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Post by bhayn007 on Jan 26, 2013 14:09:37 GMT -7
This has probably been answered before, but how are the power tubes paired? I looked through past threads and couldn't find the answer. If I was to swap a pair would I change the inner pair and outer pair together or the two next to each other?
Thanks
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Post by headshrinker (Marc) on Jan 26, 2013 19:01:45 GMT -7
Ideally they all should be matched. I am pretty pretty sure they are split left two and right two so if you only change two you would do outside two or inside two so the left and right have the same combination. If they are not all four matched but are matched two and two but each pair is different from the other you might get some hum as the self-biasing might have a bit of a problem. At least that's how I understand it. The one thing I know you can not do is pull two of the tubes like you can on a fixed bias 4 tube amp like a twin to get less wattage and volume. That's a big no no.
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Post by bhayn007 on Jan 27, 2013 17:16:58 GMT -7
Thanks for your help. I was mostly wondering for a quick replacement during a gig. I bought a matched pair of ruby tubes to keep on me in case something went out. I would purchase a matched quad for long term replacement, but was just wondering how to fix the problem on the fly if the need arose. Would swapping out just one or a pair do the trick short term? Or, do people carry matched quads to shows?
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Post by headshrinker (Marc) on Jan 27, 2013 18:23:10 GMT -7
I think most people with a 4 tube amp carry a quad. Especially when doing things on the fly. The problem is usually you can not tell which tube is giving you the problem by looking. The tube will look the same (be glowing, the same color etc.)as the other tubes. It's just not doing what it is supposed to correctly. You need a tube tester to test the tube and sometimes they don't show the problem. I also think many folks carry a backup amp for even faster fixes. I carry a backup amp and a new set of tubes for both but I'm a bit ocd about it.
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Post by bryan0418 on Jan 28, 2013 9:56:28 GMT -7
I would replace them as a quad only. Also be sure to only use 7189s because of the higher voltages. Regular el84s won't work.
I have one of those electro harmonix 22 caliber power amps I bring to my shows. It will give you 22 watts of power should your main amp fail. It is the size of a pedal and fits right in my bag. Way better than bringing another amp.
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Post by bhayn007 on Jan 28, 2013 18:47:44 GMT -7
Thanks, looks like I'm going to take these rubies back and order a quad.
I like the looks of that 22 caliber. How does it sound in real life? Loud enough?
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Post by bryan0418 on Jan 29, 2013 7:12:15 GMT -7
It sounds pretty good. Of course it wont have as much depth as a tube driven z but it will give you clean headroom till about noon on the volume and then i5 breaks up nicely after that. It is plenty loud for most applications. If you play very large stages then you may want to look at the bigger brother, the EH 44 Magnum. Be advised the Z Wreck 2x12 with the blue/Gold is a 30 watt cab due to the Blues 15 watt rating. It is a nice peace of mind device.
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Post by M Fowler on Feb 4, 2013 23:54:25 GMT -7
Use quad a set when replacing tubes. I use JJ EL84's. The 7189 are good tubes as well. Plate voltage is not a problem.
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