MarshallForum.com
 
Go Back   MarshallForum.com > The Amps > The Workbench
LIKE MarshallForum on Facebook FOLLOW MarshallForum on Twitter
  
Reply
LinkBack Thread Tools Display Modes
Unread 03-28-2010, 08:05 PM   #1 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: Massena, NY
Posts: 662
12AX7 and 12AX7A Whats the difference

What is the A for in the suffix. Can I run both these in my 2204
__________________
Bill Griffith Paramedic/Firefighter/Diver
Current Gear:
Left hand guitars:
2009 Gibson SG Standard

Amp:
1982 JCM 2204
1960A Cab
Marshall MG10


Good transaction members: timgman, beamer23, Joey Voltage(for amp service A+++), RJohns, JCarno, Chuckharmonjr, MM54, Martystrat54, ant_riv

ALL WORK DONE ON MY AMPS BITCHINGLY DONE BY JOEY VOLTAGE--ROCK ON
Paramedic006 is offline   Reply With Quote
Alt Today
Marshall Amps

Beitrag Sponsored Links

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on MarshallForum.com
   
Unread 03-28-2010, 08:26 PM   #2 (permalink)
Super Moderator
 
MartyStrat54's Avatar
 
Join Date: Feb 2009
Location: Now in Muskogee, by Tulsa
Posts: 25,981
Send a message via Yahoo to MartyStrat54
Re: 12AX7 and 12AX7A Whats the difference

12AX7: the original version of this tube, released in 1947. This can only be used in parallel filament circuits. This is not a big deal as virtually all audio equipment is of a parallel filament design. In other words, these will work fine in a Marshall.

12AX7A: This version can be used in series or parallel filament circuits. These usually date to the 1960s and have gray or black plates. Vintage versions of these are about the most sought after tubes of any type today. Sometimes, 12AX7A tubes made for the US Military are labeled 12AX7WA. DO NOT confuse these with current production Sovtek or Chinese crap with the suffix WX, WB, or WC! These are not military tubes and are not NOS tubes at all.

Also, as tube manufacturing became refined, the 12AX7A became much quieter. So much in fact that a lot of 12AX7A's were labeled 7025's (a very quiet version of the 12AX7).

So the bottom line is that you can use either of these tubes in your Marshall amp. It's just that an NOS 12AX7A tube is considered to be premium over the 12AX7.
__________________


MartyStrat54 is offline   Reply With Quote
Unread 03-28-2010, 08:48 PM   #3 (permalink)
Senior Member
 
MajorNut1967's Avatar
 
Join Date: Jul 2009
Posts: 3,899
Re: 12AX7 and 12AX7A Whats the difference

Oh the "A" in 12AX7A stands for Alpha, because the barium they use on the getters is from Alpha Centauri. And it make the tube have a better magnetic flux.


MajorNut1967 is offline   Reply With Quote
Unread 03-28-2010, 09:24 PM   #4 (permalink)
Senior Member
 
Wilder Amplification's Avatar
 
Join Date: Oct 2009
Location: Fresno, CA
Posts: 6,165
Send a message via AIM to Wilder Amplification Send a message via MSN to Wilder Amplification Send a message via Yahoo to Wilder Amplification
Re: 12AX7 and 12AX7A Whats the difference

When dealing with current production valves, the suffixes in valve numbers don't mean shit. Valve makers/dealers try to use them to denote some difference in gain factor, vacuum hardness, etc etc. Problem is that every company uses them differently and there's no "standard" as to how they're used.
__________________
Jon Wilder

Wilder Amplification - The official home of the 80s cock of the walk "Schwank"

http://www.wilderamps.com

http://www.facebook.com/wilderamps
Wilder Amplification is offline   Reply With Quote
Unread 03-28-2010, 09:52 PM   #5 (permalink)
Senior Member
 
MajorNut1967's Avatar
 
Join Date: Jul 2009
Posts: 3,899
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by Wilder Amplification View Post
The suffixes in valve numbers nowadays don't mean shit. Valve makers/dealers try to use them to denote some difference in gain factor, vacuum hardness, etc etc. Problem is that every company uses them differently and there's no "standard" as to how they're used.
So you would plug a 6L6GT into an amp the requires a 6L6GC? Because "The suffixes in valve numbers nowadays don't mean shit." What's the plate & screen spec for a 6L6GC & 6L6GT are they the same? I think you better retract your statement!
MajorNut1967 is offline   Reply With Quote
Unread 03-28-2010, 09:59 PM   #6 (permalink)
Senior Member
 
Wilder Amplification's Avatar
 
Join Date: Oct 2009
Location: Fresno, CA
Posts: 6,165
Send a message via AIM to Wilder Amplification Send a message via MSN to Wilder Amplification Send a message via Yahoo to Wilder Amplification
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by MajorNut1967 View Post
So you would plug a 6L6GT into an amp the requires a 6L6GC? Because "The suffixes in valve numbers nowadays don't mean shit." What's the plate & screen spec for a 6L6GC & 6L6GT are they the same? I think you better retract your statement!

Show me datasheets for a current production "GC" and "GT". Not original data sheets from back in the day for valves that aren't being made anymore...datasheets for CURRENT PRODUCTION valves.

Now seeing as how this thread is regarding 12AX7s, my statement is correct. Moreover, the OP is referring to current production stuff.

Now since you're talking NOS 6L6GT (seeing as how no one even makes a current production 6L6GT) you would be correct...the ratings for a 6L6GC are drastically different than an NOS 6L6GT so as such you would not want to plug a 6L6GT into an amp that runs over 330VDC on the plates...but when you deal with NOS stuff you have to know your prefixes simply because the suffixes actually did denote different valve ratings/specs during the golden age of valves. But for current production stuff, the suffixes are all used differently and they're typically used to denote a tonal difference, different gain factor, vacuum hardness, etc etc.

One must keep in mind though that not everyone uses NOS valves. Matter of fact, a very small percentage of people do simply due to the cost factor. This doesn't mean that people feel that CP is better than NOS...this simply means that only a small percentage of guitarists can afford to use NOS. And let's face it....once the supply of NOS runs out, it's over/done/gone and you're stuck with CP valves.
__________________
Jon Wilder

Wilder Amplification - The official home of the 80s cock of the walk "Schwank"

http://www.wilderamps.com

http://www.facebook.com/wilderamps
Wilder Amplification is offline   Reply With Quote
Unread 03-28-2010, 10:14 PM   #7 (permalink)
Senior Member
 
MajorNut1967's Avatar
 
Join Date: Jul 2009
Posts: 3,899
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by Wilder Amplification View Post
Show me datasheets for a current production "GC" and "GT". Not original data sheets from back in the day for valves that aren't being made anymore...datasheets for CURRENT PRODUCTION valves.

Now seeing as how this thread is regarding 12AX7s, my statement is correct. Moreover, the OP is referring to current production stuff.

Now since you're talking NOS 6L6GT (seeing as how no one even makes a current production 6L6GT) you would be correct...but when you deal with NOS stuff you have to know your prefixes simply because the suffixes actually did denote different valve ratings/specs during the golden age of valves. But for current production stuff, the suffixes are all used differently and they're typically used to denote a tonal difference, different gain factor, vacuum hardness, etc etc.

One must keep in mind though that not everyone uses NOS valves. Matter of fact, a very small percentage of people do simply due to the cost factor. This doesn't mean that people feel that CP is better than NOS...this simply means that only a small percentage of guitarists can afford to use NOS. And let's face it....once the supply of NOS runs out, it's over/done/gone and you're stuck with CP valves.

