Shiva EL34 reverb silver back noise - is this normal

[wiorys]

Hi

I've just bought Shiva, do old pre-2005 models have some noise even if nothing is plugged in?

1) No cable plugged in (besides speaker cable )
2) knobs set to 0 (also setting them to different settings make little difference)
3) reverb/channels do not make any difference
4) I've replaced preamp tubes - same issue.
5) Replaced power amp tubes - same issue.
6) Noise character depends on fan setting.
7) There is no noise in standby mode.
8) Checked bias, it is quite low ~18ma though I've used newer Svetlana tubes biased to 30mA and had the same issue.

I am talking about noise coming out of speakers, not about the mechanical noise created by fan.

Here's how it sounds:
https://www.youtube.com/watch?v=JzTOdO3 ... e=youtu.be

I've owned some amps, including Mesa Mark IVa with a fan (larger...and quieter) and none did this.
Only Peavey has some white noise even if guitar is not plugged in, though it's more typical "nice" sounding white noise.

I wonder if that's normal or something is wrong with this amp. its not that loud, you can't hear it when you play the guitar but when you stop it is hearable.

Fan cables seem to be connected to:
- power amp socket metal base/ground
- fan switch (some condenser is here, also some resistor).

 

[lkft]

I have a 2004 Shiva and mine did that too and it was the fan blades hitting the fan housing, I guess they tend to warp. I had Bogner send me another fan and replaced it and it's been good to go ever since.