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Help needed with a passive bass through my rig.

Discussion in 'Amps and Cabs [BG]' started by Visirale, Sep 10, 2008.


  1. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    I got an Epiphone thunderbird to thrash around as a gigging axe with my band. I love the tone of it! It's right up my alley. I played it at GC through an SVT4 and an 810, and an SVT-CL through a 610. Both gave me tons of clean headroom.

    When I got home and plugged in to the Titan, the clean headroom wasn't there. I tried it without the pad first. I had to turn everything up to pretty high gains to get volume, but as you all may know, the more you turn up the gain on the titan, the less clean it gets. With all my active basses, I have clean headroom for DAYS. With the thunderbird, it's just a big distorted mess. The active pad didn't help much either...

    My initial thoughts are to get some kind of a clean boost or an outboard pre of some kind. That should make things better, right? I'll have a hotter signal and won't have to drive the amp as much. Is it as simple as that? I'm not too sure about that because I know guitarists use clean boosts to get more drive from their amps...

    Any ideas from you guys?

    Thanks!
     
  2. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    If using active basses with the Titan results in great sound, then that's pretty much the same as using a passive bass through an external preamp (clean boost). Of course it will depend a bit on the specific bass and preamp, but the idea stands.

    FWIW The Radial PB1 is my choice for this application- clean and strong, doesn't alter the tone of my bass.
     
  3. I use a Sansamp BDDI to heat the signal up before going into the amp. It gives me my tone with very little effort with a passive bass. My sound is crap without it.
     
  4. mrkreuzschlitz

    mrkreuzschlitz

    Jun 30, 2008
    Dacula, GA
    If you do the Sansamp, be sure to turn the blend knob all the way down if you want CLEAN BOOST.

    Otherwise, I've heard the BBE Boosta Grande is pretty bueno! :p
     
  5. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    Thanks guys. I've had the sansamp before and was not a fan.

    I LOVED the class a boost on my Avalon U5... any pedals have class A boost?
     
  6. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Why yes, the Radial PB1 does! :p It's the only one in pedal form that I know of right now.
     
  7. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    Well that gets an easy move to the top of my list then. I'm not about to shell out $500 for another Avalon, haha.

    Also, I know I've read something on here before. Some sort of circuit that can be added to a passive bass to bring up the output to something closer to an active bass. Not a preamp, because there are no tone controls... just an onboard clean boost. Does this ring any bells for anyone? I've been searching for a good hour and can't find anything. Obviously, a battery is involved... This would be good for me because it'd be one less thing to have to carry to gigs!
     
  8. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
  9. EMG makes two items that will meet your needs. The EMG-PA2 and The EMG-AB

    Don't be fooled by the marketing. They are catering to g@#$@r players that want a clean boost to overdrive their tube amps. I had the PA-2. It is very transparant and able to drive a power amp on its own! I own a U5 so I have a good point of reference.
     
  10. Of course, you would never want to pad down the input of a low output bass. That's moving in the wrong direction.

    Theoretically, a weak output bass (like some passive basses) with the gain turned up to compensate should present an identical signal to the preamp as a high output bass with the gain turned down. I guess input impedance could have an impact, but that's typically minor, and most amps and preamps designed for bass have an input impedance within the range to work well with active and passive instruments.

    My guess is, that the 'woofiness' you are hearing is a result of the pickups of the bass (that's not necessarily a hi fi instrument) and possibly a more low mid/upper bass sort of thing coming out of that particulary bass.

    My guess is, a preamp won't really help that much, since again, providing a hotter signal to the preamp with the pregain reduced shouldn't sound that different from a weak signal with the gain knob cranked a bit more. That's what the gain knob is for!
     
  11. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    Well, it wasn't "woofiness" it was all out overdrive. I was having to set the pre gain past noon which makes for a lot of "bloom" on the mesa. If I set the pre gain to under noon, and adjusted the master, I'd have to crank that which has a similar effect.

