It is currently Mon Mar 16, 2020 5:25 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 5 posts ] 
Author Message
Post subject: Why holes in New production 6L6's?
Posted: Wed May 18, 2016 7:39 am
Offline
Amateur
Amateur

Joined: Tue Nov 06, 2007 3:11 pm
Posts: 190
Just curious.
Why do current production 6L6GC's like the JJ, Ruby 6L6GCMSTR's, Russian Svetlana's, Sovteks, and a few others constructed with holes in the plates....vs Old production tubes, not one of which I have found that have anything but solid plates?
Surely the holes are'nt there to vent heat from the cathode?


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Why holes in New production 6L6's?
Posted: Wed May 18, 2016 8:08 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Holes is anode plates of tubes act as access point(s) for grid alignment tools, during the manufacturing process. Original 6L6GC RCA and Sylvania tubes used other methods to align the grids, that did not require access points.

The first tubes that used these access points -- that I recall for output tubes --- is Tungsol. In their 6550 designs (which are higher powered 6L6GC derivatives).

Grid alignment becomes critical, as the tube's output increases --- for safe, dependable service. You see these access points in many transmitter tubes, which can produce thousands of watts.


Top
Profile
Post subject: Re: Why holes in New production 6L6's?
Posted: Wed May 18, 2016 9:58 am
Offline
Amateur
Amateur

Joined: Tue Nov 06, 2007 3:11 pm
Posts: 190
Aha...
It may be that the old tubes, while possibly being superior electrically, have always seemed more microphonic or loose inside as compared to modern tubes.
Maybe this has something to do with needing holes in plates to align grids because of beefed up internal supports nowadays in 6L6's.
That rules out plate holes as being inferior to solid plate construction.


Top
Profile
Post subject: Re: Why holes in New production 6L6's?
Posted: Wed May 18, 2016 11:07 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Actually, the style of holes in the plate may be an indication of quality. EG: The Svetlana V-6550B has small round holes the plates. And are markedly less stable than their successors, the later 1995-2000s SV-6550C. These have rectangular holes and use tools similar to the vintage Tungsol alignment tools. They produce higher safer, wattage. Last much longer than the "B" tubes.

There is no general relationship between solid plate tubes and poor quality. Except for certain specific cases (like above) --- I know of no relationship between styles of holes in plate and quality of tube.

Image

Image


Top
Profile
Post subject: Re: Why holes in New production 6L6's?
Posted: Wed May 18, 2016 11:46 am
Offline
Amateur
Amateur

Joined: Tue Nov 06, 2007 3:11 pm
Posts: 190
That's some good info BMW.
Thanks


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: