It is currently Mon Mar 16, 2020 2:20 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 7 posts ] 
Author Message
Post subject: What tubes are those ? (amp tubes of a Fender 140)
Posted: Sat Sep 06, 2014 6:15 am
Offline
Hobbyist
Hobbyist

Joined: Wed Aug 27, 2014 1:53 pm
Posts: 15
Hi,

I found those amp tubes in a Fender 140. According to the schematics they are supposed to be 6L6GC. Unfortunately, there's nothing printed on them whatsoever.

So, does anyone know what those tubes might be and where they might come from?

http://www.emerald-green.de/images/fender140_amp_tube_005.jpg
http://www.emerald-green.de/images/fender140_amp_tube_006.jpg
http://www.emerald-green.de/images/fender140_amp_tube_007.jpg

fender140_amp_tube_008.jpg
fender140_amp_tube_009.jpg
fender140_amp_tube_010.jpg
(for the last three please add the above url infront of the file name)

Any hints very much appreciated. Thanks a lot.


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: What tubes are those ? (amp tubes of a Fender 140)
Posted: Sun Sep 28, 2014 11:32 am
Offline
Hobbyist
Hobbyist

Joined: Sat Aug 23, 2014 12:11 pm
Posts: 13
It looks like a kt66 to me, also the next one up is kt88 at 50 watts each.

...andy


Top
Profile
Post subject: Re: What tubes are those ? (amp tubes of a Fender 140)
Posted: Sun Sep 28, 2014 12:08 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
These are 6L6G or 6L6GA coke bottles. Rated at max of 19 watts per tube.

http://tubeworldexpress.com/search?q=6L6G


Top
Profile
Post subject: Re: What tubes are those ? (amp tubes of a Fender 140)
Posted: Sun Sep 28, 2014 3:42 pm
Offline
Amateur
Amateur

Joined: Thu Apr 11, 2013 2:55 pm
Posts: 183
I've got a duet of those 6L6G's from an organ and wondered about using them in a deville.....I'm surprised they were in an amp calling for 6L6GC's. Wonder if they would hold up at the high plate voltage?


Top
Profile
Post subject: Re: What tubes are those ? (amp tubes of a Fender 140)
Posted: Sun Sep 28, 2014 6:02 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
The 6L6G and 6L6GA may not work well in an amp designed for 6L6GC. You can bias the amp so the tubes run at 13 watts per tube (70% of max), but the high plate voltage may make them vulnerable to runaway. Dropping the screen voltage, well below 10VDC of anode, may help stability.

Really, Fender didn't "solve" this issue until they started using 5881 tubes.


Top
Profile
Post subject: Re: What tubes are those ? (amp tubes of a Fender 140)
Posted: Mon Sep 29, 2014 1:20 am
Offline
Hobbyist
Hobbyist

Joined: Wed Aug 27, 2014 1:53 pm
Posts: 15
Thanks a lot for your replies everybody.

The Fender 140 is rated around 130 Watts and has 4 of those tubes (2 pairs parallel).
Unfortunately, I'm not an expert reading schematics (still working on it).

This is the original schematics of the amp:
http://www.emerald-green.de/images/fender-140-schem.jpg

If the tubes I found in there are 6L6G/GA, would I be okay leaving them in there or should
I rather replace them with the 6L6GC that are supposed to be in there?


Any suggestions?


Top
Profile
Post subject: Re: What tubes are those ? (amp tubes of a Fender 140)
Posted: Mon Sep 29, 2014 1:24 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Check the idle bias of the tubes in the amp. I would not recommend anything over 14 watts per tube (~70% of max). If you are going for new tubes, get 6L6GC. I recommend Tungsol 6L6GC-STR.

Good luck! :D


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 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: