hiss and osicilation problem

[slim_blues_boy]

yesterday I play my guitar that have been modified recently.
a custom made SG style guitar, it was repainted and the fingerboard changed to ebony.
I hooked it with fuzz factory clone into valve junior amp.
I use the fuzz factory to get clean into slight overdrive sound by rolling down the volume on guitar. the fuzz factory add some nice sparkle into the sounds and since the valve junior tend to be dark sounding it's great combination. I'm pretty satisfied with the result.

and then this afternoon I tried to play it again, but then there're hiss problem this time.
I thought it was bad solder joint problem, so I tried to resolder some of the connection.
but still it was hissy.

frustrated with the hiss problem, I changed the fuzz factory with 808 clone.
this time there slight hiss with the 808, but different problem occured. when I push the gain&tone to max level, it start to osicilated! and as far as I remember, it was never happen before!

two pedal that used to work fine before, started to behaved like that at the same time?!
well I started to think that the problem wasn't in the circuit, but something else.
but I don't have a clue what's wrong.