Is the SPAX7 a Better Tube All Around?

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Hendog

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I was wondering... Should I replace all of my preamp tubes with the Mesa SPAX7's? I know they are considered "better", but would they change the charateristics of my amp?
 
Hendog said:
I was wondering... Should I replace all of my preamp tubes with the Mesa SPAX7's? I know they are considered "better", but would they change the charateristics of my amp?

I was wondering that, too. I got 4 of them for my Mark V, and put them in V1-3 and V7. I didn't like the results. It seemed to weaken the tone and make the sound a bit thinner, though it did cut noise and hum considerably. I kept an SPAX7 in V1, though. I like it for V1 better than any other tube so far.
 
I just got a JCM800 that has them in all three preamp spots (!?) It's really, really quiet, even when I slam the front end with an OD, and very clean and articulate. They don't seem super high-gain, though. Definitely a good V1 choice.
 
It really makes a difference to, move around what you have. What I mean is, try what 12ax7's you have in V1, v2,v3, ..... and see where they sound best. Even when you have the same brand 12ax7, they all sound different, somtimes a lot different. It's worth the time, IMHO and it dosen't cost any money.
 
I recently did a retube to my Nomad 55 combo.
For me, I went with Tung-sols in V 1,2 and 3. I put SPAX7 tubes
in V4 and 5. Sounds killer.
YMMV.
 
The SPAX7 is designed for the V-1 slot as this is the first gain stage and does the most work. Not being a tube guru I'm not sure if it's actually a different designed plate structure, just more insolation on the galss, or a combination of the 2. Someone may be able to chime in.
 
When Mesa tests tons of 12AX7s, the SPAX7s are ones that test lowest in noise. Visually identical to their noisier brothers, they're just quieter. Then they wrap them to further ensure against microphonics.
None of any of this has anything to do with tone.
 
I am using a SPax7 in my V1 for my LSC. Much quieter and I noticed that it appears to have shrink wrap tubing around it. I assume this is to cut down on the vibrations.

My question is - can folks put shrink wrap on all of the 12ax7 tubes hurting them (maybe they would get too hot)? Does Mesa use something special for their shrink wrap?


Just curious.


Thanks
 
Musical123 said:
I am using a SPax7 in my V1 for my LSC. Much quieter and I noticed that it appears to have shrink wrap tubing around it. I assume this is to cut down on the vibrations.

My question is - can folks put shrink wrap on all of the 12ax7 tubes hurting them (maybe they would get too hot)? Does Mesa use something special for their shrink wrap?


Just curious.


Thanks

I would not do that. Have you called MESA? They can help you out.
 
I had all SPAX7's in my ex-Mark III green with IIC+ OT. All I remember is that amp was a beast, had me kicking the walls in the studio...

Don't recall the noise factor though...
 
I'm looking to retube the preamp section (getting a new quad of JJE34L's now) of my Rivera S120. Should I go with TungSol in V1 or SPAX7? why?
 
The SPAX7 is picked for low noise. Period.
Not for 'better" tone, whatever that is.
Mesa recommends them for V1. Period.
 
Musical123 said:
My question is - can folks put shrink wrap on all of the 12ax7 tubes hurting them (maybe they would get too hot)? Does Mesa use something special for their shrink wrap?


Just curious.


Thanks

Heat shrink tubing should not hurt preamp tubes. The heat generated from the tube might shrink the tubing for you!
 

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