I, but we did do some blind tests and I was consistently
> able to identify the same orientation on those units which had a
> perceptible difference. Some units seemed to have no difference,
> perhaps those were better designed.

Power transformers have unequal primary to secondary capacitance on the
designated hot/cold connections.

This difference in leakage capacitance together with the 50/60 Hz power
frequency goves you a leakage current of a milliamp or so and this
varies with the amount of leakage capacitance depending on the
electrical plug orientation.

Then when equipment is interconnected using unbalanced interconnection
cables of the phono variety you will get common impedance coupling that
gives rise to warying levels of hum in the audio system.

Also since the incoming 50/60 Hz is severely polluted with RF,
Switchmode power supplies and switching disturbances from a few hundred
volts up to 10 KV for a few µS then this too pollutes the grounding
system in the amplifiers giving rise to subtle changes to the perceived
audio quality.

Here is a description of what is going on:

http://www.jensentransformers.com/an/an004.pdf

You can lessen the impact of this by using balanced power feed using
faraday shielded distribution transformers having 0.005 pF between
primary and secondary together with properly safety grounding of all
equipment AND always balancing the interconnecting cables between pieces
of equipment.

Here is just one reason why professional audio gear is always using
balanced connections.


-- 
Best,

Goran Finnberg
The Mastering Room AB
Goteborg
Sweden

E-mail: mastering@xxxxxxxxx

Learn from the mistakes of others, you can never live long enough to
make them all yourself.    -   John Luther