Grid - Screen Alignment (X-Rays)

kenpeter · 30th September 2008, 12:58 AM

I recently promised someone I'd xray the Chinese 6L6CGR I had.
Don't remember now which thread? Might as well start another...
There are no holes "for screen alignment" in plate of this tube.
Don't know if that is really what typical beam power plate holes
are for, or something else?

kenpeter · 30th September 2008, 01:00 AM

Pic 2

kenpeter · 30th September 2008, 01:02 AM

Pic 3

This tube is just slightly too big to fit all in one Xray image.
But I have one coming that tries to cover most of it.

kenpeter · 30th September 2008, 01:05 AM

Mind you, both getters were in the bottom. These wings are for G1.

kenpeter · 30th September 2008, 01:07 AM

Extreme closeup of alignment (or mis-alignment?) near the center.
I have no reason to think there is anything especially wrong here.

DigitalJunkie · 30th September 2008, 01:43 AM

Wow,Cool pics!

Sch3mat1c · 30th September 2008, 02:28 AM

On the right side of the third image, it looks like parallax effect reaches a minimum and the grid-screen offset is about 20% of the winding pitch. Could probably be better...

Thanks for the x-rays!

Tim

Sch3mat1c · 30th September 2008, 03:01 AM

Bah, I was just about to edit then it said it timed out...

Edit: here's the image, brightened up a bit (for analyzing relative density, refer to the original) and with a scale marker (based on the bulb being about 1.5" across). Evidently the grid pitch is about 14 TPI, so the misalignment is around 0.014".

Tim

Sch3mat1c · 30th September 2008, 05:07 AM

*cough*

kenpeter · 30th September 2008, 08:42 AM

The total diameter across the entire glass envelope,
which also happens to be the same diameter as the
octal base, is only 1.3 inches. Rather small for a 6L6.

Dunno what breed of monster you thought this was?
I think you might have diameter mixed up with radius.
There is simply no way this tube is 3 inches across...

Its probably too late to edit your post now, but you
seem to be hosting the picture elsewhere. I would
assume you still have access to edit the scale?

How does this affect your calculation regarding the
pitch of the grids?

30th September 2008, 02:28 AM	#7
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	On the right side of the third image, it looks like parallax effect reaches a minimum and the grid-screen offset is about 20% of the winding pitch. Could probably be better... Thanks for the x-rays! Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

30th September 2008, 03:01 AM	#8
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Bah, I was just about to edit then it said it timed out... Edit: here's the image, brightened up a bit (for analyzing relative density, refer to the original) and with a scale marker (based on the bulb being about 1.5" across). Evidently the grid pitch is about 14 TPI, so the misalignment is around 0.014". Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

30th September 2008, 05:07 AM	#9
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	cough __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

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30th September 2008, 01:43 AM	#6
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	Wow,Cool pics!

30th September 2008, 08:42 AM	#10
kenpeter diyAudio Member Join Date: Nov 2007 Location: Dallas	The total diameter across the entire glass envelope, which also happens to be the same diameter as the octal base, is only 1.3 inches. Rather small for a 6L6. Dunno what breed of monster you thought this was? I think you might have diameter mixed up with radius. There is simply no way this tube is 3 inches across... Its probably too late to edit your post now, but you seem to be hosting the picture elsewhere. I would assume you still have access to edit the scale? How does this affect your calculation regarding the pitch of the grids?

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