[LAU] Hum pickup in DI boxes

[Brandon Hale]

We have the Behringer x32 at the place of my work. Why not just use a 
3.5mm male to RCA L+R male out and plug into the aux input on the 
Behringer? That's what those inputs are for, right? That's what we do at 
work and have had success with it running small conferences with little 
to no audible noise.

I hope I'm not muddying the waters more here,

Brandon Hale

On 6/8/21 7:43 AM, Bill Purvis wrote:
> Not strictly a Linux problem, but I hope for advice.
>
> We're using a Behringer X32-Rack mixer for our church PA system. One 
> of the inputs that we need is
> for people to plug in laptops - usually via the headphone socket into 
> a Stagg dual DI box. We seem
> to get a lot of hum pickup on that, which I think is down to the 
> proximity to the laptops. We have
> another identical DI box at the other end of the room which takes 
> keyboard and bass and I've had no
> problems with that. Is there an alternative method we can try? We do 
> raise the ground lift switch on
> the DI box, which reduces the hum somewhat but still get enough hum to 
> be noticeable when nothing
> else is playing. I wondered if the matching transformers in the DI box 
> are acting as pickups for the
> RF noise generated by the laptops. The mixer on EQ display with RTA 
> shows noise across the audible
> spectrum, but most of the audible sound is mains hum.
>
> Bill
>