iPad bad sound quality and week loudness

[filipg96]

Hello,
I've bought an iPad 1st generation 64 GB. I'd like to connect it to my amplifier but the sound is very quiet and bad quality. What's wrong ?
I've tried with my iPhone 4 and everything is OK
Please help
Greatings

 

[BrianBaughn]

Check all volume (loudness) settings on the iPad and the apps you're using and, most importantly, try a different cable.

 

[filipg96]

I've tried that with two cables. All settings are ok and i think that App doesn't do anything wrong. I hale jailbreak.
Maybe should I restore it and check on clean OS ?
How does the sound loudness from iPad compare to sound from iPhone 4 normally ?
Thanks