Help! Tube Noob

[isher1992]

So, I've found in a closet of my departed grandfather's, several tubes of varying kinds. I have a 12AX7-based Tube pre-amp, and it's the only piece of tube equipment I own. I'd like to be able to sort through these tubes and find out what fits and what doesn't.

Here's the list of what I have:

Sylvania 12AU7A
General Electric 12AU7A

Emerson 12AU7

Raytheon 6U8A

Emerson 6B27

Any help or information is appreciated.

[chillerthanmost]

12AU7 will fit in place of a 12AX7 but will give you much less gain. Closer to around 60% LESS gain. I like those a lot, specially GE. Try them out and see of you like the sound.

[JimmyM]

The 12au7's are still commonly used in amps. The other two are TV tubes, apparently not worth a whole lot.

[isher1992]

@JimmyM: Thanks for the info! I've seen some of your other posts about tubes and they helped me when picking out a tube for the preamp when I bought it.

@chiller: I probably will...It's a boost more than tone shaping (Just a mic preamp to boost the signal to my amp...), so I'll try the GE.

[BurningSkies]

The Emerson is a rebranded something (could be something nice)...the Sylvania will be a nice toob too...don't discount that one by any means. I see that many Emerson tubes are rebranded RCA...

[isher1992]

I'm not sure they all work yet. My grandfather had a bad habit of keeping bad parts on his shelves as a reference for later repalcements (A bad habit I've started to pick up on), so we shall soon see.

[isher1992]

The Emerson was okay. Kind of...wasn't as warm as the JJ's 12AX7 that was already in it. Now the GE 12AU7A...WOW. That's nice and warm, and it doesn't sound driven cranked all the way up. Marvelous.

[Bassflute]

Originally Posted by chillerthanmost

12AU7 will fit in place of a 12AX7 but will give you much less gain. Closer to around 60% LESS gain. I like those a lot, specially GE. Try them out and see of you like the sound.

Originally Posted by isher1992

The Emerson was okay. Kind of...wasn't as warm as the JJ's 12AX7 that was already in it. Now the GE 12AU7A...WOW. That's nice and warm, and it doesn't sound driven cranked all the way up. Marvelous.

not only are they lower gain, they will also overdrive much sooner...you'll wind up with less dynamic range, as the tube ramps up into distortion much quicker (with the gain setting the same as your 12AX7).

But they might sound nice if you don't push them too hard.

Cheers,
Cameron

[chillerthanmost]

Originally Posted by isher1992

The Emerson was okay. Kind of...wasn't as warm as the JJ's 12AX7 that was already in it. Now the GE 12AU7A...WOW. That's nice and warm, and it doesn't sound driven cranked all the way up. Marvelous.