Let's make this easy:

Danny - report back with the model number(s) of the mixer and/or amp section of your PA. I'm guessing you have a powered Yamaha mixer; but perhaps not, maybe you have powered main speakers, or completely separate components.

Yamaha has nearly all of their user manuals for their series of products up on their website. After a short download, we'll get to see what inputs are available.

There should be a Tape in set of RCA connectors, or a set of stereo line-in connectors on 1/4" jacks if there's a mixer of any type involved, built-in amp or not.

However, this doesn't mean that your laptop has equivalent output at the headphone jack as what your old lappy did; even with all software controls set the same for the output volume. I've experienced this myself - even among the same name brand. Fact of the matter is, there's only a few actual lappy builders in the world that OEM them for all the brands and one particular brand doesn't always buy from the same maker. I don't think this is the case with Lenovo - pretty sure they are one of the brands that actually builds their own.

But, with that said, there should be sufficient make-up gain available in the mixer to account for a mismatch - so as to avoid remixing all of your backing tracks.

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