Rack mount MP3 players

[John M]

Can anyone recommend a rack mount MP3 player that can be mounted in the same rack as Wireless mic receivers without generating interference. I use a 4U rack with two JTS IN264 19" dual channel receivers in the two top bays and a Cortex HDC 500 in the bottom bay (DBX PRX between them but that's not used or turned on). As soon as I load up a USB stick to the Cortex the lower mounted wireless receiver picks up intereference on every frequency between channels 38 and 41.

 

I have previously used a pulse MP3 player but it did not have a very usable filing system for tracks - the Cortex lists songs by name, author, file name etc and has a very nice start from the begining of sound feature and XLR outputs (+ not required pitch change). Most important the Cortex had a good bright display and large illuminated start/stop button.

 

Is it possible that the Cortex has a fault that is generating wireless frequency interference or is this just a case that digital equipment always does this if in close proximity to wireless receivers. I did not notice this with my previous set up using channel 69 and 70.

[Andrew Edwards]

When you say your previous setup do you mean exactly the same equipment but with your JTS tuned to 69/70?

 

Is it definitely picking up on the RF as that is quite a wide spread.

 

Could it be coming into the audio side of things from a earthing point of view.

Does the same thing occur if you remove the gear from the rack and put it the same distance apart but insulated from each other?

[John M]

Hi - I dug out the old system (JTS 901 receivers) and noticed that the interference is also evident on them.

 

The new system is 2 x JTS IN264R (dual channel receivers on 19" rack) on Channel 38.

 

On further investigation the interference is coming from the front of the MP3 unit rack.

 

The antennas are front mounted but if I move them to the back the interference is reduced also if I move the mp3 player out of the rack I can make it disappear. I took the lid off the mp3 player to see if there was anything obvious - but nothing visual. I did notice that the case did not seem to be earthed but as it uses a 6v 3a external mains adapter I suppose this would be normal and it picks up the earth from the analogue output connection. - I am tempted to connect an earth to the case to see what happens - probably get an earth loop!

 

The rack is a Gator shallow rack but its not shallow enough for the antenna to protrude very far out of the back so rear mounting is not an option - although I have ordered a shallower rack from Thomann - who are very competitive with rack cases. I did consider swapping the units around so that the mp3 faces forwards and the receivers face back - but it is convenient to see the displays and these have a very convenient frequency synch button on the front which remotely changes the mic frequency

 

In fact the rack from Thomann is 2U so I suppose the easiest route is to just put the Receivers into the new rack and keep a distance between the two racks

 

 

 

quote name='Andrew Edwards' timestamp='1342080399' post='446076']

When you say your previous setup do you mean exactly the same equipment but with your JTS tuned to 69/70?

 

Is it definitely picking up on the RF as that is quite a wide spread.

 

Could it be coming into the audio side of things from a earthing point of view.

Does the same thing occur if you remove the gear from the rack and put it the same distance apart but insulated from each other?