After all that you still haven't answered my question! Whats that tell us?
MajorNut1967 is offline   Reply With Quote
Unread 03-28-2010, 10:21 PM   #8 (permalink)
Senior Member
 
Wilder Amplification's Avatar
 
Join Date: Oct 2009
Location: Fresno, CA
Posts: 6,165
Send a message via AIM to Wilder Amplification Send a message via MSN to Wilder Amplification Send a message via Yahoo to Wilder Amplification
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by MajorNut1967 View Post

After all that you still haven't answered my question! Whats that tell us?
Actually....read it again. I DID answer your question...did you not see where I stated -

"Now since you're talking NOS 6L6GT (seeing as how no one even makes a current production 6L6GT) you would be correct...the ratings for a 6L6GC are drastically different than an NOS 6L6GT so as such you would not want to plug a 6L6GT into an amp that runs over 330VDC on the plates...but when you deal with NOS stuff you have to know your prefixes simply because the suffixes actually did denote different valve ratings/specs during the golden age of valves. But for current production stuff, the suffixes are all used differently and they're typically used to denote a tonal difference, different gain factor, vacuum hardness, etc etc."

However...I've just corrected my semantical errors in my original posts so this should be a non-issue.
__________________
Jon Wilder

Wilder Amplification - The official home of the 80s cock of the walk "Schwank"

http://www.wilderamps.com

http://www.facebook.com/wilderamps
Wilder Amplification is offline   Reply With Quote
Unread 03-28-2010, 10:41 PM   #9 (permalink)
Senior Member
 
TwinACStacks's Avatar
 
Join Date: Mar 2009
Location: DETROIT Suburbs
Posts: 14,426
Re: 12AX7 and 12AX7A Whats the difference

Jeez and here all this time I thought GT meant Groove Tubes and GC meant Guitar Center....


Here check this out: http://frank.pocnet.net/

TWIN
__________________
Quote:
Originally Posted by triftstrassa View Post
Are you retarted?
Quote: longfxukxnhair
I knew they were wrong. I can find my ass with both hands

Jm D1 Trusted by more musicians than Fed Ex

Want to make GOD laugh? Tell him about your plans.
TwinACStacks is offline   Reply With Quote
Unread 03-28-2010, 10:46 PM   #10 (permalink)
Senior Member
 
Wilder Amplification's Avatar
 
Join Date: Oct 2009
Location: Fresno, CA
Posts: 6,165
Send a message via AIM to Wilder Amplification Send a message via MSN to Wilder Amplification Send a message via Yahoo to Wilder Amplification
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by TwinACStacks View Post
Jeez and here all this time I thought GT meant Groove Tubes and GC meant Guitar Center....


Here check this out: Frank's electron Tube Data sheets

TWIN
If the GT is a PRE-fix it is.
__________________
Jon Wilder

Wilder Amplification - The official home of the 80s cock of the walk "Schwank"

http://www.wilderamps.com

http://www.facebook.com/wilderamps
Wilder Amplification is offline   Reply With Quote
Unread 03-28-2010, 10:52 PM   #11 (permalink)
Senior Member
 
TwinACStacks's Avatar
 
Join Date: Mar 2009
Location: DETROIT Suburbs
Posts: 14,426
Re: 12AX7 and 12AX7A Whats the difference

Did You check out that Tube Data Sheet Jon? It's pretty handy for reference.

TWIN
__________________
Quote:
Originally Posted by triftstrassa View Post
Are you retarted?
Quote: longfxukxnhair
I knew they were wrong. I can find my ass with both hands

Jm D1 Trusted by more musicians than Fed Ex

Want to make GOD laugh? Tell him about your plans.
TwinACStacks is offline   Reply With Quote
Unread 03-29-2010, 01:09 AM   #12 (permalink)
Super Moderator
 
Adwex's Avatar
 
Join Date: Sep 2006
Location: I'm not sure.
Posts: 9,056
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by MajorNut1967 View Post

After all that you still haven't answered my question! Whats that tell us?
How 'bout a friendly discussion, instead of a fight.
No need for hostility.
Adwex is offline   Reply With Quote
Unread 03-29-2010, 03:01 AM   #13 (permalink)
Senior Member
 
core's Avatar
 
Join Date: Dec 2009
Posts: 1,312
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by TwinACStacks View Post
Jeez and here all this time I thought GT meant Groove Tubes and GC meant Guitar Center....


