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Can I Use an Active Preamp For an Amp's Preamp?

Discussion in 'Pickups & Electronics [BG]' started by Float on man, Nov 16, 2018.


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  1. Float on man

    Float on man

    Mar 10, 2018
    I'm building a basic amp out of a literal cardboard box and so far all I've got is a master volume. I want to add a 2 band eq but are amp preamps different from the preamps found in active basses? If so, will this cause any problems if I use an active basses’s preamp for an amp preamp? Thanks you have a nice day.
     
    Last edited: Nov 18, 2018
  2. Jeff Scott

    Jeff Scott Rickenbacker guru.......... Supporting Member

    Apr 11, 2006
    o_O
     
    RickyT, nilorius and Float on man like this.
  3. Float on man

    Float on man

    Mar 10, 2018
    I don’t uderstand what take means but if your confused what I meant to say was, are bass preamps and amp preamps built and wired differently and if they’re made differently, if I use a bass preamp as an amp preamp, will that cause any problems?
     
  4. rufus.K

    rufus.K

    Oct 18, 2015
    SoCal
    Should be fine.
     
  5. Jeff Scott

    Jeff Scott Rickenbacker guru.......... Supporting Member

    Apr 11, 2006
    When you say bass preamp do you mean the type that is found inside basses that are "active"? If that is so, it can be used but usually they do not have a high enough output to drive a power amp sufficiently, if barely at all to reasonable volume levels.
     
    mech and Float on man like this.
  6. Float on man

    Float on man

    Mar 10, 2018
    Thanks man, so, what di you mean “high enough output” exactly. Does that mean more volume or is that a distortion thing? Also, can I just add another 9v into the mix to get a higher output? Thanks again.
     
  7. Jeff Scott

    Jeff Scott Rickenbacker guru.......... Supporting Member

    Apr 11, 2006
    I'm talking about that most onboard type active bass preamps can't produce enough power (volume level) by themselves to drive a power amp to a loud enough level to be of much use in gigging type situations. They are really intended more for buffering the pickup's load and provide some EQ of various sorts, and the output of then would then go into a "bass preamp" that is in one's bass amp, for example. This has nothing to do with distortion, it has ti do with the output of the preamp driving a power amp to its fullest capability. Distortion is a whole other thing.
     
    Last edited: Nov 17, 2018
  8. StatesideRambler

    StatesideRambler

    Jul 1, 2015
    If you want to plug a bass with a built-in preamp directly into a power amp (either power amp input or effects return) then no. It likely won’t harm anything but the results will be, to be charitable, unsatisfying. If you’re thinking of plugging the bass into a pedal preamp like an Ampeg SCR-DI or a Sansamp VT then plugging that into the power amp, then go for it.

    The preamp stage of a bass (or guitar) amp has one or more voltage amplification “stages” that increase the very low voltage from the instrument up to a voltage high enough to “drive” the power amp. There’s lots more to this but them’s the minimum basics.
     
  9. Acoop

    Acoop

    Feb 21, 2012
    If you plug into the Effects loop/input, on you amp, then you're bypassing the amps pre. ... An active bass into an amp is a pre-amp into a pre-amp. ... I run my upright into a Bassbone, (Ch 1/notch) then into the input of my Aguilar 350, because it doesn't have a loop, but it works very well. Just keep your master high and your input gain low and you shouldn't have a problem. Try not to depend on EQ for your sound. ... Cheap pickups into a preamp don't make them better pickups.
     
    40Hz likes this.
  10. DanAdams

    DanAdams Supporting Member

    Nov 3, 2013
    Maine
    All this talk about preamps.........
    I want to hear more about the CARDBOARD BOX CABINET!:hyper:

    The answer should be "no problem" go for it man. Rock out. there is no need to get caught up in what is best when we're talking about a cardboard amp.
    I want pics.
     
  11. nilorius

    nilorius

    Oct 27, 2016
    Riga - Latvia
    It should be fine, but the sound will become a little bit badder.
     
  12. I hesitate to say this because I don’t want to be insulting, but are you sure that it’s safe for you to be making an amp, especially in a cardboard box? I’d be worried about heat or electrical causing a fire. I don’t know much about it, but I know enough that I wouldn’t want to build something myself that I plug in the wall for safety reasons.
     
    96tbird and nnnnnn like this.
  13. I do get a decent sound from an active bass w/ a portable bluetooth speaker. Using a 1/4>1/8 inch jack adapter on the inst. cable. I'd focus on that cardboard cabinet!
     
  14. shwashwa

    shwashwa

    Aug 30, 2003
    NJ
    Preamp pedal or clean gain boost pedal will get you there
     
  15. Jeff Scott

    Jeff Scott Rickenbacker guru.......... Supporting Member

    Apr 11, 2006
    I stayed up all night long thinking about this thread. Has there been any mention of a power amp? I seem to recall only the talk of preamps. ;)

    Regardless, if there is in fact a power amp (made of cardboard, or otherwise) you may get a moderately loud output from it. I can run my passive basses straight into the effects return jack on my Aguilar Tone Hammer 500 and get loud enough for a moderate volume gig. No tone controls, but my rig sound fabulous running flat, so that is of no concern to me, personally.

    BTW, all preamps that are built-in to bass amps are active.
     
  16. DDXdesign

    DDXdesign formerly 'jammadave' Supporting Member

    Oct 15, 2003
    Wash DC metro area
    OP, your first post was possibly confusing because you said "bass preamp AND an amp preamp" in the second sentence, contrary to your title and your actual question.

    Interested in this whole cardboard-box thing. I do have a Little Smokey guitar amp which is just a board, 9V battery and 2" speaker in a cardboard Camel cigarette pack...
     
    wesonbass likes this.
  17. Wasnex

    Wasnex

    Dec 25, 2011
    The output of an instrument is typically "instrument level." The level required to drive most power amps is "line level," which is a lot stronger signal. A preamp typically takes and instrument or mic level signal and boosts it to line level. Some preamps may have instrument level outputs as they are designed to work with pedal boards, so check the specs.

    For best results, ensure input and output levels are compatible. You can drive a line level input with an instrument level signal but it won't get very loud.
     
    JRA, Float on man and SactoBass like this.
  18. FugaziBomb

    FugaziBomb

    Jun 5, 2017
    This sounds like a disaster. Please post video of the first time you plug it in.
     
  19. Float on man

    Float on man

    Mar 10, 2018
    Sorry typo, I meant as an amp preamp, should fix that. Thanks for telling me.
     
  20. Float on man

    Float on man

    Mar 10, 2018
    I understand that concern but I’m farely confident in my ability. I’m not going to make it a tube amp of sorts, I’m just making a tiny little thing I can use to record with. Nothing huge. No to mention, I’m only going to use it for like 30 minutes a week at most, and if it does catch on fire, I can quickly throw it into the street due to how lightweight it is. I’ll be fine, thanks for the concern though.

    So basically, that’s a yes but it’s not gonna be loud, right?
     

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