Help determining age and authenticity of Amperex ECC82 Bugle Boys

GlennDog
GlennDog Posts: 3,121
in Troubleshooting
TIA
Picked up a small batch of 5 tubes this afternoon. The stenciling is a bit faded on some, but that's expected. Seller seems honest/legit, but he's not a professional tube dealer.
He does have a Western Electric tube tester and states all are strong (above the 2000 minimum). They came in plain white boxes with their values of 3100/3400, 3600/3600, 3700/4000, 3200/3600 and 3900/4000

The structure seems identical on the first 4 with a large Halo getter, the 5th getter diameter is quite a bit smaller and labeled a 12AX7A. All 5 have short grey plates

The first 2 are labeled ECC82/12AU7 whereas the 3rd and 4th are labeled 12AU7/ECC82

Near the base of the tube, the first 2 are marked 491 and one has a Gf3 above the 491
The 3rd and 4th have a marking like a triangle that's slanted right followed by 2F2

All state MADE IN HOLLAND and all have white stenciling

Also, the 5th tube (12AU7A) has a stencil # of 637

I won't get a chance to roll these til the weekend, but thoughts on VALUE and authenticity is appreciated . . .

Thanks

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Best Answer

  • heiney9
    heiney9 Posts: 25,198
    edited June 2023 Answer ✓
    Large halo Heerlen Holland tubes are almost always short gray plates (12Axx designation signal tube). They have the Delta Triangle. There was a transition between 1959 thru 1961. 1959 is almost always a large halo, 1960 can be both large and small halo and you might run into an odd 1961 dated large halo. I don't believe any short plate 12Axx tubes were made before 1959 so that's also transitional in that they were moving from long plates to short plates. Most likely for better stability and less susceptible to vibration, etc.

    What you are probably seeing in the "491" tubes is the "4" being a delta triangle with the "9" meaning 1959 manufacture date. Gf3 indicates its a short plate12AU7/ECC82 (3rd build run) I6x top line code is short plate 12AX7/ECC83.

    Above is a crude lesson. Check this out for more info.

    https://tubemaze.info/deciphering-european-tube-date-codes/#more-3636

    Other than the Gf or I6 coding, I'm not sure you can tell the difference between a 12AU and 12AX tube visually. The one with the 12AX7 writing, look for I6x in the top line of code.

    You can stencil any graphics on the bottle, but it's hard to "fake" the etched tube codes. Which is the only way to know what tube it is.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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