Hello I try explain my problem, but my english is too bad.
I have a K4040, when I power on the product, after warm up I ear a sound in two channels “BRRRRRRRRRR” and I don´t ear the music.
How I can do for solution this problem?
Short the inputs of the amp.
If you still hear this sound after warm-up, the problem is most likely related to an assembly problem.
If not, it is related to the external wiring or the source.
If I quit the valveV11 (ECC82) the noise disapear.
And if I don´t connect font into the input, the noise is continuous.
Hello I solution my problem, but I have a new question, when I ajust the bias, in the manual read i ajust to two leds with red color, but I ajust two this red leds or to two green leds?