It is construction time again. First the basic power supply needs to be tested

OK, no smoke, no blowing fuses. The regulated ±15V, the grid voltage and the anode voltage are measured as expected. After putting it all together the amp even did operate only a big hum did indicate that something was not OK. And indeed: Since I have started just using the basic powersupply (without DC-Heater and Andode-Gyrator) the maximum U_fk of the EL-34 (100Volts) is absotely exceeded.

Adding two 100Ohms "Entbrummer" connected through a suitable voltage divider to the anode voltage did the trick: Enjoy the silence - a very little noise is remaining but it is only noticeable directly in front of the speakers

 Now it is time to burn in verything and collect some listening impressions ... Let's see ...