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How important is an 18 volt pre-amp to you?

Discussion in 'Basses [BG]' started by Danham, Dec 30, 2003.

Which one?

Poll closed Jan 13, 2004.
  1. I only like 18 volt basses.

    2 vote(s)
  2. I only like 9 volt basses.

    1 vote(s)
  3. I play either. Depends on the bass.

    46 vote(s)
  4. I only play passive basses.

    10 vote(s)
  1. Danham

    Danham Guest

    Feb 11, 2003
    Shreveport LA
    How important is an 18 volt pre-amp to you? Do you even consider 9 volt basses anymore? Is the difference that big?

    I sent my broken EDA905 (18 volt) into Ibanez yesterday and asked for a SRX705 (9 volt).
  2. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    It all depends. With EMG pickups, I prefer running them at 18V, but with a J Retro preamp, I am completely happy with it at 9V. On top of that, a good passive bass can be killer as well.

    From an engineers perspective, the difference between 9V and 18V is headroom. An 18V supply allows for a larger signal level without distortion. 9 volts should be enough of a supply voltage to get sufficient headroom, but depending on the preamp design, it isn't always so. There is no doubt that some preamps sound better when run at 18V instead of 9V. It is not true of all preamps though.
  3. Jazz Ad

    Jazz Ad Mi la ré sol Supporting Member

    Passive usually for me.
    18 V only means 2 batteries instead of one.
    From the basses I've tried, I haven't been convinced that it could improve anything to go 18V instead of 9V.
  4. Mike Money

    Mike Money In Memoriam

    Mar 18, 2003
    Bakersfield California
    Avatar Speakers Endorsing Hooligan
    My jazz is 9... my peavey G is 18... i wub dem bowth deerelly.
  5. JJd2sc


    Jul 31, 2003
    Marietta, Georgia
    It seems to me that you can do a lot more fine tweaking of tone on an 18 volt preamp.
  6. rickbass

    rickbass Supporting Member

    IMO, it all depends on the bass designer at the time they designed the bass.

    Fr'instance - a good pre-CBS Precis just knocks me out.........no batteries were ever considered in the design.

    But, my custom has an 18V preamp that just cracks walnuts with its tone........not "volume".

    So, the moral of the story I am telling is my usual rant - If it sounds damn fine to you, go for it!!!!
  7. phogchris

    phogchris www.scarsoflife.com

    May 27, 2000
    Boca Raton, FL
    I am very surprised that someone couldn't hear the difference between 9V and 18V in EMG's. After switching my Rebop to 18V, I would never go back to 9....I find 18V run preamps to sound fuller.
  8. I voted for either, but I don't think I could tell the difference anyway.

    Concerning EDA905s, I know I've posted this link a dozen times, but...

    You guys are gettin' it again! :D http://www.ibanez.com/guitars/guitar.asp?model=EDA905

    Seriously, check out at the bottom of the features, where it says EQA-PZ. It says, "18 volt circuitry provides more headroom."

    I took the battery cover off for the first time about a month ago; there's only one battery in there. :rolleyes:

    Is Ibanez trying to pull a fast one?
    Can I just add another battery without screwing anything up?
    Does it really add to the sound?

    Danham, is Ibanez going to replace your bass, or the shipping company?

  9. Danham

    Danham Guest

    Feb 11, 2003
    Shreveport LA

    The EDA has a voltage doubler in it. This essentially means it drains twice as much juice off the one 9V. So it goes through batteries twice as fast. Not really any different to having two 9V's in series.

    Ibanez is replacing my bass. I'm sure they got the insurance money for the busted bass too. I don't care. I just want my SRX705.:bassist:
  10. chucko58


    Jan 17, 2002
    Silicon Valley, CA, USA
    I paid for all my gear myself. Well, me and MasterCard.
    A 9V preamp, if designed correctly, is plenty adequate for most magnetic pickups. Piezos have a much higher output voltage, so they need the extra headroom of an 18V system. Or so says Rick Turner, and I believe him.
  11. AHA! The EDA905 has one magnetic pup, plus piezos!

    Also, the piezos on my bass have a much louder signal unless you adjust it with a rear body-mounted trim pot. I've noticed that when I did this, got the piezo signal about equal with the magnetic pup, the bass lost a lot of its growl.

    Thanks, chucko58.

    And thank you too, Danham. Good luck with the SRX705. ;)

  12. phogchris

    phogchris www.scarsoflife.com

    May 27, 2000
    Boca Raton, FL
    I totally agree with that, but to my ears, the 18V upgrade just makes the bass sound that much better.
  13. My prediction? More and more basses will come with 18V, b/c manufacturers will realize it helps sell instruments.

