Cables from rack synth to A16 Ultra

[t_tangent]

Hi all,
Finally managed to sort out problems with getting no audio signal from outboard to A16u ins. Turned out the ADAT cables were the wrong way around and uots were connectged to ins Oops, oh well one lives and learns.
Which brings me onto the next question. I want to hook up a couple of outboard rack synths to the A16U inputs and am confused as the best way to do that. I have been using just 2 unbalanced cables from the synths line out 1 and 2 into my TL Audio EQ2 front panel instrument ins and the EQ2 is connected by balanced XLR out to XLR in on Scope plus whip. If I connect the synths line out directly to the A16u inputs inputs, also using upbalanced mono cable and with the A16u switches set to unbalanced mode, then it also works but I am getting a slight noise and hum, and the meters read about 60dbu. Is this normal. Would it be better to set the switches back to balanced or leave them as is.
Finally I need to buy some more cable but not sure if I need to get balanced jack to jack or will just mono jack to jack do and also how can I make sure all my kit is grounded properly.

Thanks for any advice on this

[hubird]

you can write a complete library on grounding aspects, and they did that already

normaly you have one thing in your studio grounded, normaly the mixer, but you could also think of the computer itself.
this way you avoid short circuits, which create hum (50Hz tone).

I would make sure grounding is ok before looking at the other problem.
In my studio there's not much balanced, actually nothing except my active nearfields.

Balancing can solve noise problems, but it's better to be sure your studio is technically perfect before 'solving' anything.
Balanced cable-ing is specially needed for long distance cables, or in circomstances of a lot of radio interferences.

Try the synth in another home/studio to see if something is wrong with it's internal circuit