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Your preference: 9V vs. 18V

Discussion in 'Pickups & Electronics [BG]' started by PanteraFan, May 30, 2001.


  1. Just wanted to know which of you preferred 18V over 9V, or vice versa, and why. Hell, even if you like 27V better than both!:D

    Thanx
     
  2. bassmonkeee

    bassmonkeee Supporting Member

    Sep 13, 2000
    Decatur, GA
    I just had Curbow drop an EMG 18V preamp into my int'l petite 5 string. I couldn't be happier with the results. The combination of the EMG and the Bart pickups is astoundingly clear. I have the bass strung up EADGC with TI Jazz Flat strings, and it is the clearest bass I have ever played.

    With the old Bartolini preamp, The bass would distort when I dug in really hard, but the EMG can handle anything the pickups hear.

    I haven't noticed a problem with battery life, either. But, I would definitely make sure to bring a couple of spare batteries to any gig. But, i did that with the 9V preamp, too. Murphy's Law keeps me from even playing with fate like that.

    At some point, I'll get around to uploading some stuff I've recorded with the bass, but it's still going to be a couple of weeks.
     
  3. I've heard about a sort of "Fanthom Power" for basses with active circuitry, so they provide +9Vdc through the jack cable. the Tech21Sansamp seems to have this feature. does anyone know any basses or cables that support this feature? sounds very interesting.
     
  4. rickbass

    rickbass Supporting Member

    As a matter of fact, I have the spec's for a custom with a 27V system at the luthier's right now.

    Why 27V? Transient response. More power = more headroom, so the signal doesn't peak out readily.

    We don't know if it will work, though. The guy who handles the eastern U.S. for Bartolini couldn't tell me if it would fry the preamp.
     
  5. Yes, I understand why you need more power(more power-less chance of overdrive, additional cleaner tone) but I've read somewhere on the internet that the difference between 27 and 18 is nowhere near as clear as 9 and 18.

    Which Bart preamp are you interested in? Heck, if it comes down to it, you could solder a resistor or two on the preamp board, but then the preamp may sound dull and unresponsive. Tell me the model code, and I'll surf to the Bart website and see if I can apply a couple of electronics formulae(namely V=IR, etc.)
     
  6. Mark Gollihur

    Mark Gollihur Supporting Member Commercial User

    Jul 19, 2000
    Gloucester County, NJ
    Owner/President, Gollihur Music LLC
  7. rickbass

    rickbass Supporting Member


    Thanks, Rex....I mean PanteraFan. I'm not expecting a big difference if it can be done. Scott Malandrone, who used to do some stuff for Bass Player, said some players don't hear the difference. I don't find some pickups acceptable that some others have thought were just fine, so, I guess my ear is picky.
    The first thing he said they heard was faster attack. So, it may enhance my slapping. In addition, the style I've developed over the years involves many "milli-plucks" of the same note as I tend to sort of play the hi-hat on the bass. They also noticed more low end bloom, and I'm always after that.

    The Bartlolini harness I've spec'd is their HR4.4AP. It doesn't show up in their catalog. Grasshopper, the Bartolini guru at Bass Central, turned me on to it. It's $11 more than their regular harnesses but he said it is the nuts. It gives more tweakability to the mids.

    As long as I was having a custom made, I figured why not try something I can't get off the rack?

    It sounds as if you may know, on paper, if this would fry the preamp. I appreciate your interest and expertise. The luthier was schooled as an electrical engineer but he hasn't passed judgement yet. So, I'd certainly be interested to hear your input.
     
  8. RAM

    RAM

    May 10, 2000
    Chicago, IL
    My EBS Fafner is designed to do just this:D I'm told that while it doesn't come wired as such, any repair shop that's authorized by EBS to make the minor modification can do so quite simply! I can therefore, theoretically, power either a pedal or my bass with about 10 volts or so. The problem with this is that my bass runs on 18, so it won't work all too well.

    On my Fender, however, if I had an active preamp (which I may evenually install), I would have to have the bass wired in stereo in order to use this feature. Again, this is not difficult for most repair shops. But, the idea with the stereo wiring is that you've got 2 signals, but one is the power running into the bass, where the other is the signal FROM the bass to the amp.

    I agree about it being cool, though...it could mean no more dead batteries:D
     
  9. It's quite simple really. You take the maximum number of amps(current) that the preamp can take, then substitute it into the V=IR formula. You then take the overall resistance of the preamp, and substitute that in. You multiply the two to find the total number of volts that can be handled by the preamp. This is perhaps one of the most simple electronic formulae, and is used extensively in Physics studies too.

    But, if the preamp is not in the catalog, then I'm not sure about how you could find out these very specific details.

    The closest I can find in the Bart catalog is the Hr4.4, set up as Vol-Vol-Tone-Tone, with a stacked Treble/Bass and a push-pull mid. I'm not sure what the AP version has, but even so, the specific details are not listed anyway.

