pulling tubes?

[cream123]

i know there's a thread below but i hate to change the topic so i'll start a new one. i have a boogie nomad 100 with 4 tubes and a 50/100watt switch. on the 50 it only uses the inside 2. the one on the inside left is red-plating and i really don't have the cash right now to get it fixed. i was wondering could i just pull though 2 inner tubes out and run it at 100 watts, normally running all the tubes but only the outside 2 in this case. i would think this would work fine but i wasn't sure. it's class a/b push-pull. if i'm not mistaken the inside tubes bias off of each other and so do the outside.

thanks
-marc

[saladin]

Re: pulling tubes?

Try it and see what happens. I've got a Carvin XV-212 which is 100 watts and has a 100/50/25 watt switch. When I tried pulling 2 tubes, regardless of the switch settings, I got a strange ringing sound. I just leave everything as is now on the full power setting.

[Kommerzbassist]

Re: pulling tubes?

Don't forget to half the impendance of the output...

[Binnerscot]

Re: pulling tubes?

If you pull two tubes, you ususally have to set your impedence differently - I forget which way, but it can be looked up in a number of places. If the half power switch shuts down the two outer tubes, just swap the inner and outer tubes, and set the switch to 50 watts until you get replacements....should be safe and keep the amp happy....