Why does a cd player need a clean power supply?

[ALW]

First of all why does a company use switchmode powersupplies? The only reasons are cost and mandatory idle power consumption regulations. As long as a CD-player performs well enough it is good enough. This is certainly not the same objective as striving for the best audio quality. So a good analog power supply is the best. See the comments of Guido regarding EMC

There's a number of other reasons too that I can think of: -

Ability to cope with wider i/p voltage range, improving consistency of performance is one, another may be the possible benefits of using a power supply that can be charged at a rate faster than the audio demands placed upon it, unlike conventional supplies.

There are a number of downsides though, EMC being the primary one. The EU EMC reg's are useless in this regard, not defining the maximum emission levels across the audio band!

Items such as the Linn CD12 (at least early samples) place large amounts of such noise back onto the mains, which can significantly pollute the supply to other items of equipment.

I have a gut feeling though that if one applied the same level of attention to detail on an SMPS supply as many have applied to a linear unit, it could work very well indeed, but would be very much harder to design.

Andy.

 

[Guido Tent]

There are a number of downsides though, EMC being the primary one. The EU EMC reg's are useless in this regard, not defining the maximum emission levels across the audio band!

Items such as the Linn CD12 (at least early samples) place large amounts of such noise back onto the mains, which can significantly pollute the supply to other items of equipment.

I have a gut feeling though that if one applied the same level of attention to detail on an SMPS supply as many have applied to a linear unit, it could work very well indeed, but would be very much harder to design.

Andy.

EMC regulations are not meant for audio, but for decent and safe functioning of equipment.

And yes, SMPS's are quite flexible towards mains, heat and so on. But they kill the music.....

Main problem is that one cannot reduce the RF energy, one can only reduce currents or voltages.

regards