What can you tell me about these tubes in my 1987? 6CA7 / EL34.

[TheOtherEric]

My '73 1987 came with these tubes, which are only labeled: 6CA7 EL34 USA. I don't have any experience with 6CA7/EL34 tubes, so I could use some guidance as to what I have and what folks generally think of their quality. I also don't understand the meaning of the 23.0 and 23.5 markings.

The amp is totally stock, and sounds really good. I have them biased at around 63% dissipation.

 

[Maggot Brain]

I believe 6CA7 are US equivalent to UK EL34.

Other than that I have no experience with 6CA7s other than a lot of guys dig em.

 

[fitz]

My '73 1987 came with these tubes, which are only labeled: 6CA7 EL34 USA. I don't have any experience with 6CA7/EL34 tubes, so I could use some guidance as to what I have and what folks generally think of their quality. I also don't understand the meaning of the 23.0 and 23.5 markings.

The amp is totally stock, and sounds really good. I have them biased at around 63% dissipation. View attachment 113979

To the best of my limited knowledge, the current production 6CA7 is equivalent to, but slightly different than the EL34.
At certain points in time, certain manufacturers called them the same thing - like the dual label on those.
They are interchangeable in most amps, and those tubes "look" more like 6CA7 than EL34 to me.

Here's some descriptions from JJ:

JJ Electronic - 6CA7

JJ Electronic - Vacuum tubes, Capacitors, Amplifiers

www.jj-electronic.com

JJ Electronic - EL34

JJ Electronic - Vacuum tubes, Capacitors, Amplifiers

www.jj-electronic.com

 

[yladrd61]

Those are the real deal Sylvania USA 6CA7's

 

[yladrd61]

Those are currently selling for about $500 a pair!!!

 

[Matthews Guitars]

Eddie Van Halen preferred those tubes in his Marshalls. Sylvania dual getter 6CA7s. The numbers are a reference for when they were matched by current draw. If they're still good running tubes, use them. They're very prized.

 

[TheOtherEric]

Those are the real deal Sylvania USA 6CA7's

Those are currently selling for about $500 a pair!!!

Whoa. Guess I gotta research that now, because that would be an attractive price.

Eddie Van Halen preferred those tubes in his Marshalls. Sylvania dual getter 6CA7s. The numbers are a reference for when they were matched by current draw. If they're still good running tubes, use them. They're very prized.

Well, this amp gets me the best EVH tone I’ve ever gotten from many attempts, so maybe that’s not too surprising!

Guess I really got lucky.

 

[yladrd61]

I pulled the original quad out of my Music Man HD 130 and they were still operational after running at over 700 V b+ for over 40 years.