    And I definitely understand that it is not a hifi bass--about the opposite of my M5-24.

    I went to Bass Central today and reserved the last of the Aguilar Tone Hammers coming in this Tuesday. In an ideal situation I'd like to make the thunderbird active, but don't want to modify it or the knob layout, so this will effectively give me an OBP-3, just outboard instead of onboard. Hopefully it works. If not, I'll be able to flip it pretty quickly.
     
  12. Juniorkimbrough

    Juniorkimbrough

    Mar 22, 2005
    Mississippi / Memphis, TN
    Endorsing Artist: Lakland Basses
    If turning the gain knob up is causing overdrive it seems like it would be sending a hot enough signal. I may be incorrect but I thought the gain + how hot your output on the bass is what caused the overdrive?
     
  13. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    I'm just speculating here, but it is possible that the input gain control on the amp is not "just" a control over the level of the signal going into the preamp tube, but may change other factors in the circuit which induce distortion exponentially; while simply increasing the input level is more linear. Again, just a thought, puzzling it out.
     
  14. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    Yes, I thought I had established that.

    The titan's gain works like this... It's clean up until noon. Then from noon - 3 oclock it get's exponentially more tubey. Everything past 3 is all out overdrive.

    I was having to boost the gain up into those areas in order to get the volume I needed, a problem I don't have with my active basses.

    Sorry if I wasn't being clear.
     
  15. kraigo

    kraigo

    Jun 21, 2007
    Minneapolis, MN
    My first thought was a Sans Amp BDDI, which I've got but don't really love. As long as you keep the blend low it's serviceable. I sold it once and bought it back for $25 less than I sold it for. I may sell it again.

    David Raven Moon sells a "colorless" on board preamp, BTW. http://www.sgd-lutherie.com

    Hmmm - maybe the Sans Amp BDDI needs to go back into my "sell" pile. On the one hand I can't really see ever using it again. On the other hand it's the only small DI box I have.

    KO
     
  16. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    That's not 100% clear yet. For one thing, not all active basses have high output. Yours might, but I wouldn't assume it just based on what you've said so far. For another, if they do have high output, then why are they not causing overdrive? Right now what I described is more of a wild stab than an established fact.

    Other possibilities off the top of my head: It could be the impedance relationship between the bass and the amp, as Ken suggested; or it could be that the frequency profile of the active basses emphasizes a range that projects better at lower gain compared to the frequency profile of the T-bird.
     
  17. Nothing you said there surprises me. Most amplified circuits are much cleaner and have lower distortion in the lower half of their gain range. Once you turn up past a certain point which varies, distortion and other changes creep into the sound.

    If you do some of your boosting with a preamp - and keep it in its clean range - and then follow up with the amp - you should be able to keep the sound more the way you want it.

    But I'll also point out - you say the sound gets more "tubey" with more gain, and that's generally a desirable thing. Tube sound is generally thought to be more desirable.
     
  18. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    Yes, most amps do. The Titan however is really designed to emulate a tube amp... more so than just a normal hybrid head. From nil until 10 oclock it is just a normal clean solid state sound. Then from 10 til noon it's a warmer solid state sound, typical hybrid sound. From noon on, it's all out tube. I usually like to keep it at or slightly past noon. It does a great job of emulating a clean-ish tube amp, breaking up when I dig in a little harder.

    I do like tubey, but I also like clean tubey more than all out dirty tubey. But luckily I have 1200 watts of headroom to play around with to keep it as clean as I like.

    Glad to hear you think the pre is going to work... I have my fingers crossed.
     
  19. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    The titan has 3 gain stages. Gain, master, and "output" and it makes 1200 watts. Turn the gain back down and turn up whichever of master/output has a lower setting. You should be able to get that head loud with the gain on "2" by cranking the later stages.
     
  20. Visirale

    Visirale

    Mar 23, 2003
    Orlando
    I had them all close to dimed... I know the head is fine because it is loud as hell with my other basses... man this is frustrating...
     

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