How to spot Chinese vs UK KT66's
Posted: Mon Apr 09, 2007 10:38 am
Thanks to a close call recently, I'm learning to spot the difference between the Shoguang and real GEC KT66's.
The best indicator to differ Chinese from the GEC is:
- look through the big windows in the plates
- there you can see the beam forming plates
- a triangle form with the corner facing you is GEC
- a square form is Shuguang
Look at all the labels. There in the same spot compared to the other tubes and they are slanted / waht would be the odds of this happeing?
I agree with Larry, the internal structure visible through the plates is a good indicator, if you can access that view. Moreover, even if you can't and can only see the top of the tube, the differences in the fabrication of the beam formers leads to that funky looking silver plated tab poking vertically through the top mica on the Shuguang, centered over the "windows" in the plates, and this will never be present on a real British KT66 (which instead have a pair of small grey tabs bent flat to the mica or close to, off the sides not in the middle). The tops of genuine M-OV KT66s do vary depending on vintage (as does the orientation of the plates to the guide key), but none of them have those centered vertical silver tabs. Generally, from the side view facing the plate "windows", on a real GEC KT66 the only visible pieces protruding up through the top mica and pointing vertically are rod shaped, circular or "flattened circular" in cross section, not wider "tabs".
But you usually don't even have to look that close up there, the "flat washer" getter rings on the Chinese are a dead giveaway as well, even in lousy photos. All GEC KT66s have dual halos at the bottom after the very end of 1964 or so, but they look quite different.
OTOH, "GEC" decals on genuine pieces can be angled and all over the place, I wouldn't especially look to that in preference to the constructional details. Plus of course the genuine M-OV valves can have many different labels and brands.
More to come, I'll be updating.
george
The best indicator to differ Chinese from the GEC is:
- look through the big windows in the plates
- there you can see the beam forming plates
- a triangle form with the corner facing you is GEC
- a square form is Shuguang
Look at all the labels. There in the same spot compared to the other tubes and they are slanted / waht would be the odds of this happeing?
I agree with Larry, the internal structure visible through the plates is a good indicator, if you can access that view. Moreover, even if you can't and can only see the top of the tube, the differences in the fabrication of the beam formers leads to that funky looking silver plated tab poking vertically through the top mica on the Shuguang, centered over the "windows" in the plates, and this will never be present on a real British KT66 (which instead have a pair of small grey tabs bent flat to the mica or close to, off the sides not in the middle). The tops of genuine M-OV KT66s do vary depending on vintage (as does the orientation of the plates to the guide key), but none of them have those centered vertical silver tabs. Generally, from the side view facing the plate "windows", on a real GEC KT66 the only visible pieces protruding up through the top mica and pointing vertically are rod shaped, circular or "flattened circular" in cross section, not wider "tabs".
But you usually don't even have to look that close up there, the "flat washer" getter rings on the Chinese are a dead giveaway as well, even in lousy photos. All GEC KT66s have dual halos at the bottom after the very end of 1964 or so, but they look quite different.
OTOH, "GEC" decals on genuine pieces can be angled and all over the place, I wouldn't especially look to that in preference to the constructional details. Plus of course the genuine M-OV valves can have many different labels and brands.
More to come, I'll be updating.
george
