[Zealot261]

I just have a quick question regarding the ASL MG Head. Will it hurt the amplifier if the headphones are unplugged will it is still on? I have no idea what the circuit topology is like in these guys so I wont try to guess. I know in buffered solid state amps its not good to unplug the headphones, that whole resistance goes to 0 current to infinity thing(Ohm's Law).

Any answer or pointer in a direction to find an answer would be much appreciated. Thanks in advance.

 

[oldears]

I can't give you a theoretical answer. However, I do own a MG head--and have for several years. In order to tryout/evaluate headphones I have unplugged headphones many, many (many!) times with the amp turned on. Just like a Timex watch, "It takes a lickin and keeps on tickin". I always turn the volume all the way down first, however.

I have read several times that you shouldn't unplug the headphones without turning the unit off first. My practical experience has been that it hasn't hurt the unit. I personally think that repeated on/off is bad for the tubes.

 

[Hirsch]

The part most in danger is the output transformer. If your unit is one with the OTL switch, going OTL takes the transformer out of the circuit, and minimizes risk of damage. Unless an tube amp is specifically designed to provide some sort of dummy load to protect the transformer, it's a bad idea to run such an amp without a load. Short periods (switching headphones) are less risky than just leaving an amp on. Replacing tubes is quick and easy. Replacing an output transformer is not.

 

[JaZZ]

Without any signal or with volume turned down, there should be no danger whatsoever.