    How's Bill Bartolini for answering emails?:D
     
  10. rickbass

    rickbass Supporting Member

    My guess is the "AP" isn't significantly different in its basic spec's, but it would still be good to get the 27V blessed by someone who could say for sure.

    E-mails appear to be a lost cause, from what I see posted at the site, unless you have a malfunctioing product of his. I sent one that was ignored. However, you can telephone at certain hours on certain days posted at the site when they take calls.
     
  11. Good afternoon Gents.

    Just thought I'd pop in here and throw more confusion to the lions...!!!!!

    PanteraFan, sorry, but your reasoning doesn't make much electronic sense. The preamp will consume whatever current the designer has asked it to take. That will be a combination of a variety of factors. You can't really measure the resistance of a preamp in a static sense - not powered up - with something like a multimeter. It does have a dynamic resistance when it's powered up. You can effectively calculate that knowing the current it takes (measured with a multimeter) and the battery voltage, also measured with a multimeter.

    R=V/I.

    But knowing R doesn't get you anywhere.

    To know whether or not any given active circuit will take an uplift in batt volts - say from 9 to 18 - you need to know at the very least:-

    1) The part number of the chip(s) so that you can consult manufacturer's technical data sheets to find out the max permitted voltage the device can withstand. THIS IS VITAL. Sometimes that part numbers are deliberately removed / altered.

    2) The circuit diagram of the actives (which you'll amost certainly not get 'cos makers keep them secret). Without getting over flash, the way the designer has arranged the onboard voltage rails will need to be considered before you mod tha active. Getting it wrong (could) = smoke.

    This uplift in batt voltage has to be considered with circumspection. Don't whatever you do, just go for it hoping for the best.

    If you know a friendly electronics man have him look over the actives. If he'll draw the schematic from the circuit board for you - not all that difficult, here - buy him some smokes or a beer. It'll be well worth it.

    Hope that helps.

    Rockin John
     
  12. eric atkinson

    eric atkinson "Is our children learning "Is our teachers teachin

    Feb 4, 2001
    Joplin,Missouri
    Not sure yet i will tell you soon when i get my spector usa bolt on in that i orderd with the 18 volt optional aguiler!
     
  13. rickbass

    rickbass Supporting Member

    Rockin' - All that tech stuff you understand that looks like mumbo-jumbo to me? That's why I'm leaving it to the pros.

    Brad Johnson tipped me off that it appears Lane Poor is back on the planet, so, I chucked the Bartolini pups and harness temporarily, until Lane Poor answers my email about whether a 27V system will fry his preamp or not.
     
  14. Good morning Rickbass1. How are you? Good.

    I think you can take some heart from 'all the tech stuff' you say I understand!!

    Actives filters, small signal amplifiers and the like are usually built around / with what's know as operational amplifiers - op. amps. for short. They're nothing more than little anologue building blocks. You set up the correct DC conditions around them by whatever means then stuff the (bass in this case) signal into it and it comes out modified.

    These op amps have a rating given to them which specifies how much voltage you can put across them before they smoke - generally not put like that in a tech data sheet!!!!!! Most op amps these days will withstand +-15Volts = 30 volts absolute max. Some got to +-18, and some are +-20 and more. A good circuit design would set the supply voltage to a few volts less than 'smoke' voltage.

    All other things considered and assuming your actives use op amps and not some special chip, going from 9V to 18V should be no problem. Going from 18 to 27 probably won't either but this is the point where you need to know exactly what chip is in your actives BEFORE you actually try the voltage uplift.

    I'll be pleased to help you with this if you can (1) get access to the chip(s) and (2) read ALL the numbers on the top and (3) post you findings or email me direct. I'll then see if I can ID the chip(s) and then find out the answers from the data sheets. Naturally I'll have to leave the final decision about the mods to you assuming we can ID the chip. Hope that's OK.

    Leave that one with you, Rickbass1.:D

    Besr regards.

    John
     
  15. rickbass

    rickbass Supporting Member

    Good morning (and good night in a few minutes) to you Rockin'.

    The plot thickens - Now that Lane Poor appears to have returned to this reality, I've shelved the Bartolinis in favor of Poor pups and preamp. Compared to Bartolini, Poor's operation is the Welcome Wagon, (the 3 principle guys take e-mail product questions!).

    So, maybe they will answer the 27V for me. ("How" isn't the question. "Feasibility" is). If not, the luthier's background is electrical engineering, so, I'm not worried about having to buy pups/preamp twice.

    It's still Greek to me. Was Nikola Tesla a close friend of yours??? ;)
     
  16. Well, sir, if they can't answer I'm still willing to try.

    No:D:D:D he wasn't. Tesla coils an' all that stuff is a might frightening.

    Sleep well. (Seems strange saying that when its 11.30am, in UK)

    John