KEL84 rustling/crackle noise

Hi Folks,


My kel84 has developed what i would call a rustling/crackle noise from the left channel.

First of all I thought this could of been one of the valves but i've swapped them from left to right and the crackle noise is still there. Volume pot makes no difference either and audio still plays through the left channel.

It started yesterday after the amp had been on for about 3hrs. Just tried it again now and its still there although but not as loud......

Does anyone have any suggestions before i get the lid of and start poking around?

My first thought is that it maybe one of the ICAR PIO caps i have in the signal path the 0.22uf in c9/c10/c11/c12 (not got the circuit diagram in front of me so the c# maybe wrong).

The amp is just coming up to its first birthday so not that old at all.

thnx

Rich