They seem to be a 9V Zenner and a 15V Zenner.... just replace them. They are most likely 500mW type, but you could use 1W type no problem.
I ordered diodes. I forgot to say that the sound in the amplifier appears only after 10 seconds. How does the muting system work here?
Maybe it's muting system make white noise?
Maybe it's muting system make white noise?