Pulling tubes in 150 watt amp

Hi,
I have a mesa stiletto trident stage 2 and most of the time I'm running it in 50 watt mode. Can I pull the 4 inside tubes and just keep the 2 outside 50 watt ones running so I'm not wasting the life of the other just on idle????

Thanks

I don't think it will significantly affect the tube life to keep them in while idle. Tube life is inversely proportional to how hard you run them.

The tubes are required to be left in the amp to keep the Output Transformer's impedence in balance. If you pull those tubes you would need to offset your speaker load by 2/3 to keep the balance, for example a 12 ohm cab on the 4 ohm OT tap would be a correct match.

Just leave them in. The only thing "on" with the unused tubes is the heaters, which were designed to outlive the tubes anyway. If it really bothers you just rotate the pairs every month or so.

Dom

Thanks a bunch !! Takes a load off my mind to know I'm not just burning them out on idle. I'll start to rotate them through the 50 watt setting soon.

It's go to know about the impedence setting to I thought it might have been alright at 1/2 but 2/3 is a bit weird. Thanks again.