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18v Preamp against 9v Preamp!!!!

Discussion in 'Pickups & Electronics [BG]' started by adisu, Nov 14, 2005.


  1. adisu

    adisu I admit it, I'm a "user"

    Apr 8, 2005
    Israel
    Hi all!!!!

    I bought An aguilar onboard OBP-3 Preamp for my new costum guitar!!!!
    Together with the amp i got two 9v battery carrier.
    The guy on the custom shop said that i don't need them both and he is going to install only 1 battery carrier which means my system will work on 9v only.
    It sound o.k. to me as i thought that the second battery is just a backup for the first battery.
    Today i read for the first time about 18v system in one of the amps forum threads and suddenly i realized that maybe the system needs the all 18v in order to work properly!!!

    Please help....

    Is the second battery is just a backup battery or does the electronics guy in the costum shop don't know anything about onboard preamps and i really need the second battery to work with the system properly ??? :rollno:

    Thanks in advance.
    Adisu
     
  2. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
    You can use the Aguilar with one 9V. I've done it, on 2 different basses. People will tell you that you can't. They're wrong, you can.

    It sounded fine, tho since I only ever used it with one, I can't tell you what (if any) diff there would be with 2. It would most likely have a bit more headroom and be cleaner on attack transients for that reason. Another 9V will not make it any louder tho. Just cleaner, tho as I said with one it sounded just fine both live and in a studio setting.
     
  3. MY OB-3 that came standard on my Jerzy Drozd runs with a single battery. I believe the OB-3 documentation says you get a 6DB boost in output running 18v, but I could be wrong about that. I know my OB-3 has the lowest output of any active bass that I own, and unfortunately does not have an internal pot to adjust output. However, it sounds great.. I just run the input of my amp hotter.
     
  4. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    The text on their website is pretty confusing. Aguilar clarified it for me by email, to whit: The OBP-3 is unity gain. Running on 18V gives you an extra 6dB of headroom.

    So if its output seems low, it's because your pickups are quiet. Not the ideal bedmate for Barts therefore, but great with loud pickups like EMGs.

    Alex
     
  5. SteveC

    SteveC Supporting Member

    Nov 12, 2004
    North Dakota
    18 volt is overkill - IMHO. My 9 can clip my preamp.
     
  6. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    Wrong way round. If you had a higher rail voltage then your (onboard) preamp wouldn't clip.

    Alex
     
  7. Thanks for the clarification. I didn't quite get it. I don't have any trouble with the output. I'm surprised though, that they don't put a trim pot in the circuit like most other preamps. That being said, it is quiet and sounds fine... very 'hi fi' and clean. The very high treble center point is interesting on that preamp... more useful IMO for guys who don't like a lot of high end, since it allows you to reduce the extreme treble response and 'click' with very little impact on the upper mids.
     
  8. Kinda like my EBS preamp which has its treble knob fixed at 10K... that seemed wierd to me at first, but it sounds good - esp for slapping!

    It has a fully sweepable range as well though.
     
  9. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    I think he meant the preamp in his rig, not on his bass! :D
     
  10. Pickebass

    Pickebass Supporting Member

    Jul 12, 2004
    San Antonio, TX
    9v works fine for the OBP-3. The OBP-1 will only work with at least 18v
     
  11. adisu

    adisu I admit it, I'm a "user"

    Apr 8, 2005
    Israel
    COOL!!!!
    Thanks guys I'm much more relaxed right now!!! :smug:

    Logically in science whenever you double a certain amount of volts you always get a 6dB boost. But I wonder if it's really that necessary for getting a better sound or is it just a volume boost???

    Adisu
     
  12. theshadow2001

    theshadow2001

    Jun 17, 2004
    Ireland
    Im not sure. If you use 18V for head room then you surley wouldnt use the pre amp on full volume. That said when has an active bass been known to clip? Mine never has (except when the battery runs out of course) you,ve got to be running the tone controls really hot just to do something like that, like pushing them all up to 11 or something.

    Having the signal larger than what a 9V circuit would supply seems a little strange as well. Because the first thing that happens to your signl when its put into the active input of an amp is that its reduced by I dunno...bout 10dB? Can't any more input volume thats needed just be taken from the gain on the amp

    There must be a good reason for going 18V I just cant see it.
     
  13. I think there is confusion here regarding the concepts of 'headroom', and 'gain'.

    If running at 18V gives 6 dB of extra headroom, it won't be 6 dB louder, just cleaner on transients due to the headroom. 18V does not give 6 dB more gain. The headroom would likely be noticed most by hardcore slappers and those who boost the bass knob all the way.

    FWIW, I run my EMG BTS at 18V, and it doesn't sound much different than at 9V.
     
  14. +1 Good explanation. I was always confused by 'gain' and 'headroom' as it pertained the the 18 vs. 9 volt preamps. It seems like the 18v sytems/option is not that big of a deal. I do use the slap technique on occasion, and have never come close to overdriving my internal preamp (by that, I mean I've never noticed my sytem to have any distortion whatsover).
     
  15. theshadow2001

    theshadow2001

    Jun 17, 2004
    Ireland
    Ok well that makes sense to me
     
  16. I have actually overdriven my 9v preamp on Warwick, but I thought that was just due to my pickups being too high/close to the strings? I lowered them and viola! no more distortion on hard slapping... maybe an 18v system would have been able to handle it better?
     
  17. TaySte_2000

    TaySte_2000

    Jun 23, 2001
    Manchester, UK
    Endorsing Artist: Mojohand, Subdecay, Overwater, Matamp
    fishman do a voltage doubler or something so you can run a single 9v battery and it powers 18v electronics I have one in my Valenti
     
  18. adisu

    adisu I admit it, I'm a "user"

    Apr 8, 2005
    Israel
    I learn sound engineering at college and today i asked my lecturer about this issue.
    He said that other than avoiding distortion the extra 6dB gives you a better SNR (Signal to Noise Ratio) which means you can play louder and get less noise (hiss) into your recording or playing at shows.

    Thanks everyone for your replies!!!
     
  19. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
    This is commonly believed, but is not correct. I used 2 different basses with the OBP-1 (the 2 I referred to earlier), and in both cases I ran only one 9V battery. It worked fine in both cases.
     
  20. I have run EMGs on 18v and the increase headroom certainly is noticeable.