Siglent 1104X-E ground noise

[1audio]

I have an 1104X-E which mostly works great. However since a lot of what I do involves looking at low level signals I have a constant problem with this instrument- Pretty much whenever The DUT is grounded I have a high broad noise floor that messes with any trace below several volts. I did some careful checking and I'm getting about 25 mV of 50 KHz spikes between the scope ground and everything on my bench. Is this switching supply leakage? Does anyone else have this issue? Any advice would be appreciated.

[tautech]

I have an 1104X-E which mostly works great. However since a lot of what I do involves looking at low level signals I have a constant problem with this instrument- Pretty much whenever The DUT is grounded I have a high broad noise floor that messes with any trace below several volts. I did some careful checking and I'm getting about 25 mV of 50 KHz spikes between the scope ground and everything on my bench. Is this switching supply leakage? Does anyone else have this issue? Any advice would be appreciated.

Most likely but not from the scope.

Your task is to find where the interference is coming from. 

Screenshots as evidence please.

[Kean]

That sound like interference from a nearby SMPS.  The most common cause mentioned here is LED lighting.

Try turning other things on/off in a systematic way to identify the source.

[1audio]

I just checked and the power ground the scope is on is 10 Ohms from the power ground the rest of the instruments are on. I have some power distribution checking to do before locating noise sources (I have lots).

[1audio]

Thee real issue it turns out is intermittent connection in the probe shield at the BNC end. A small tug in the wrong direction and its open. Need connecting is 10 Ohms or more. All 4 probes show this problem. If I switched to a tek or HP probe the noise is much lower. Has anyone else had this issue with Siglent probes?

[Calambres]

Has anyone else had this issue with Siglent probes?

Nope! All the 4 probes for my 1104X-E work fine, 'though I must say that one of them was warranty exchanged because the 1x-10x switch was not working properly.