Bartolini / Modulus mods for better tone

Discussion in 'Pickups & Electronics [BG]' started by LP75, Dec 7, 2007.

  1. LP75


    Aug 29, 2006
    I thought I should write my story here just in case anyone else has a similar situation.
    In April '07 I took delivery of a new Modulus Quantum 5 with the Bartolini pickup and Bartolini NTMB (3-band) system. The bass was ordered with a special burl myrtle top, and the construction is flawless, beautiful.

    But I had a problem - every time I played it at a gig or a rehearsal, I found myself constantly adjusting every possible parameter to get the sound I wanted to hear - that big, full, clean and clear Modulus Voice - yet I could not get it dialed in. The middle and high-mid frequencies were missing. I knew my amp rig wasn't the problem as my other basses all sung beautifully through it. I was convinced this problem was with the Bartolini system.
    I read a few columns here in talkbass concerning "Dark, Muffled" sounding Bartolini systems, and I saw the same comments many times. Although my bass had powerful lows, and a high sizzle with the treble on full, it was
    sounding "pinched" or rstricted somehow, the high mids were missing, and the dark, deep tones were overly dominant.

    Then I remembered that my regular guitar guy (for the past 20 years) here in my hometown of Bellevue WA - Mike Lull - is an expert in Bartolini electronics. I took my bass to his shop one week ago, and he immediately popped off the control cavity cover, and explained what needed to be done.

    The 25k Volume and pickup Blend pots were changed to 500k value pots (and the Volume was changed to a pull-out passive type). He then installed a 3-way switch that selects Mid control center values of 250Hz / 500Hz / 800Hz pre-wired by Bartolini. I also had him replace the stock stacked Treble/Bass knob with one that has a top that matches the other knobs - personal preference.

    These changes opened up the tone like I could barely believe! The bass now has a rich, round, ringing Voice that speaks evenly across the frequency spectrum, and across the fretboard. I thought I had made an error by selecting Bartolinis as most everyone advised me to do. Maybe the EMG system would have better suited my tastes, as I love a bright, snappy definition when I play with a pick for rock music. But after those simple mods, I have a tone that I suspect is even better than the EMG system. This thing is just incredible now.

    Anyone having "Dark, Muffled" problems with your Bartolinis would do well to look into your Volume, Blend or Tone pot values, and consult with an expert on how to select matching values. I am lucky to have Mike Lull 5 minutes from my home, and Bass Northwest about 20 minutes away in downtown Seattle. My next new bass *will* be a Mike Lull. I can hardly wait to save up the money....

  2. BruceWane


    Oct 31, 2002
    Houston, TX
    That would certainly make a big difference - as fas as I know, 25K pots are only used with active pickups - EMG's, a few Seymour Duncan models, and very few Bartolinis (active Barts are custom order only, so they're pretty rare).

    Sounds like the folks at Modulus probably made a mistake and used pots intended for an EMG equipped bass.
  3. DavidRavenMoon

    DavidRavenMoon Inactive

    Oct 20, 2004
    I was just about to say that. Did you mean 250K?
  4. LP75


    Aug 29, 2006
    No - They were 25k pots. Mike Lull said to me that they would have been better matched to the EMG pickups, and were wrong for the Barts.
    I have wondered if Modulus always uses the same 25k pots, or if they DID make a mistake. If they did, then I had to spend extra money to fix their error.

  5. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA I'll have to pop the back off my Genesis to see what's brewing. I love the idea of adding a mid-select switch to the existing Bart harness. Any idea what part # Mike used when ordering / installing?

  6. DavidRavenMoon

    DavidRavenMoon Inactive

    Oct 20, 2004
    That HAD to be an error. 25K is the value for EMG's. Barts generally use 250K. I would think they would know better.

