In the ’80s some tape manufacturers made magnetic tapes of sonic good quality but poor physical quality! I have restored a lot of Ampex 456 tapes from this period in my ‘oven’ which is a hairdryer and a thermometer. 6-7 hours at 50 degrees Celsius will take the water out of the glue and in almost every case the tapes will be OK for harddisk recording. I do not have tape recorders for every size of tape, but ½” with DBX noise reduction is no problem.
Inside the box. ‘Hovering’ tape.
When material is sampled through an AD converter, it is possible to remove a lot of the tape hiss and after that a normal mastering in 64 bit environment can be applied. Linear Phase eq. and Linear phase compression, real tube or tube emulation, maximizing and limiter takes over from here.
Here are some examples of a 4 track amateur recording, mixed down on Chrome cassette and copied to another Chrome cassette and stuffed away in a wet basement for 25 years:
Pre and Post: