6BG6-GA - Page 3

scott17 · 6th January 2013, 04:43 AM

Quote:

Originally Posted by scott17

Does anyone know if the large grey plate 6BG6GA were ever made with side getters?

I guess they did make the large plate with side getters. I've been running mine at 430V, 30W, in UL mode, no red plating.

scott17 · 11th January 2013, 08:18 PM

I purchased a few of the "super" 6BG6GA. Here is a photo of the "super" version (on the left) next to the version I have. The plates look identical. Can someone tell me what the 2 fins on top of the mica insulator are for?

I am now running my version in SE UL mode at 465V on the plate, 455V on the screen, at 73.4mA. About 30W dissipation. So far, so good.

vinylkid58 · 10:23 PM

Quote:

Originally Posted by scott17

Can someone tell me what the 2 fins on top of the mica insulator are for?

Possibly to radiate heat away from the grid posts?

What sort of a driver config. are you using for this project? Thx.

jeff

Miles Prower · 12th January 2013, 02:26 AM

Quote:

Originally Posted by scott17

I purchased a few of the "super" 6BG6GA. Here is a photo of the "super" version (on the left) next to the version I have. The plates look identical. Can someone tell me what the 2 fins on top of the mica insulator are for?

They look like screen grid radiators.

scott17 · 12th January 2013, 03:11 AM

A 6SN7 with 355V through a 28K plate resistor. A green and white LED in series on the cathode at 5.25V for 6.3mA current. I will post a schematic when I get to work in the morning.

Quote:

Originally Posted by vinylkid58

Possibly to radiate heat away from the grid posts?

What sort of a driver config. are you using for this project? Thx.

jeff

scott17 · 12th January 2013, 03:14 AM

I looked that up. That looks exactly like what they are. Thanks.

Quote:

Originally Posted by Miles Prower

They look like screen grid radiators.

scott17 · 12:23 AM

Very simplistic circuit.

I had a PT with a 12.6 CT & 10V CT secondaries, so I wanted to make use of it. I know the 5AR4s are overkill in this application. I will ultimately use 5V4GAs as the rectifiers, I just don't have them yet.

Output measured at about 7.5W RMS

Scott

prairieboy · 2nd March 2013, 02:21 PM

Scott, did you do any 'in circuit' comparisons between the 'super' 6BG6GA you purchased versus the side getter version you already had? I was checking through a box of tubes from an old Ebay purchase this morning, and found I've got 12 of the 6BG6GA that are identical to your original ones (Sylvania, grey plates, side getters, screen grid radiators) so I'm curious if you concluded that they 'are' the super 6BG6GAs?

scott17 · 2nd March 2013, 03:56 PM

Both tubes run at the same parameters in my circuit. Comparing the plates of the two they are identical even down to the mica insulators. Only difference is apparently the side getter and screen radiators.

In case you didn't see the photo linked in post #8, you can definitely see the difference there.

Quote:

Originally Posted by prairieboy

Scott, did you do any 'in circuit' comparisons between the 'super' 6BG6GA you purchased versus the side getter version you already had? I was checking through a box of tubes from an old Ebay purchase this morning, and found I've got 12 of the 6BG6GA that are identical to your original ones (Sylvania, grey plates, side getters, screen grid radiators) so I'm curious if you concluded that they 'are' the super 6BG6GAs?

prairieboy · 3rd March 2013, 02:00 AM

Thanks for the response, Scott.
BTW, I did see the photo in #8. The 6BG6GAs I have look like the left hand image, with the side getters.
So, from what you're saying I may infer that the top getter 'super' 6BG6GAs are functionally the same as the side getter, big, gray, plate 6BG6GAs? If so, good news.

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2nd March 2013, 02:21 PM	#28
prairieboy diyAudio Member Join Date: Nov 2010	Scott, did you do any 'in circuit' comparisons between the 'super' 6BG6GA you purchased versus the side getter version you already had? I was checking through a box of tubes from an old Ebay purchase this morning, and found I've got 12 of the 6BG6GA that are identical to your original ones (Sylvania, grey plates, side getters, screen grid radiators) so I'm curious if you concluded that they 'are' the super 6BG6GAs?

3rd March 2013, 02:00 AM	#30
prairieboy diyAudio Member Join Date: Nov 2010	Thanks for the response, Scott. BTW, I did see the photo in #8. The 6BG6GAs I have look like the left hand image, with the side getters. So, from what you're saying I may infer that the top getter 'super' 6BG6GAs are functionally the same as the side getter, big, gray, plate 6BG6GAs? If so, good news.