#1
what does the b stand for? ive noticed there are other tubes marked 12ax7a as well.....anyone know what these designations stand for?
#2
It probably just denotes a later version of the tube. For example, old Philips JAN military 12ax7s were labeled 12ax7wa, wb, or wc depending on when they were made, wa being the oldest version.
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#3
Quote by arteestic1
what does the b stand for? ive noticed there are other tubes marked 12ax7a as well.....anyone know what these designations stand for?


Well the B means blue, as in the tube glows blue instead of the normal orangish colour.

Now the A means awesome because these increase the crystal lettuce produced by your amp, thus making more T0AnZ availble for your finger tips.

But as a 12ax7a grows older it looses its ability to aid in the production of crystal lettuce so they get sad amd start glowing blue. Amd thats where 12ax7b tubes come from
#4
And if you combine the two, you get a fantastic balance of haunting mids with fragile harmonics.
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#5
What brand of tube is it?
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#6
Quote by Cathbard
What brand of tube is it?


its hard to say, all i can find is "12AX7B" and "CHINA" right below it in white lettering. no other markings on the tube that i can see.

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Last edited by arteestic1 at Mar 3, 2012,
#7
Ah ok, I have some of those. I'm pretty sure they're made in the Shuguang factory in China. Like I said before, I think the b designation just denotes a later version of that tube from that factory.
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#8
Quote by BCKRedBaron
Ah ok, I have some of those. I'm pretty sure they're made in the Shuguang factory in China. Like I said before, I think the b designation just denotes a later version of that tube from that factory.


ok, just curious. i have the other 3 Engl ecc83fq's to swap them out with. anyone have a tube they'd recommend rolling with. ive seen tung sol mentioned alot on some other threads, im new at this and really dont know where to start as far as brands go. everyone seems to like jj's though. are these engl's any good, comparatively?
#9
I'm not sure what tubes ENGL relabels, so I can't say how they are. JJs are the best new tubes for the money. Tung-Sol are good, but supposedly they fail in cathode follower positions. I have no clue whether your amp has one of those or not. JJ are better anyway; I'd start with them.
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#11
I think it means "balanced" I have 2 12ax7's that have that and they are a balanced tube.
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#12
ok, so if cash isnt an issue, would it be safe to say, jj's for the preamp and winged c power tubes are the way to go?
#14
Weeellll, if cash isn't an issue AT ALL, I'd say go NOS or used old stock. But if you really don't wanna spend an arm and a leg, JJ and Winged C will do you just fine.
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#15
OK, they are Shuguangs. A, B, and C denote 7th, 8th and 9th generation respectively.
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#17
Quote by Cathbard
OK, they are Shuguangs. A, B, and C denote 7th, 8th and 9th generation respectively.


ok, gotcha. thanks for all the help everyone!
#18
PS: I noticed you were holding the tube with a rag. You only need to do that if they are hot. If you are doing it because of the urban legend about sweat causing hot spots and causing the glass to crack, don't bother.
The glass on those is tough and can handle far more heat than they can ever generate. I've seen tubes covered in what looked like a pack of cheetos and I'm yet to see a tube's glass fail unless somebody hit it with something hard.
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#19
Quote by Ippon
9th gen Shuguangs are the preferred preamps for high gain amps like the Uberschalls and Twin Jets.


i have an uberschall, blue revision. so the chinese tubes sounds best in this amp? or just the shuguangs? should i skip the JJ's then? was thinking of getting the jj's and trying a ruby in v1 due to some advice from a friend...but id probably end up trying it out all over to see what sounds best to me. but if these tubes that were in there are the ones to go with, ill try and find some more and roll with a few different types until i find a combo i like. any suggestions?
#20
The Ruby will probably be a Shuguang too.

I like JJ's but on some amps it's worth experimenting with different tubes in V1 to add a few more highs. A proper British Mullard could be a good choice for V1 and JJ's everywhere else.
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#21
Quote by Cathbard
The Ruby will probably be a Shuguang too.

I like JJ's but on some amps it's worth experimenting with different tubes in V1 to add a few more highs. A proper British Mullard could be a good choice for V1 and JJ's everywhere else.



ok good deal. well, i guess ill wait until payday an see if i can scoop those up. will report back once i do some experimenting. thanks again!
#22
Gen 9 Shuguangs would still be a good choice. See what you can get for what. Get a few of each and just experiment. No two valves sound identical, you just have to try different combinations.
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#24
decided to do somer playing around with the engl tubes and the shuguang 8th gen. the shugu's sure seem brighter and tighter on the low end while the engls, wherever they are from are really floppy down low. and with the amount of bass this amp produces, i found having a shuguang in v1 and v5 made a def improvement. it still had alot of low end to spare but it wasnt as spongy, the rest i can dial in with my eq.'s thinking about using these, the engl's and maybe buying a couple each of jj's, ruby's, mullards to play around with. i dont want to get into mixing 5 brands in my preamp, but just to compare.
#25
Mix them up as much as you like. There's no reason that you couldn't have a different brand tube in every position. Whatever works best.
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Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
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Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#26
It could have something to do with gain, or possibly the heater configuration for the pins in the amp.
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