No, not the fan. Replaced some components on the board, capacitors mostly I believe. I'd found the head a bit noisy (hiss mostly) from new through my EBS Proline 2000 2x10 and 1x15 cabs. I might have unwittingly bought a head that had a few poor components fitted at the factory, if as you say they don't normally have a reputation for being noisy.
Anyhow, when it used to get serviced, the tech suggested replacing the noisy components with what he reckoned were better quality ones to reduce the hiss. It definitely worked as it's mega quiet now and sounds the dogs, as it always did.