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Hope someone can help clear something up for me . . .

Posted by JoshT (A) on June 14, 2017 at 22:39:39

I just bought a Rogue Audio RP-5 preamplifier and purchased what I understand to be two matched pairs of NOS Mullard 12au7 tubes to replace the stock JJs. I bought them together through my local audio dealer. The tubes were sourced from Brent Jesse Recording Supply, who I understand is excellent, and I trust my local dealer who has been great over the years. But I am confused by the designations on the boxes of one of the matched pairs.

I have posted two pictures of the same boxes below so you can read each box right-side-up. As you can see, both boxes list the Manufacturer as Mullard and the Tube Type as 12au7. But one lists the Brand as Bugle Boy (which I thought was an Amprex tube?) and the other as something I cannot read but looks like Welscon (?). Also, one box says 1958 LP for Production Type and the other looks like Halo Getter 1958 LP. Unlike the other matched pair, they also have different inspections dates.

The boxes for the other matched pair, which are not pictured, just say Mullard for both Manufacturer and Brand and 1958 LP for both Production types and have the same inspection date.

It seemed to me that maybe there was a mistake in putting these two together before shipping since they seem to be different brands, production types and inspection dates, but my dealer doesn't think so and said Mullard made a lot of 12au7s for different brands. But would they still be considered a matched pair for a preamp? Because he pre-installed them for me (at my request - I have a physical disability), and the preamp is now in a shelf courtesy of my lovely wife, I've not opened the case to inspect the actual tubes yet. Could anyone help explain this for me? Thanks in advance!

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Edits: 06/14/17 06/14/17

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