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VERY BIG difference in pre-amp tubes

Discussion in 'Amps and Cabs [BG]' started by yamaha, Mar 20, 2009.

  1. yamaha


    Apr 7, 2006
    In my mpulse 360, I decided to try out a few tubes out.

    Originals were 12ax7-a Mesa

    Tried sovtek 12ax7lps. As many said, this is a high gain that really easely distorts, but a very nice distortion is produced. Overall volume dropped though.

    Tried 12ax7EH. Very clean, very nice. Much cleaner tone than with the originals. But again, significant overall volume drop.

    Anyone else has experience playing around with the simul-state series of Mesa amps.
  2. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I have had a lot of fun rolling preamp tubes in my Walkabout. IME, the M-Pulse line from Mesa/Boogie are some of the more 'responsive' heads when it comes to swapping preamp tubes. Conversely, my Eden Navigator sounds pretty much the same, no matter which preamp tube I try.

  3. chadds


    Mar 18, 2000
    Despite the fact that some say here that you have to a/b/x them when I already own a box of 12ax7s I don't choose what costs more but what sounds like I want it to sound.

    Perhaps some folks don't trust their own motivation and really need science to take the place of choosing what they want. I just put a tube in and if it doesn't sound like I want it to I choose another.

    Thank God they aren't there on my gigs when I roll up a little more mids for punch or treble cause I would swear I did it because I wanted to whether NIH agrees or not.

    It's kind of like picking out socks in the morning.

    Do you need Science or God to choose or is it okay that you choose? Say, given your God given sense of taste or scientific ability.
  4. Bongolation


    Nov 9, 2001
    No Bogus Endorsements
    The first duty of a tube is not to fail or go microphonic.

    The 12AX7LPS is indeed a nice tube, but it's a fragile longplate.

    Unless I'm trying to fix a specific problem -- and certain tubes often produce objectionable noise floors in some amps -- I go for the most rugged tube that will do the job.

    That's usually a selected, bulletproof OEM ultra-shortplate Sovtek 12AX7WA that probably came in the amp -- which also goes in a surprisingly large number of specially prepared major act touring amps. Why? See line #1.
  5. My feeling has always been that the differences people report with different tube brands (which seem to be all over the map, with various TBers describing gain, tone and impact totally different from one another for the same brand and model of preamp tube) has more to do with general tube to tube variability versus manufacturer, age, etc. (to your point above).
  6. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    There are generalizations that sort of work but in general there are far too many variables to predict the results, thats why I have a big bowl full of 12 AX7's for tuning purposes.
    They are just flavors in a recipe.
  7. Rockbobmel

    Rockbobmel Supporting Member

    Unfortunately , most of the reviews that you read are ALL about guitar ears. Rarely do you find talk on bass preamp results.
  8. I was only speaking of all the TB threads comparing various tubes in different pre's. There is very little consistency across reviews when talking about different brands of tubes. This, to me, suggests that the 'brand' is probably not the defining concept across tubes, but rather more random 'tube by tube' variation that overwhelms any consistent brand differences.

    Just a theory of mine!
  9. jeff62

    jeff62 Supporting Member

    Oct 24, 2005
    Orlando, FL
    I haven't found that a "very big" difference exists between tubes, it's more of a "variation in characteristic" in my own tube rolling experiences. YMMV.

    My favorite 12ax7's are the gold pin JJ's and the NOS JAN-Phillips..
  10. One Drop

    One Drop

    Oct 10, 2004
    Swiss Alps
    I've had good consistent results with NOS JAN Phillips. Military grade so you know they'll always come out fighting...

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