Here check this out: Frank's electron Tube Data sheets

TWIN
Not sure what the GT is but I do know original 6L6 valves had metal canisters and were developed by RCA. When they went to glass tubes instead they added the G to the end of the model number. From what I read on them it seems it's part of a series G, GA, GB, 5881, 5932, 7027, and the final version 6L6GC.
__________________
♠ ♠ ♠ ♠ ♠ ♠ ♠ ♠ ♠
Aces & 8's
core is offline   Reply With Quote
Unread 03-29-2010, 04:01 AM   #14 (permalink)
Senior Member
 
MajorNut1967's Avatar
 
Join Date: Jul 2009
Posts: 3,899
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by TwinACStacks View Post
Jeez and here all this time I thought GT meant Groove Tubes and GC meant Guitar Center....


Here check this out: Frank's electron Tube Data sheets

TWIN
LOL great one Twin! Frank's site is one of the best tube data sites there is, nice call.
MajorNut1967 is offline   Reply With Quote
Unread 03-29-2010, 04:05 AM   #15 (permalink)
Senior Member
 
MajorNut1967's Avatar
 
Join Date: Jul 2009
Posts: 3,899
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by core View Post
Not sure what the GT is but I do know original 6L6 valves had metal canisters and were developed by RCA. When they went to glass tubes instead they added the G to the end of the model number. From what I read on them it seems it's part of a series G, GA, GB, 5881, 5932, 7027, and the final version 6L6GC.
Core in the final version (6L6GC) was there quite an increase in Plate & Screen voltage specs? I don't really know the chronology of the 6L6 well. Thanks! I personally think the GT suffix is a more recent marketing of the tube.
MajorNut1967 is offline   Reply With Quote
Unread 03-29-2010, 08:50 AM   #16 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: Massena, NY
Posts: 662
Re: 12AX7 and 12AX7A Whats the difference

I have a chance to buy 2 12AX7A USA NOS for about 40 bucks, hence my question. Can I run a standard 12AX7 with these 2 other tubes or would it be better to find a 3rd 12AX7A tube. If so, can someone hook me up, RE Martystrat.
__________________
Bill Griffith Paramedic/Firefighter/Diver
Current Gear:
Left hand guitars:
2009 Gibson SG Standard

Amp:
1982 JCM 2204
1960A Cab
Marshall MG10


Good transaction members: timgman, beamer23, Joey Voltage(for amp service A+++), RJohns, JCarno, Chuckharmonjr, MM54, Martystrat54, ant_riv

ALL WORK DONE ON MY AMPS BITCHINGLY DONE BY JOEY VOLTAGE--ROCK ON
Paramedic006 is offline   Reply With Quote
Unread 03-29-2010, 11:15 AM   #17 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: Massena, NY
Posts: 662
Re: 12AX7 and 12AX7A Whats the difference

Are 2 of these 12AX7A USA tubes worth 35 shipped.
__________________
Bill Griffith Paramedic/Firefighter/Diver
Current Gear:
Left hand guitars:
2009 Gibson SG Standard

Amp:
1982 JCM 2204
1960A Cab
Marshall MG10


Good transaction members: timgman, beamer23, Joey Voltage(for amp service A+++), RJohns, JCarno, Chuckharmonjr, MM54, Martystrat54, ant_riv

ALL WORK DONE ON MY AMPS BITCHINGLY DONE BY JOEY VOLTAGE--ROCK ON
Paramedic006 is offline   Reply With Quote
Unread 03-29-2010, 01:58 PM   #18 (permalink)
Senior Member
 
