Be sure that audio bypass condensers are not too small in value (accidently purchased the wrong value...say a .001 MFD instead of a .01 MFD), and be sure that tone condensers (condensers that bypass some audio to ground or from plate to plate in push-pull applications) are not too large in value. With modern condensers it is easy to accidently purchase the wrong values, and/or have someone send you the wrong values because they misread the value. Metalized film condensers often have their values listed by code. For instance, 473K would be a 47 MMFD condenser with three zeros after the 47, which would make it 47000 MMFD, which converts to .047 MFD. The K is a tolerance rating. If someone accidently sent you a 474K condenser, this would in fact be a .47 MFD condenser, or 470,000 MMFD. In a tone circuit, this would "muffle" the tone too much, and cause things to be quiet. In an audio bypass circuit, if you accidently received a .0047 MFD condenser where you needed a .047 MFD condenser, this would tend to cut out the bass notes and make the audio thinner and quieter.
Of course there are a ton of possible reasons as to why your radio is quieter, but these, and those mentioned prior to mine, are some of them.
Thomas