socialparasite said:
I have heard JJ's are 1 of the best and give you a darker sound? I am looking for the best metal sounding tubes on the market. Will my dual rectifier blow up if i dont use mesa tubes? Will it overheat or mess up? I like mesa but i think its a load of crap that we are suppose to only use mesa tubes :x I read in other post but no one gives a simple yes or no wether or not it will mess up your amp
Yes, the JJ's are a bit darker sounding to a certain extent, but it depends on which JJ's you're talking about. The 6L6GC's can be fatter sounding, but they're typically not all that fat in a Recto while running them in the amp's stock bias. The JJ 6L6GC's are still real aggressive and the JJ EL34's and E34L's are as well.
No, you will not blow your amp up if you use JJ tubes. If you use JJ 6L6GC's, the tubes will actually run cooler than those that Mesa sells. JJ 6L6GC's typically do not draw a lot of natural plate current. So, you're not going to be overheating any way you look at it. As long as you don't use hotter tubes, you should be fine.
As far as looking at it from a technical standpoint, you will be fine there as well. Mesa Rectos are set up to run 6L6GC's. The Impendence isn't quite correct to run EL34's, but it's safe and close enough. You just aren't able to juice out the full EL34 type of tone, but like I said earlier, it's close enough and you have the switch on the back of the amp to make this change.
Then you can look at the heater current issues. If you can run EL34's in the amp, you can run any 6L6GC's. JJ's heater current draw for their 6L6GC is probably right at .9 amps and their EL34 and E34L is probably right at 1.4 amps. Both of those figures are in spec and if the power transformer couldn't handle that, they wouldn't advise running EL34's in the amp.
The only difference is that the plate voltage will hop up a little bit if you're using JJ 6L6GC's in your amp due to their lower natural plate current draw. The cathode current (aka bias current) will be lower and that's what causes this. It's not a big deal at all and the amp should be fine.
The plate voltage of any amp will vary at any given time due to the current coming in from the wall. If you fire your amp up at home and then take it to your practice space or a friend's house, you can expect different plate voltages from the amplifier due to the differences and that will yield different cathode current (bias current) readings.
So, that's the long winded response. The answer to your question is no. Just request tubes that will be safe to run in your amp and you will be fine. Make sure they're not too hot.
Dale
