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Onboard preamp frequencies

Discussion in 'Pickups & Electronics [BG]' started by Lorenzini, Jan 3, 2016.


  1. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Other than Mike Pope Flexcore, does anyone know of an onboard preamp that does 80hz, sweepable mid, and 6k-10k treble?

    Bartolini does 30hz Bass (really???), nice mid selectors, and a 10K Treble.

    Nordstrand is close except for a 4K Treble, too low for my liking.

    Noll is similar, but they DO that 80hz Bass.



    Just making conversation.

    But really, Bartolini at 30hz? Is the shelf just not hard, so it grabs a bit above? Because 30hz is realllllly low.
     
    QuickNasty likes this.
  2. Yeah those are strange specs. Which bart pre are you refering to? I didn't know they had a sweep mid preamp. I usually design a roll-off from 30Hz down with my stuff. Cranking those kind of frequencies can really reduce the efficiency of your amp/speakers, or even damage them. Especially if you like to slap.

    Yeah, I'd say it's a fairly gentle slope. Probably 3dB/octave. So if they quote say, +/- 16dB at 30hz, then with the bass control maxed, you are still getting 13dB boost at 60hZ, 10dB at 120hz, etc etc.
     
  3. JustForSport

    JustForSport

    Nov 17, 2011
    It's low for an E, but not for a B.

    80hz is near an octave up from low E?
     
  4. The Aguilar OBP-3 is listed at 40 hz but in reality when you look at it on an analyzer (which I haven't done for quite some time, so I don't recall specifics) it significantly affects frequencies Much higher. Certainly over 100.
     
  5. Bob_Ross

    Bob_Ross Supporting Member

    Dec 29, 2012
    I would bet it's 6dB/octave, because that's more typical of a shelving type tone control...but that's still relatively shallow as far as filter slopes go. In general, for the kind of tonal shaping that you want on an instrument's "Bass" (or "Treble") controls, shallow shelving curves are more desireable than steep ones because you don't so much want to accentuate the corner frequency (or even necessarily Only-Stuff-Below-The-Corner-Frequency) so much as you want to grab a broadband hunk of Everything-In-The-General-Neighborhood-Of-The Corner-Frequency. It's painting with a broad brush...which is why we call them "Bass" (or "Treble") controls rather than use more specific, distinctive names for their respective registers.

    tl;dr -- 30Hz w/ a shallow shelving curve is what you want if you want to be able to turn up/down the "Bass" on your bass.
     
    Last edited: Jan 4, 2016
    ctmullins likes this.
  6. QuickNasty

    QuickNasty

    Jul 29, 2012
    I tend to do miniscule cutting with an onboard preamp.

    I enjoy lower and higher eq frequencies like what the aguilar obp3 offers.

    I use them for cutting the edge off of the lows and highs. Really does a great job of tightening up the tone.

    Mind you that I use very very small turns of the pot, but it really helps.

    LPF & HPF of sorts.

    To answer your question, the John East uni-pre may be what you're looking for.
    UNI-PRE 3 Knob (U-Retro Upgrade with Expanded Feature Set, Same Price!) - BASS
    It allows you to set whichever frequency you need for highs and lows via an internal trim pot. Also has sweepable mids, plus a push-pull bright switch to get even more high-end response.
     
    Last edited: Jan 4, 2016
  7. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    That East pre looks really cool...

    I personally like to be able to adjust my own frequencies. Every bass is different and responds differently to different frequencies, so the ability to adjust it seems like a no brainer.

    Thanks for all of the feedback ya'll
     
  8. maurilio

    maurilio Musician - Owner Mo's Shop & MBD - Tech Nordstrand

    May 25, 2003
    Redlands, CA
    most of the preamps around can be modified…. Nordstrand as well…. add different caps to the treble ctrl and the freq will change...
     
  9. J.Wolf

    J.Wolf Gear Reviewer - Bass Musician Magazine Supporting Member

    Apr 29, 2003
    Asheville, NC
    I was just gonna suggest the uni pre-

    internally adjustable:
    -bass and treble frequency points.
    -pickup blend
    -output
    -range of midrange sweep for semi parametric midrange control
    -flat response or classic J retro built in EQ curve

    Plus it sounds REALLY good. no kidding
     
  10. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Is this relatively simple to request and execute upon purchase?

    I love Nordy stuff...
     
  11. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Internally adjustable is the part that really intrigues me. That flexibility.

    Is there a graph of the J Retro EQ curve?
     
  12. J.Wolf

    J.Wolf Gear Reviewer - Bass Musician Magazine Supporting Member

    Apr 29, 2003
    Asheville, NC
    Good question. I've not seen a graph depicting exactly what's going on with the 'j retro curve'. I will say, based on experience that at the very least, theres an upper midrange bump that fills in nicely for basses that have a natural dip there, as many seem to.

    If you go on the east site, there's an excellent pdf that shows all of the features and layout of the uni pre controls. I can't figure out why they're not more widely used yet, considering how excellent they sound and flexible they are.
     
  13. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Good question. I personally went with an Audere because I heard that it was a bit of a flatter response. However, now I have added an SB5000 my roster and feel that it could benefit from a tastefully exaggerated preamp.
     
    Mr_O'B likes this.
  14. J.Wolf

    J.Wolf Gear Reviewer - Bass Musician Magazine Supporting Member

    Apr 29, 2003
    Asheville, NC
    I had an early Audere (not sure how much they've evolved) but I liked it quite a bit. It was however pretty subtle in its effect, compared to the Uni-pre, which in its extreme settings is mega powerful. i find that I mostly use fractional turns of the knobs to get desired effect.
     
  15. maurilio

    maurilio Musician - Owner Mo's Shop & MBD - Tech Nordstrand

    May 25, 2003
    Redlands, CA
    Hi,
    very easy…. it's just a simple cap soldered to the pot

    23635026034_f5f6f16eb9_c.
     
    Last edited: Jan 8, 2016
    Spfairchild and 4StringTheorist like this.
  16. 4StringTheorist

    4StringTheorist Supporting Member

    Nice! This was not mentioned in the documents that came with my 3b. What are the cap values for various knee frequencies?
     
  17. maurilio

    maurilio Musician - Owner Mo's Shop & MBD - Tech Nordstrand

    May 25, 2003
    Redlands, CA
    because it is not an official mod… but like any electronic devise it can be modified. I don't have any number, to me if it sounds good it's good :)
    in the picture the cap is for a modified higher freq boost, if installed on the middle lug it will affect both boost and cut….
     
  18. 4StringTheorist

    4StringTheorist Supporting Member

    Interesting! I love the default value for boost, but would love to drop the cut frequency down considerably to more closely emulate a passive tone rolloff.

    Sounds like I can only increase the frequency above the default if I add capacitance, based on your statement. Am I right in that evaluation?
     
  19. maurilio

    maurilio Musician - Owner Mo's Shop & MBD - Tech Nordstrand

    May 25, 2003
    Redlands, CA
    than you need the delano hybrid pot 50k/250k:
    Potentiometers - Pots | Jacks | Switches | Shielding
    because an active treble ctrl cut will never sound/act like a passive tone ;)
     
  20. 4StringTheorist

    4StringTheorist Supporting Member

    No, that's not at all what I'm talking about doing.

    I never said I wanted something identical. I used the words "more closely emulate," so I'm not looking for verisimilitude.

    I'm guessing your reply means that there's no cap configuration I can apply to those three treble wires that reduces rather than increases the knee frequency of the treble control?
     

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