Bottlehead Forum

General Category => General Discussion => Topic started by: audiophileboss on September 12, 2013, 01:28:47 AM

Title: Out board power supplt too close?
Post by: audiophileboss on September 12, 2013, 01:28:47 AM
Some one told me that I cant leave my outboard piwer supply to close to my amplifier. Is that merrit?
Title: Re: Out board power supplt too close?
Post by: Grainger49 on September 12, 2013, 01:57:30 AM
Boss,

The reason for an outboard power supply is almost always to put some distance from the noise/hum causing AC and the DC that the component runs off of.  Hum is reduced by the square of the radius. 

If I were you I would try moving it a couple of feet from any analog component and see if the noise in the system drops. 

The outboard power supply of my Foreplay is a couple of feet away, I can't hear any noise.  I tried moving it the full four feet of the umbilical and it didn't make any difference.  There is a point at which more makes no additional difference.
Title: Re: Out board power supplt too close?
Post by: audiophileboss on September 12, 2013, 02:02:18 AM
Thanks, will try that
Title: Re: Out board power supplt too close?
Post by: Paul Birkeland on September 12, 2013, 04:44:12 AM
Sometimes the existence of an outboard power supply may be due to insufficient space inside the amplifier, or just plain silly overall weight if the two were combined.

Remember - the vast majority of power amps do not have outboard power supplies.
Title: Re: Out board power supplt too close?
Post by: audiophileboss on September 14, 2013, 03:20:09 PM
What about power conditioners? Same rule? And only amplifiers, not cd transports or dacs?
Title: Re: Out board power supplt too close?
Post by: Grainger49 on September 15, 2013, 08:05:56 AM
Going to the first question.  The statement has merit.  Bottlehead transformers are wound with shielding, still they are as far away from the audio circuit as possible in the layout.  If your piece with the outboard power supply has the transformer near the audio circuit the same thing applies.  Otherwise the umbilical would be 4" long.

I would guess that most power conditioners are well shielded.  However, you have power cords, try it.  First put a meter across the speaker leads, turn up the volume control so you get some reading on the meter.  Then move the outboard power supply or conditioner away from the audio components.  See if the noise level drops.

Seems easy enough and really cheap to try.