Need to connect pc to L1 compact tonematch VIA yamaha MG10XU

Hi Bose,

I need to connect my pc to a yamaha MG10XU mixer with a L1 compact tonematch as output. 

I have currently connected it with the mixer using an USB-A to USB-B cable. From the mixer to the L1 compact system, I am using a minijack to phono cable from the left monitor out (mixer) to the phono channel on the L1. I fear that this might be terribly wrong even though it seems to work. Lately I have been hearing an intermittent buzz when playing audio on the computer with L1 as the speaker as in the above setting. There is NO buzz however, when I am playing on my NORD stage piano which is also connected via channel 5/6 on the yamaha MG10XU. I fear that:

1. I have not established a balanced connection between the pc, mixer and L1 compact tonematch

2. My soundcard on the motherboard in the computer is dysfunctional.

3. I am using the wrong channels or cables

4. My cables are defect or the minijack to 1/4 inch jack is defect. I have been trying different cables and converters though, so this seems to not be the problem. 

Please help before i destroy my lovely L1 compact (I have of course stopped using this setup until I find out what is wrong) =)


Kind regards, 

Alexander Nørgård Alsing, Aalborg, Denmark

Original Post

Hi Alexander,

I'm having a little trouble following what's connected as you're not specifying what stereo, minijack, etc connections are on. However, here's how I would set it up:

  • PC to USB input on mixer (Ch 7/8).
  • All other inputs to mixer (keys, vocals, etc).
  • If the cable from the Mixer to the L1 compact requires less than a 25' cable, connect both Mixer Stereo outputs to the L1 Compact's phono inputs with a dual 1/4" TS Phone to dual RCA/phono cable.
  • If the cable from the Mixer to the L1 compact requires more than a 25' cable, pan each channel to one side and connect that side's Mixer Stereo output to the L1 Compact's 1/4" TRS input with a 1/4" TRS Phone cable.

If you still hear buzzing from the PC (is it a PC or a laptop?), then you may have a ground loop or noisy power supply bleeding into the sound card audio and would need a transformer isolator between the PC and the mixer. If so, you would have to go analog, i.e. from the PC/Laptop's 1/8" (3.5mm) headphone output into the mixer channel 7/8, placing a transformer isolator between them. The Rolls HE-18 hum eliminator works well for this (~$40), and has both phono and TRS/TS capable phone connections. I typically run a 3.5mm to dual phono cable into the Rolls and run a dual phono or dual phone from the Rolls to the mixer channel 7/8.


Hope this helps,

Hi Jeff,

I do admit that my whole setup sounds very confusing but your reply is very much appreciated especially with the super fast response. Thank you very much for this, I will surely try one or more of these solutions out and reply once I find out what works for me. 

I would like to add that my PSU is currently an old energon EPS-750w CM, and I am awaiting a new Seasonic SSR-850w FX, which I hope to enjoy (before my desktop pc disintegrates). 

Kind regards,

Alexander =)

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