I received my BHK preamp today. I did not change any tubes.
I currently have 2 problems:
As already written in another post by other people, the BHK (not the speakers) produces a high frequency whining tone. Since I can change the volume of this tone by turning off other components, I assume this is because of DC or other power pollution. Unfortunately, the P15 is not isolating the outlet (zones) so I think I will try an Isotek Aquarius so that I can isolate the problematic components (TV, AVR) and avoid having any DC noise causing Transformers to hum.
When all inputs are disconnected from the BHK and the BHK is muted, the background noise that the speakers produce while the M700 power amps are on is as expected and barley audible.
Once I unmute the BHK, the background noise gets louder but is still acceptable (Volume on 1)
When I now turn the volume up on the BHP preamp, this background noise gets very loud. Especially at settings where the tubes regulate the volume. For example, at 24 the noise is very high, at 25 it is nearly gone. At louder levels such as 85 the effect worse. This is especially annoying when I use the HT input at level 80. The background noise is no high that I cannot listen to anything then.
Is this normal?
Any recommendation how I can fix this?