Wilder Amplification's Avatar
 
Join Date: Oct 2009
Location: Fresno, CA
Posts: 6,165
Send a message via AIM to Wilder Amplification Send a message via MSN to Wilder Amplification Send a message via Yahoo to Wilder Amplification
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by Paramedic006 View Post
I have a chance to buy 2 12AX7A USA NOS for about 40 bucks, hence my question. Can I run a standard 12AX7 with these 2 other tubes or would it be better to find a 3rd 12AX7A tube. If so, can someone hook me up, RE Martystrat.
Yes, and yes. And if you want a 3rd to go with it, Marty can definitely hook you up.
__________________
Jon Wilder

Wilder Amplification - The official home of the 80s cock of the walk "Schwank"

http://www.wilderamps.com

http://www.facebook.com/wilderamps
Wilder Amplification is offline   Reply With Quote
Unread 03-29-2010, 02:21 PM   #19 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: Massena, NY
Posts: 662
Re: 12AX7 and 12AX7A Whats the difference

Thanks Jon. I have no knowledge of NOS tubes and I didn't wanna get them in an uninformed way. I read so much on here about NOS vs CP and I'm gonna start small to see if I can tell the difference.
__________________
Bill Griffith Paramedic/Firefighter/Diver
Current Gear:
Left hand guitars:
2009 Gibson SG Standard

Amp:
1982 JCM 2204
1960A Cab
Marshall MG10


Good transaction members: timgman, beamer23, Joey Voltage(for amp service A+++), RJohns, JCarno, Chuckharmonjr, MM54, Martystrat54, ant_riv

ALL WORK DONE ON MY AMPS BITCHINGLY DONE BY JOEY VOLTAGE--ROCK ON
Paramedic006 is offline   Reply With Quote
Unread 03-29-2010, 03:52 PM   #20 (permalink)
Super Moderator
 
MartyStrat54's Avatar
 
Join Date: Feb 2009
Location: Now in Muskogee, by Tulsa
Posts: 25,981
Send a message via Yahoo to MartyStrat54
Re: 12AX7 and 12AX7A Whats the difference

If you are buying two 12AX7A's, they will work no problem with a 12AX7.

What brand are they? Do they come with any test results? What brand of tester?

$35 for two isn't bad as that would be in the same price range as two current production Tung-Sol's.

Shoot me a little more info and I can help you out.
__________________


MartyStrat54 is offline   Reply With Quote
Unread 03-29-2010, 04:20 PM   #21 (permalink)
Senior Member
 
core's Avatar
 
Join Date: Dec 2009
Posts: 1,312
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by MajorNut1967 View Post
Core in the final version (6L6GC) was there quite an increase in Plate & Screen voltage specs? I don't really know the chronology of the 6L6 well. Thanks! I personally think the GT suffix is a more recent marketing of the tube.
I agree, I would say Groove Tubes added it for their own marketing.

I'm not a tech and I know it's wikipedia so take the info with a grain of salt but it seems to jive with other info I've read up on 6L6's. Still learning here
6L6 - Wikipedia, the free encyclopedia

"...the final version 6L6GC had glass envelopes, which made radiation cooling of the anode easier. The voltage and power rating of the 6L6 series were gradually pushed upwards by adding features such as a micanol base, thicker plates, thicker grid wires, grid cooling fins, and special ultra-black plate coatings. The original metal version was rated for 19 watts dissipation while the later 6L6GC is usually rated for 30 watts."

