my 1987 have a strange NOISE like phase.
when i use clean,everything is ok.
but when i turn up volume(use thd hotplate)to get overdrive tone.
every note's fermata(or sustain??)will become "FLOAT".
just like i use the phase padel.
this noise is not very serious.but you just can hear it.
i have try to change the tubes,but still the same.
my english is not good,hope you can understand what i mean.
THANKS!