metal tubes ?

a fine line between stupid and clever

metal tubes ?

Postby GrampaTbird » Wed Dec 03, 2008 2:45 pm

I was running a set of nos 6v6 Sylvania metal tubes
they test as average, but they sure ran hot, a friend brought a
digital thermometer by, one tube ran at 212degrees, the other ran at 180degrees, they sound surprisingly good, but I pulled them and put some glass tubes in they ran below 180degrees. I ran them for several hours with no problems, except maybe the smell of paint on the cans getting very hot.
Just wondering if anyone has experience with these kind of tubes?
GrampaTbird
 
Posts: 4
Joined: Mon Sep 29, 2008 10:30 am

Postby Geek » Wed Dec 03, 2008 5:27 pm

Hi,

I assume you speak in F.?

That's normal for a metal power tube. They are usually rated for 200C. max and 120C. is what my guitar amp 6V6's (GT's though) run at after cranking for a while.

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia

Postby GrampaTbird » Wed Dec 03, 2008 6:24 pm

Hey thanks for the info, I was kinda scared by the hot smell of paint, I'll probably keep them as spares.
GrampaTbird
 
Posts: 4
Joined: Mon Sep 29, 2008 10:30 am

Somethings are not as they seem to be

Postby EWBrown » Thu Dec 04, 2008 6:50 am

FWIW, some of the metal 6V6s are actually a 6AQ5 hidden inside, along with a 9 pin to octal adapter base. In most cases, this would work fine, but in hard service like a guitar amp, they wouldn't hold up as well as "real" 6V6s or 6VGTs.

/ed B
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Postby soundbrigade » Thu Dec 04, 2008 10:59 am

I have built the MAD Stealth using 12A6, 12SJ7 and 12SC7, all full metal jacket, and YES the tubes run HOT. I have a smallish ECL82-SE-amp with a 5Z4-metal recifier and I use that tube to shrink heat shrink tubes ...

However I have no idea how hot the tubes run and I haven't made any comparison with GT-tubes.
Magnus

"It is always more difficult to fight against faith than against knowledge."
User avatar
soundbrigade
KT88
 
Posts: 1759
Joined: Mon Jan 28, 2008 4:57 am
Location: Little Paris, Sweden

hot stuff... but without the pretty glow...

Postby EWBrown » Thu Dec 04, 2008 12:22 pm

The metal tubes will be significantly hotter just because metal conducts heat more effectively than does glass, as well as their envelope diameter is smaller with metal tubes as opposed to tubes with glass bulbs.

The metal tubes would hold up better on board of a B-17 or Sherman tank, than would their more delicate glass counterparts. Yellow_Light_Colorz_PDT_11

A metal 6L6 is not upwardly compatible to 6L6GC, as the total plate and G2 dissipation is significantly lower. 19W vs 30W.

/ed B
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !


Return to guitar amps

Who is online

Users browsing this forum: Google [Bot] and 3 guests