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Post by riff1006 on Nov 1, 2016 7:16:05 GMT -7
Found the best tube for the PI out of the stash I already had, but am unable to identify it. Can anyone tell me what this is? The white print along the bottom reads 12AX7S and FRC71403. Looks like the logo used to be orange or red, not much left of it. Sorry about the poor quality pics, I used an iphone. Google wasn't any help.
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Post by easyed on Nov 1, 2016 9:34:39 GMT -7
I'm not able to identify a tube just by looking at it but:
My guess is that it was sold as a Groove Tube (orange/red ink and "S" suffix) and is actually a JJ ECC83/12AX7. For Groove Tubes, the suffix usually denotes the country of origin - "S" is for Slovakia and JJ is the only tube manufacturer there. Other GT suffixes are "R" for Russia, "C" for China, and a new one "M" for "Mullard Style"
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Nov 1, 2016 10:31:07 GMT -7
Post by riff1006 on Nov 1, 2016 10:31:07 GMT -7
That's an interesting guess. I thought maybe Amperex w/the old globe logo, but really have no idea. I was hoping the FRC 71403 would turn up on google, but nothing. I was assuming it's a vintage tube, but maybe it isn't.
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Nov 1, 2016 13:23:47 GMT -7
Post by KeithA on Nov 1, 2016 13:23:47 GMT -7
I'm not able to identify a tube just by looking at it but: My guess is that it was sold as a Groove Tube (orange/red ink and "S" suffix) and is actually a JJ ECC83/12AX7. For Groove Tubes, the suffix usually denotes the country of origin - "S" is for Slovakia and JJ is the only tube manufacturer there. Other GT suffixes are "R" for Russia, "C" for China, and a new one "M" for "Mullard Style" This was my first thought as well
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Nov 1, 2016 13:44:32 GMT -7
Post by easyed on Nov 1, 2016 13:44:32 GMT -7
FWIW: The current factory tube compliment for the MAZ 18 Jr is:
V1: JJ ECC83S, V2: JJ 12AX7, V3: JJ ECC81, V4: 12AX7/ECC83, V5: Sovtek 12AX7LPS, V6/7: NOS 6N14N (EL84 – matched pair), V8: Sovtek 5AR4.
I've always been under the impression that ECC83 and 12AX7 were different names for the same thing. Apparently, the Doctor knows better.
At any rate, a JJ 12AX7 is the Doctor's choice.
My MAZ has Svetlana 12AX7's in V1 and V2 an they sound great. These are not NOS, they are current production from the same factory that makes most of New Sensor's tubes. At any rate, I like them.
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Post by perryr on Nov 2, 2016 20:52:22 GMT -7
One of my favorite 12ax7's ever, French made 12AX7S where the S on the end means "special". Often labeled as Dario Miniwatt, or French RT, I believe these were manufactured by La RadioTechnique, Suresnes county plant. They are EZ to spot by the FRS**** code and the flat silver structures that rise above the top mica to support the halo getter. They are typically lower noise by a few db than their Mullard and Amperex cousins, and are on par or even better tone wise.. Depending on what you seek. Mine are a bit more even toned than a Mullard, clear and bright top but not thin, Solid bottom, neutral mids. Closer to an Amperex Bugle Boy, but not quite as sweet. I have 2 Zwrecks, I have a Bugle Boy in V1 of 1 Zwreck and one of these FRS 12ax7s in V1 of the other.
Something Ive noticed about this tube in V1 is that it seems to stay cleaner and clearer and tighter when being hit with fuzzes and overdrives, which may or may not be what one is after. Whatever the case, if it's strong and no issues, its one of the the best 12ax7's on the planet from the glory days of tube production.
Edit: I looked and have 6 of these, the FRS***** code ranges from FRS62*** to FRS67***, so Im guessing they are likely 1962-1967 production. Using that logic, I would guess yours is 1971.
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Post by riff1006 on Nov 3, 2016 6:12:18 GMT -7
Thanks, perryr! Maybe I'll try it in V1 as well then. It really does sound great in the PI. I've seen a lot of tubes but have never seen one like this till now.
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