I have a suggestion that won't cost you anything more than minimal shipping.
Audition a pair of NuForce Ref9V2 SE amplifiers. They are the quietest amps I have ever heard. You can return them for a refund, less shipping.
If you still have a hiss, then you'll know the problem is elsewhere.
Audition a pair of NuForce Ref9V2 SE amplifiers. They are the quietest amps I have ever heard. You can return them for a refund, less shipping.
If you still have a hiss, then you'll know the problem is elsewhere.