Resistor values for neg. feedback

[Fummelfinger]

Hi everyone. I‘m in the process of converting a 2x6L6 combo (Roland Bolt) that into a Dumble clone (hopefully). Now I need some advice on what values I should use for neg. feedback since the OT only has one 8 ohm tap but the diagrams I‘ve seen so far show the signal taken from a 4 ohm tap. Should I still try to use the 4K7/390R combination or would the values have to be changed for good results? (The presence control is 2.2K)

[martin manning]

The 8-ohm tap will have 1.4x the voltage, so a good place to start would be increase the 4k7 feedback resistor to 6k2 or 6k8.