Re: [ARSCLIST] Audio equipment cable shielding

[Don Cox <doncox@xxxxxxxxxxxxxx>]

Hello Robert

On 19/04/06, Robert Hodge wrote:
> I have used nothing but MOSFET based power amplifiers for years. David
> Hafler is one brand I can recommend. I have a second in the other
> listening room , but can't remember the brand.It is used extensively
> in motion picture theatre sound systmems.
> 
> Unfortunately, there are no consumer level devices that I know of
> which use balanced inputs. Balanced inputs and outputs are usually in
> the domain of professional level equipments.

They are beginning to appear. For example, Cambridge Audio announced
their 840XD amp, with one pair of XLR inputs (the rest being phono
jacks). At around $1000, this is mid-level consumer grade.

 
> There is one thing that comes to mind though. If you have a receiver
> or other device with a poorly designed and shielded power transformer
> too close to your turntable, the transformer can easily induce hum in
> the pickup. Moving the offending device far away enough to eliminate
> that source of hum will just be defeated by the hum pickup from the
> too long signal cables from the turntable.
> 
> Catch 22 above !
> 
> That's why my power amplifiers are well removed from the turntable
> area. And they have properly shielded transformer. Ditto the preamps.

Regards
-- 
Don Cox
doncox@xxxxxxxxxxxxxx