Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently May Sat 26, 2018 8:45 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 6 posts ] 
Author Message
 Post subject: Distinguishing between 6U8 and 6GH8a
PostPosted: Jan Sat 27, 2018 8:35 pm 
Member

Joined: Apr Sat 30, 2011 2:14 am
Posts: 605
Location: Mississauga, Ontario
I was sorting through some tubes and came across quite a few that have had the printing wiped clean, I was kind of able to sort out the 12a*7 tubes by comparoson and think i have them sorted correctly but the 6u8 and 6gh8 are virtually identical.
Is there any telltale that would help to distinguish between these two tube types, they look identical to me.
Thanks,
Mauro


Top
 Profile  
 
 Post subject: Re: Distinguishing between 6U8 and 6GH8a
PostPosted: Jan Sat 27, 2018 11:01 pm 
Member
User avatar

Joined: May Wed 01, 2013 10:05 pm
Posts: 1543
Location: Rayleigh, BC, CANADA
I have some as well, they do look identical.

I don't have any data sheets near me right now but I believe the 6U8 has a higher B+ rating.

_________________
Rocco


Top
 Profile  
 
 Post subject: Re: Distinguishing between 6U8 and 6GH8a
PostPosted: Jan Sat 27, 2018 11:03 pm 
Member

Joined: Dec Thu 31, 2009 4:28 pm
Posts: 4505
Location: Medford OR
The one that doesn't work is probably a 6GH8A :lol:

_________________
"I just might turn into smoke, but I feel fine"
http://russoldradios.com/


Top
 Profile  
 
 Post subject: Re: Distinguishing between 6U8 and 6GH8a
PostPosted: Jan Sun 28, 2018 12:54 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 12529
phlogiston wrote:
The one that doesn't work is probably a 6GH8A :lol:


LOL

Now be nice, today it's called being a underachiever...

_________________
Tom


Top
 Profile  
 
 Post subject: Re: Distinguishing between 6U8 and 6GH8a
PostPosted: Jan Sun 28, 2018 8:38 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4951
Location: Rochester NY USA
They're very close, slight difference in transconductance, and interchangeable in most cases. Same with 6BL8, 6EA8, 6LM8, 6LN8, 6KD8, 6GJ8, 6LM8, 6HL8, 6MQ8. The 6GH8 had a higher dissipation rating, though it looks identical inside. May account for short life


Top
 Profile  
 
 Post subject: Re: Distinguishing between 6U8 and 6GH8a
PostPosted: Jan Sun 28, 2018 9:27 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 26370
Location: Detroit, MI USA
You may never be able to tell.

Over the years, various manufacturers have branded tubes in that family with multiple type numbers, and not always the same ones depending on the tube brand.

For all practical purposes unless you are putting them in a color TV that has to have real 6GH8's for any chance of working very long, the others are pretty much interchangeable although in an FM front end, differences in internal capacitance could be an issue.

_________________
Dennis

Experience is what you gain when the results aren't what you were expecting.


Top
 Profile  
 
Post New Topic Post Reply  [ 6 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: upsss and 9 guests



Search for:
Jump to:  
























Privacy Policy :: Powered by phpBB