    Eventually, someone will introduce a three battery system (27V), and the voltage "inflation" will start all over again.
  14. phogchris

    phogchris www.scarsoflife.com

    May 27, 2000
    Boca Raton, FL
    I hope that people can differentiate true improvements from marketing hype. My 9V ZON was as powerful and full sounding as any 18V bass I have ever played. Its so individual to me, basing a purchase on amount of voltage would be ridiculous...lets hope it doesn't come to that.
  15. I read that higher the voltage is the better is the sound produced by the preamp.
    I think Alembic feed their basses with something like 45V(or they did). Does it sound better than a passive or a 9v bass?
    the answer is NO.
    The question is: does a preamp,able to handle either 9 or 18V work better at 18?
  16. Eric Cioe

    Eric Cioe

    Jun 4, 2001
    Missoula, MT
    I think an Aguilar OBP-1 can run at either, so someone with that preamp should try it out.
  17. well id be willing to try but i believe when i switched my batteries I only had one and no other hookups. I have a few year old Spector
  18. bassmonkeee


    Sep 13, 2000
    Decatur, GA
    Status has already released a 28V system on their Jonas Hellborg signature model. It sounds pretty astounding, too.
  19. bucephylus

    bucephylus Supporting Member Commercial User

    Aug 18, 2002
    General Manager TecPadz LLC
    First of all, the amplified instrument consists of the bass and all the gain stages and the speakers. Impressions or opinions about the importance of one of the elements in the "instrument" must be in context to the rest of the rig.

    Secondly, tone is totally subjective. Just how supply voltage levels in one of the gain stages affects tone is not universal. One needs to be careful to differentiate between tone and gain. The additional gain can certainly improve quality of sound for a given rig, but does not neccessarily affect tone.

    Ron Wickersham at Alembic has a strong opinion about placing the gain stage in the instrument to minimize signal degradation getting to the amp. The Series basses do sound righteous.

    At the complete opposite end of the output spectrum is the passive J bass which continues to be a big favorite.

    To make things more confusing, try getting an inexpensive tube microphone preamp, like an ART MP-1. That is basically a leveling amplifier. You will find that you can make any bass output from a Series to a J sound full and toneful.

    My 2c is that the real problem is in the input stages of most amp systems. None of them have sufficient flexibility to deal with the wide range of output from different instruments. Bottom line is you have to match the output of the bass to the input characterisitcs of the amp.

    - pt
  20. Randy Payne

    Randy Payne

    Jan 1, 2001
    I did this experiment a couple of years ago. You may find this interesting, or you may find it overly technical...

    OK folks, here's the results of my 9 vs. 18 volt supply to EMG pickups
    My 9 vs 18 volt EMG pickup supply experiment:

    1) EMG jazz bass pickup (not the vintage or Select, just the standard
    2) Variable 0-20 volt, low ripple DC power supply.
    3) Test bass, which is a Jazz Bass neck mounted on a 2x10 body with
    BadAss bridge. (Yes, I said 2x10, as in what's probably holding up the
    floor you're sitting on) I use this for pickup tests.
    4) B&K oscilloscope
    5) Custom tube bass amp with standard 12AX7 input stage with the usual
    1.5K cathode resistor, 100k plate resistor, etc...

    PART 1 - Oscilloscope
    First I set up the pickup on the test bass as close to the strings as
    possible without striking the strings. Playing was done by slapping, and
    fingerstyle as hard as I possibly can. (I've got plenty of callouses and
    my finger still hurts from this little experiment!) With 9 volts, the
    oscilloscope showed a maximum signal of about 5 volts peak-peak. (I
    looked hard to include the initial transient, and didn't see anything
    above 5 volts p-p. As I ran the voltage up to 20 volts I couldn't see
    much difference. At both 9 and 20 volts, the peaks did not appear to be

    PART 2 - Through amp and listening
    Same setup as in part 1), except the output was going into the usual
    12AX7 input stage. First thing I noticed, is that with the strings at
    minimum distance from the pickup, and my violent, maximum string
    hitting, I was overloading the input of the 12AX7. This is not
    surprising, since 12AX7's have a typical voltage gain of ABOUT a hundred
    or so in this configuration, and the plate supply is 300 volts, so this
    means that 5 volts p-p times 100 gives a first stage p-p voltage of 500
    volts, which means CLIP TIME. So anyway, I retreated to the workshop and
    put a 10:1 attenuator on the pickup, so I could hear the output without
    the distortion form the tube preamplifier. (Pickup output freaks take
    note here, when you get such high outputs, you need to turn down your
    volume control to keep from overloading your input stage, unless this is
    what you want!)
    Anyway, I did a sound test from 9 volts to 20. Maximum force
    fingerstyle and slapping. Well, I either have bad ears OR there is no
    noticable difference in sound quality between 9 and 20 volts. I listened
    for any clipping at 9 volts that was not present at 20; nothing. I
    lowered the supply voltage until I could hear clipping begin, and then
    measured the supply with my DVM. The voltage at the onset of clipping is
    about 5 volts, which is,surprise, about the same voltage as the max. p-p

    PART 3 - Popping
    So am I missing something? How about extreme popping? Back to the
    oscilloscope. Pickups close to the strings, popping by lifting the
    strings an inch or more off the fretboard and releasing them. 8 volts
    p-p right on the attack with 20 volt supply. When the supply is backed
    off to 9 volts, CLIPPING. So OK, 18 volt people, I hear you. Plug the
    bass back into the amp. Pop some more. Try 9 vs. 18. I can't say I hear
    a big difference, because the clipping at 9 volts is on the first few
    cycles of the note anyway.

    In summary, 18 volts will provide extra headroom against clipping for
    really strong popping. For fingerstyle, I think 9 volts is plenty. If
    you're a slap/popper that doesn't play that hard, it's a close call, you

    Keep in ming that I used an EMG-J here, the other types of EMG's may
    have different results.

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