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If 12AX7 and ECC83 are the same...

coldstar

Member
... then why is there an option on the preamp page to change between them? I've always read that 12AX7 and ECC83 were the same thing, but the preamp page is implying to me that they're not. Are they actually different? What's the difference?
 
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electronpirate

Moderator
Moderator
I *believe* that ECC83 is only the British designation for the same tube 12AX7.

My guess would be since there can be such wide variations between the same preamp tube, each will have a slightly different voicing.

-R
 

Ed DeGenaro

Experienced
It kinda depends...yes Ecc83/7025/12ax7/12ax7a are different designations (euro/industrual/US) for twin triodes with a gain multiplier of 100.
Now that said the original 12ax were long plates, then the Euro stuff like mullard and Phillips copied them. It got to the point we're they got imported into the US cause their quality was better/more consistent.
Amperex comes to mind.
Then RCA and GE answered with the 12ax7a a short plate.
Which in turn was also adopted by the Euro makers.
So ecc83 as a designation can mean a variety of things...long plate, shirt plate in the case if mullard also box plate.
I think the difference in sound is more the cathode material that makes the difference.

Also my fave low gain tube a GE5814 is merely a Industrial designation 12au7/ecc82 but no 12au sounds like it
 

kisslorand

Experienced
Take a listen and you'll notice the difference in sound. For me ECC83 sounds with more definition, more in your face.
 
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Ed DeGenaro

Experienced
I suspect the poster means that ECC tube choice within the AxeFx's amp block has more definition, etc. Assuming that's what he means, I'd agree.
Then I agree. But I was under the impression we were talking about tubes rather than the parameter in the preamp.
 

hdurdevic

Member
The parameters for the 12AX7 were extracted from an RCA 12AX7A. The ECC83 was a Mullard.
What was 7025 extracted from? I find myself selecting it lately, finding it does pronounce clarity in tone. A wish while at it: from what I read around the web, adding the 5751 model would be interesting, at least for me.
 

kisslorand

Experienced
Which Ecc...short...long...box plate? An Ecc doesn't sound more in your face by printing ecc83 on it.
The one in the AxeFX, same as the OP is talking about.

... I was under the impression we were talking about tubes rather than the parameter in the preamp.
... then why is there an option of the preamp page to change between them? I've always read that 12AX7 and ECC83 were the same thing, but the preamp page is implying to me that they're not.
 
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