I have 2 keyboards that I want to connect to a powered mixer Work Kronus PRO 6500. The mixer has 6 mono inputs and 2 stereo RCA.

First keyboard is a Korg that has 2 outputs L (mono) and R. This one I'm connecting to the mixer with a mono cable 6.3 jack cable and everything works OK.

The second keyboard is a Yamaha PSR-550, this one has only one output (stereo I'm guessing). The problem is that when I'm connecting with the same cable no sound comes out from the speakers. This is what I don't understand. Shouldn't some sound still come out?

How can I make this setup work? Can I get a stereo cable with a splitter to 2 mono jack and insert in 2 inputs of the mixer? Or should I get a cable 6.3 jack to RCA and use one of the 2 stereo inputs of the mixer?

1 Answer 1


Make sure your instrument cables are in working order by swapping them out. If no stereo plug is needed from the Yamaha it could be the cable that is the problem. Make sure they are instrument cables and not speaker cables.

If the instrument cable for the Yamaha came with the Yamaha, look to a plug to check for stereo or mono. Stereo will be TRS (tip ring sleeve, or three sections and mono will be TR (tip ring or two sections to the prong of the plug).

Yes, you can get a Y adapter cable that will convert a TRS (tip ring sleeve) single plug to two TR (tip ring) plugs. The two channels receiving the signal can be full panned L and R for stereo or pan to center for mono.

You are guessing the Yamaha output is stereo. Single jack stereo connections use TRS (tip ring sleeve) 1/4" plugs. Two jack stereo connections use TR (tip ring) 1/4" plugs on two instrument cables. If the Yamaha is not stereo then use a TR (tip ring) single instrument cable to make the connection to one channel.

The RCA input is most likely not be compatible with the impedance of the keyboard's output.

  • Thank you for answering. In the end I gave up on using the Yamaha. I want to ask you, what is the difference between speaker and instrument cable? Aren't they the same TR type of cable? Nov 8, 2023 at 16:18
  • The manual (usa.yamaha.com/files/download/other_assets/8/336078/…) says the output jack is stereo and line level. When there's a cable plugged into that jack the speakers on the keyboard itself will be shut off so the only noise you'll hear is through the mixer. With a 6.3mm Stereo (TRS) to RCA cable you should be able to get it to work.
    – Duston
    Nov 8, 2023 at 17:28
  • An instrument cable is a shielded type. Inside the insulation is a wire mesh that encases the center insulated wire. The mesh acts as a barrier to interference. Mic cables, guitar cords, powered speaker cables, cables for keyboard outputs etc. are all instrument cable types with woven wire surrounding the center wire.
    – ejbpesca
    Nov 11, 2023 at 19:53
  • Speaker cables do not have the mesh shielding. They are made up of two similar wires and should only be used for connecting an amp head to a speaker. Both have tip ring plugs.
    – ejbpesca
    Nov 11, 2023 at 20:05

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