Impedance Selector Switch vs Multiple Output jacks

[bartolo]

I'm converting a '69 Super Reverb into a head and want options for 2, 4 and 8 ohm speakers. In some of the amp forums guys talk about the problems they've seen with impedance selector switches that result in damaged output transformers.  They recommend using multiple output jacks for long term reliability. I have the 6A, 3 Position rotary switch that was recommended on this forum in 2021. Before I install it I want to make sure that it's the best way to go. If multiple jacks are the better option, that's fine with me.

Another question is what is the recommended wattage and ohms of the open circuit protection resistor (that connects across the tip and sleeve of the output jack) for an impedance selector switch in a Super Reverb?  And, if it's recommended that I go with three output jacks would each jack get it's own resistor that is the same value as the resistor for the selector switch?

Thanks, any guidance here is much appreciated.

[kagliostro]

Power of the safe resistors must be high, use an aluminium version about 1.5 or 2 times the power of the amp, about value usually we see resistors in that position to have a resistence higher than the output they are intended to protect (at least you can use a resistors of the same value, 8ohm impedance, 8ohm resistance)

About selector or multiple jacks I like more multiple jacks but this Isn't mandatory, anyway use good components

With multiple jack don't use safe resistors, they will act as an additional load if the jack Isn',t used and I think you usually don't connect more than a speaker cab at a time

Franco

[stratomaster]

The rotary switch is fine. Just avoid running signal to the amp and flipping the switch simultaneously.

If you're worried about flyback events, add in some 3kV diodes between plate and cathode of each 6L6 like the reissues have.

[bartolo]

Thanks so much for your help!