I changed the hard drive in my Mac and I was wondering if theirs any of transferring all the music on my iPad that wasn't downloaded from the iTunes store i.e. from imported CD's to my iTunes on my computer? The devices and account are the same as before. I tried it myself but it said to sync I'd have to erase all the content on my iPad.
iPad Air, iOS 9.1
Your i-device was not designed for unique storage of your media. It is not a backup device and media transfer was planned with you maintaining a master copy of your media on a computer which is itself independently backed up against loss. To use a device with a different setup you transfer the old library from a computer or a backup directly to the new setup, not the device to the library. Media syncing is one way, computer to device, updating the device content to the content on the computer, not updating or restoring content on a computer. The exception is iTunes Store purchases which can be transferred to a computer.
Redownload or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer - https://support.apple.com/en-us/HT201267 - "This feature works only for content bought from the iTunes Store." Does not do apps which must be re-downloaded directly from the Store.
For transferring other items from an i-device to a computer you will have to use third party commercial software. See this document by turingtest2: Recovering your iTunes library from your iPod or iOS device - https://discussions.apple.com/docs/DOC-3991 Even this method may not fully recover what you had in the library originally. For example if in order to save space when syncing you had converted music files to a lower bitrate, or photos to a lower resolution, it is those lower quality files you will recover.
If you subscribe to Apple Music, tracks which are not part of content your have purchased or uploaded cannot be transferred and have to be downloaded directly from iCloud.
New hard drive same account but iPad won't transfere
