Framus Ruby Riot 2 scratching and popping noise

[Emetal]

Framus Ruby Riot 2 has scratching and popping noise coming and going EVEN WHEN all 12ax7 removed and no instrument cable attached. I resoldered all the power tube sockets just in case, measured all the reisistors, everything looks fine, not even a dust, it's pretty new amp. I do not have spare EL84 at the moment though, will get them soon. In the mean time I would appriciate any suggestions what else to check...

[Helmholtz]

Most likely a power tube issue. I assume the noise stops with all EL84s removed?

What is the cathode voltage?
Does it make a difference when you disconnect C99?

[Emetal]

Yes, the noise stops when EL84's are removed,
Cathode voltage is 13,2 vdc.
The C99 is as I see a cathode bypass cap, it is really hard to disconnect, there is no space to cut one leg, needs to be unsoldered from the bottom, I would have to disassamble all the tube sockets in order to get the Power board out and deal with it. Is that info really important or I could just wait for the new tubes and try with them?

[Helmholtz]

Cathode voltage looks good.
Let's wait for the new tubes.

[Emetal]

Just to confirm, it was the power tubes, after new ones are installed works perfectly for weeks now....