Revibe - ticking noise trouble

[Joobacz]

Hi guys!
I've got a quest for you. I need help finding a troublemaker inside of my home made Revibe (by Jeff Gehring). I've already built one tube amplifier (Fender 5F2a) few years ago so I have some experiences but this circuit is more complex and I've already tried all my tricks without any success. Here's the thing...

When it's on and plugged into an amplifier it makes intensive ticking noise like in video below but the noise is way more louder and I can regulate speed and intensity of it. Even I can add a reverb to this ugly sound but guitar signal doesn't pass through.

The noise is hearable even when the revibe is NOT plugged into an amplifier. It sounds like when tubes are getting warm but the sound goes from the reverb tank.

When I'm measuring voltages on tubes and I touch pin 1 or 6 of V5 with my voltmeter the clicking noise stops. When I touch pin 3 or 8 of the same tube the noise changes its pitch (or intensity).
When the plate of V5B (6th pin) is disconnected from B+ both termolo and reverb work just fine but they have a very low output volume.

Here are my voltage measurements:

HT 6,12 VAC.

High DC voltages:
point A: 328
point B: 286
point C: 326
point D: 306

V1: 12AX7
pin 1: 195
pin 3: 1,3
pin 6: 197
pin 8: 1,28

V2: 12AT7
pin 1: 136
pin 3: 1,99
pin 6: 148
pin 8: 1,95

V3: 6V6GT
pin 3: 319
pin 8: 23,4

V4: 12AX7
pin 1: 300 - 314
pin 3: 0,19 - 0,8
pin 6: 288 - 317
pin 8: 0,19 - 0,8
Values of the V4 tube vary with changing intensity.

V5: 12AX7
pin 1: 88 - 200 (it changes very quickly)
pin 3: 0,9 - 1,6 (vary with changing speed)
pin 6: 197
pin 8: 0,15 - 1,28 (vary with changing intensity)

I've checked out every connection between all components on the turret board and between all wires going to the tube sockets and power supply and I'm getting a little bit desperat. But I'm willing to chack it out one more time with your help. I appreciate any suggestions. Thank you!