Better yet find a way to transfer it digitally to your HD and use sound forge or similar audio editing program to normalize the levels...never transfer via a headphone jack or other analog output when you have a digital option. Normalizing will magnify everything, so depending on how low is low on the master levels, you will also amplify noise as well but the results should be acceptable...there's no free lunch, so no matter how you do this there will be some level of increased noise but this will be your best bet to get an acceptable result. If you don't have the means to transfer digitally and can't find someone who can then transfer out of the line out (and not the headphone out) and then normalize, this will be your next best option.