I have tinnitus and passed the hearing test easily.
I have had tinnitus for almost 7 years now. I am told I have it because I have flown for 30+ years but no-one knows for sure how I got it. None of my relatives have tinnitus. I have never been a frequent visitor to clubs and infact avoided loud music because I have always disliked loud sounds. I retired from flying aged 55, 3 years ago. The tinnitus has not prevented me from sleeping normally.
The ENT consultant told me I have the usual pattern of damage to the cochlea that long term flyers sometimes get. I do not suffer any loss of hearing and only have tinnitus in one ear.Some days it is fairly bad and other days I can hardly hear it. Stress makes it worse.
I am married to a medical doctor who thinks a lot of younger people will get tinnitus at an earlier age now that so many audio advices are available that are used with the volume set at a dangerous level. I get quite a bit of info on the subject at home.
Tinnitis is almost always the result of over exposure to loud noise or a continual exposure to a certain constant noise level over long periods of time.
The maximum allowed decibel level in industry is 80 dB for a duration of 8 hours.
My tinnitus started for only 10 seconds at a time and then wore off and returned some months later over a long period of time. It has gradually got worse over about the last 3 years. It is true what someone else has said, in some people the brain realises it is a sound that is not beneficial in anyway and the person no longer hears it. That happened to someone I know who had severe tinnitus and loss of hearing due to riding loud motor bikes. He had tinnitus for 7 years and one day it suddenly went, he is very hard of hearing though even though he is only 30.
As a basic rule if you have to raise your voice in order to be heard over any loud noise or music you can damage your cochlea (inner ear) permanently. Other people who get tinnitus do so because they have high blood pressure or inherit the defect from a parent.Currently there is no cure for tinnitus.
A further common problem some people develop when they suddenly get tinnits is a phobia of noise and wear ear plugs when there is absolutely no danger to the noise level they are exposed to. They usually overcome that phobia in time.
I would not use that ipod if I were you but am sure you will get pass your medical without any problems.
Best of luck