[imported_Greg_R]

I am using an iPod / Headroom Cosmic combo at work and am having trouble with background noise. When I use the battery pack the amp is dead silent (i.e. perfect). When I use the standard wall wart I get a low background buzz. I am using Etymotic ER-4Ps so the Headroom's gain is turned -way- down. Should I

- Get the better $35 wall wart from Headroom
- Invest in a Basestation One (used ~$150) or the new desktop power supply from Headroom ($400). I would only want to do this if there were major improvements.
- Add a resistor in-line with my phones so I can increase the amp gain
- Other solution?

Note: Both the iPod and Cosmic amp do NOT have a ground plug. The noise level is lowered but not eliminated when I put the two cases together (ground differential is lessened).

 

[6seal]

I have the Cosmic and and Basestation 1 power supply. I also was getting some hum at home but traced it to a halogen lamp near by. Shutting THAT off took care of the hum. Since then I got a filter for the power line to the Basestation and all seems good. No more hum.

I would think that at work you've got electrical noise problems that a filter might fix. I've also noticed a tendency towards 'hum' when I listen to the iPod while it's connected to power through the pocket dock. I don't understand ground loop problems at all so if I've missed the mark through ignorance just disregard this post.

I DO recommend the Basestation 1. It's a definite improvement in the sound quality. I also use a low end Cardas power cord and filter (as I mentioned above). Whatever the hum turns out to be I believe the power cord upgrade will also improve the Cosmic's sound quality which is very nice to begin with.

Good luck.

 

[imported_Greg_R]

Thanks 6Seal. I will look into filtering the power at work...

 

[mfueger]

I have a Cosmic Reference powered by a BaseStation One through a Zu Buk PC fed by an IPod with docking station. I also have experienced hum when hooking the system up to my home stereo. Moving to a different power outlet completely eliminates the hum. I wish someone could shed some light on what causes hum and how to apply a filter or power conditioner to get the cleanest connection.

The BS1 is a clear improvement over the batteries and the standard wall wart.

 

[atx]

Get a ground loop isolator. You can find one at radioshack:

http://www.radioshack.com/product.as...t%5Fid=270-054

But you may not like the cables they use.

 

[mfueger]

Yuck!

I hope there are better solutions out there. This would really defeat all the good components and cables being used. I know, don't hammer it before you tried it, but they are sure causing my eyes to water, and I don't mean that in a good sense.

 

[fishski13]

Greg,
check out this good info here.

Quote:

The noise level is lowered but not eliminated when I put the two cases together (ground differential is lessened).

does this mean that both are properly plugged into the same outlet/powerstrip?

if it's not a ground loop causing the hum, i would suspect the wall-wart.

Skoal,
Corey