Hello Griff!
You are plugging that into the Phono jack I hope

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However, knowing that you dd that, you'll need to get a phono preamp. Many amps that have phono inputs do not bring them up to the same line level. For an additional $100-$500, depending on your level of quality, you can have a phono preamp, which will preprocess and amplify the signal up to line level, and let you plug it in anywhere except the phono jack on your reciever.
Mitch