Cathode
Cathode type: Indirectly heated
Heater voltage: 6.3
Heater current: 900 mA

Anode
Max dissipation Watts: 30
Max voltage: 500
Specification listed is for the type 6L6-GC

Apparently the original metal versions had the shell connected to pin 1 so that's why the glass versions don't have pin 1 connected I assume. No need to right?
__________________
♠ ♠ ♠ ♠ ♠ ♠ ♠ ♠ ♠
Aces & 8's
core is offline   Reply With Quote
Unread 03-29-2010, 04:24 PM   #22 (permalink)
Senior Member
 
MajorNut1967's Avatar
 
Join Date: Jul 2009
Posts: 3,899
Re: 12AX7 and 12AX7A Whats the difference

Quote:
Originally Posted by core View Post
I agree, I would say Groove Tubes added it for their own marketing.

I'm not a tech and I know it's wikipedia so take the info with a grain of salt but it seems to jive with other info I've read up on 6L6's. Still learning here
6L6 - Wikipedia, the free encyclopedia

"...the final version 6L6GC had glass envelopes, which made radiation cooling of the anode easier. The voltage and power rating of the 6L6 series were gradually pushed upwards by adding features such as a micanol base, thicker plates, thicker grid wires, grid cooling fins, and special ultra-black plate coatings. The original metal version was rated for 19 watts dissipation while the later 6L6GC is usually rated for 30 watts."

Cathode
Cathode type: Indirectly heated
Heater voltage: 6.3
Heater current: 900 mA

Anode
Max dissipation Watts: 30
Max voltage: 500
Specification listed is for the type 6L6-GC

Apparently the original metal versions had the shell connected to pin 1 so that's why the glass versions don't have pin 1 connected I assume. No need to right?
Thanks Mate, great info! It is much higher spec then the previous versions!
MajorNut1967 is offline   Reply With Quote
Unread 03-29-2010, 04:37 PM   #23 (permalink)
Senior Member
 
core's Avatar
 
Join Date: Dec 2009
Posts: 1,312
Re: 12AX7 and 12AX7A Whats the difference

Yes sir!
__________________
♠ ♠ ♠ ♠ ♠ ♠ ♠ ♠ ♠
Aces & 8's
core is offline   Reply With Quote
Unread 03-29-2010, 06:48 PM   #24 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: Massena, NY
Posts: 662
Re: 12AX7 and 12AX7A Whats the difference

I will try to get you some info Marty.
__________________
Bill Griffith Paramedic/Firefighter/Diver
Current Gear:
Left hand guitars:
2009 Gibson SG Standard

Amp:
1982 JCM 2204
1960A Cab
Marshall MG10


Good transaction members: timgman, beamer23, Joey Voltage(for amp service A+++), RJohns, JCarno, Chuckharmonjr, MM54, Martystrat54, ant_riv

ALL WORK DONE ON MY AMPS BITCHINGLY DONE BY JOEY VOLTAGE--ROCK ON
Paramedic006 is offline   Reply With Quote
Unread 03-29-2010, 06:50 PM   #25 (permalink)
Senior Member
 
Join Date: Oct 2009
Location: Massena, NY
Posts: 662
Re: 12AX7 and 12AX7A Whats the difference

All I know right now is that they say 12AX7A USA
__________________
Bill Griffith Paramedic/Firefighter/Diver
Current Gear:
Left hand guitars:
2009 Gibson SG Standard

Amp:
1982 JCM 2204
1960A Cab
Marshall MG10


Good transaction members: timgman, beamer23, Joey Voltage(for amp service A+++), RJohns, JCarno, Chuckharmonjr, MM54, Martystrat54, ant_riv

ALL WORK DONE ON MY AMPS BITCHINGLY DONE BY JOEY VOLTAGE--ROCK ON
Paramedic006 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 01:32 AM.


Find us on Facebook!   Follow us on Twitter!

Our Network: PRS Guitar Forum | Luthier Forum | SG Guitar Forum | Les Paul Forum | Music Gear Forum | 7 String Guitar Forum | Acoustic Guitar Forum

MarshallForum proudly supports St. Jude Children's Research Hospital

Copyright © 2005-2014, MarshallForum.com. All Rights Reserved.