Thanks for the reply. I tried low-gain mod and it is almost as quiet as SS so it may not be the tubes. Mine 3A is brand new only 2 weeks old! I think it goes down to power supply or a mismatch with gain input from power amp. I have same problem with Conrad Johnson P350 and VTSP-2 but there is no low gain option to play with. Going back to 3A, it does have a much fuller body tan 2 and I have to madke do treatments to neutralise the bass. Anyway, my system has raised to another level and I have since been listening to it everynight, this is something I have not done for years!