How to spot Chinese vs UK KT66's

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VelvetGeorge
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How to spot Chinese vs UK KT66's

Post by VelvetGeorge » 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
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Post by VelvetGeorge » Tue Apr 10, 2007 1:41 pm

Here are some pics to help identify the differences. In each the GEC is on the left and the Shuguang in on the right.

george
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Post by darrell » Sun Apr 15, 2007 11:14 am

The label Is the first thing every one looks at . I agree that you should not go by just that, But it caught my eye first and i noticed that it was high on the glass and had a hard angle to it. Also the square hole in the plates are different size's the real deal has a bigger square hole then the shug's.
Just rying to help point out some of the more obvious because they wont allway's let you see a upclose pic of the tubes.. I hope this helps I know doing a side by side here has helped me point out some things i never noted before.
Below is the fake GEC/ china
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Post by pjbottoms » Sat Feb 02, 2008 10:19 pm

I have heard that the gray glass versions are always real cause there are no new manufacturers making a grayed glass kt66. Is that true ? Are GEC and Genalex the same thing ?

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Post by frenchie » Tue Apr 01, 2008 6:11 am

a have a quarte of 11th gen shugs ..and i tell you ..they also are reducing the thikness of the getters to look more gec -ish .. beware guys ...now it become closer and closer :shock:

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Re: How to spot Chinese vs UK KT66's

Post by skurtix » Thu Mar 04, 2010 5:04 am

Maybe if Shuguang keeps trying to mimic the resemblance of the old GEC tube it will start sounding better and better :lol:

What about this tube? I've heard these are relabeled Shuguang's

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Re: How to spot Chinese vs UK KT66's

Post by novosibir » Sun Apr 04, 2010 4:53 pm

Yes!

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Re: How to spot Chinese vs UK KT66's

Post by worldoftone » Thu Sep 02, 2010 10:27 am

Good Stuff!

- WOT
I smell tubes.

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Re: How to spot Chinese vs UK KT66's

Post by 68Plexi50 » Sat Jun 11, 2011 11:15 am

How do these look ? Weird looking getter

Test Results TEST DATA
AVO 160 Tester
Vf=6.3 v ,Vp=250 v ,Vg2=250 v & Ip=65.0 mA .

TEST RESULT
Tube 8 gm=5.25 @ - 19.4 v. bias .
Tube 10 gm=5.28 @ - 22.4 v. bias .

Not being technical ..... does this mean they test Good ??

:toast:
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