Noise on aux input

After some years I decided to use the Aux input connectors on the Empeg for the first time. So, I put the Empeg in its sled and I connected a fully ok and working cd player.
Unfortunately, the result is very disappointing: the sound glitches. It seems almost like the Empeg input gets overloaded.

Just for clarity: I do not use the Empeg in a car (did that in the past, worked fine, did not check the Aux input) but I use it at home. The Empeg works fine without the sled. So, I put the Empeg in its sled to use the Aux input. The sled+Empeg stand on a wooden table.

I fiddled a bit around and found the following:
- tried another cd-player + a tuner: same issue
- when I touch the Aux in RCA connectors (cd-player not connected) I see in the VU info screen the needles moving to the right, indicating that the Empeg thinks there is some input. At that moment I can also hear some whine/noise over the speakers.
- when I touch the Aux in and the sled at the same time, there is no whine and the VU meters show no signal. When I do not touch the sled anymore the wine starts again and the VU meters jump
- It makes no differende whether I touch/use one or two of the Aux in connectors
- mp3's on the Empeg are playing fine, no whine or glitches
- all connections, the docking connector etc. seem to be fine

So, do I have a grounding issue on the Empeg Aux in? And if so, why is that the case since it seems very strange to me. May be some grounding wire came loose? Or am I not supposed to use the sled without grounding it? Or do I have to ground something else?

And how do I solve all of this? Just ground the Aux input RCA connectors to the Empeg by means of a thin wire? Or is it wiser to make a dedicated Aux in connection myself by connecting it in some way to the docking connector?

Thans for the answers, hope I can enjoy my new setup.

First, double check that the sled is wired correctly and that there's no faults in the connector pins.

If that's all fine, there could possibly be a internal hardware fault with the aux input circuitry on the player itself. If using the Aux is important to you, it might be worth sending to Eutronix.

You'll have to explain better what you mean by "glitches".

Hum/buzz/whine we understand, but glitches ??

For the hum/buzz/whine, the first thing to try is to place the empeg chassis (or the sled) in direct contact with the chassis of the CD player, or run a wire from one to the other, to place them both at the same ground potential. That will probably help.

You could even try the same with the amplifier, running wires from each of the three items to a common connection point to earth/vehicle ground. Ideally the same point from where the power supply ground wires originate.

cheers

The sled is wired as it came out of the factory since it is never altered. All connectors seem to be fine as i said before. I read the faq.

It is a mk2a.

'Glitches' means that the music is distorted every couple (say 5) of seconds for a second or so. It seams like there is an additional high level signal on the Aux in line at that moment. May be it is there all the time but only noticable at certain moments.

All equipment (Empeg, amplifier and cd-player) share the same power outlet (a regular 220V wall outlet). Aaah, now I see the cd-player is not grounded! And running the wire clearly solves the issue since this is the same as holding the sled and the Aux in connectors at the same time.

So, I quess I will just connect the cd-player and the sled by a wire. Ugly and strange, but it solves the issue.

Thanks for showing me that I had to connect the cd-player and the sled, that did not occur to me yet.

I'm confused. I thought you said that when you held the sled and the aux-in connectors at the same time, that there was no signal and the VU meters did not move. I thought that meant that the CD player did not work and did not make any sound when you did it. I guess I misunderstood what you meant.

If I'd known what you meant, then I would have suggested trying to ground the RCA shields right off the bat (as mentioned here).

Thanks, I missed that one in the faq.
And sorry that my english is not very good, I do my best but sometimes it must be unclear.