    Mike Lull knows his stuff, that's for sure.
  7. maurilio

    maurilio Guest

    May 25, 2003
    If the original Vol pot was wired only direct as volume and no passive/active switch, the 25k is correct.
    The Blend 25k for Bartolini pups is indeed wrong. Originally it's 250k.
    Seems like that bass was meant to have EMG and they changed it to Bart and forgot to correct the blend.

    I've compared the two different value (250k/500k) on the blend pot with Bartolini pups, but the difference is minimal.... still, 25k it is absolutely wrong for passive pups. No wonder your bass was dark and muddy!

    Glad you solved the issue... I like Bart on Modulus.


    BTW, what I like to do with Bart pres is to change the capacitor on the mid switch to shift the high/mid freq from 800hz to 1000hz (like MTD). It gives a nice cut (better for me) for slap!
  8. LP75


    Aug 29, 2006
    I found this:

    The whole wiring harness. And it looks like I made a mistake - maurilio is right - the blend pot was 250k.

    Also, I spoke with Anderson at Modulus today, and he confirmed that they install the wiring harness as it comes from Bartolini. So it is Bartolini that selects these values.
    I sure do like my Q5 100% more now. I played on it for a few hours this evening, and just swooned over the tone - it's like I have dreamed for so long.

    Now all I need is a few Meyer 2X18" powered subs... One for each side of the drummer....

  9. wmheilma


    Jan 5, 2010
    Anyone out there figured out what parts to use for custom voicing on the old TBT or TBIBT Bartolini on board preamps? Long ago there were parts in one of my basses that made it too bright, so I called Bartolini and got recommendation to pull out a cap and resistor and start 'stock' with the TBT. Recently, I decided to brighten the tone by puttting the parts back in. But I lost them. Oops. I found some info on the Bart site, but it is pretty slim as to what parts have what effect for the grey and white wires on the old TBT. So I guessed... We'll see how that goes this weekend :)

    BTW- I'll have to look in my Modulus, but it has Barts and has always had an amazing singing quality! The voicing mod is on a different and much older bass.
  10. Ballin'bass


    Jun 16, 2014
    Madison, WI
    Anybody ever try John east preamp in their modulus? I have one in my vj4 and it sounds unbelievable. Having a quality sweepable midrange is so awesome for tone sculpting. Though they are a bit pricey:greedy:...
  11. Bob_Ross

    Bob_Ross Gold Supporting Member

    Dec 29, 2012
    I have an East EQ-02 in my Modulus 6-string. Really fabulous combination! Not only is the East an astonishingly versatile tone shaper, but for whatever reason when I open up both filters completely (effectively taking them out of the circuit) the bass still sounds better than it ever did with its previous preamp's tone controls set to their detents.

    That being said, I just installed a Bartolini NTMB preamp in another bass last night (a Warmoth with a single Bartolini MV52CBJD quad-coil humbucker in the MusicMan spot) and holy crap is that a nice sounding combo!
    Ballin'bass likes this.
  12. Crusty333


    May 14, 2007
    Digging up the past, I know. Just wanted to share my similar story. I have had a '98 Modulus Flea 5 for close to 15 years. Appears to have a Lane Poor pickup. The sound was much better than the starter bass it was replacing, so I didn't hear anything wrong when I was trying it out. As my tastes changed I kept finding it lacking in tone and overall life. Changed the pre and it changed the sound a bit but still didn't solve the problem. I finally demoted it to a backup and didn't put much more thought into it. Fast forward 10 years or so and the volume pot finally crapped out. Pulled it out to replace it and there it was... an a25k volume pot. Apparently I had never looked at it in all of my messing around in the control cavity. I put a spare a500k in to test while I wait on the correct format pot to ship and the difference is incredible. That $2 part cost me thousands of dollars in tone hunting over the years. Lesson learned... better late than never.
    Clark Dark likes this.
  13. Clark Dark

    Clark Dark

    Mar 3, 2005
    Seems that pot value comes standard with that Bart pre. Info worth sharing.:cool:
  14. phillybass101


    Jan 12, 2011
    Artist, Trickfish Amplification Bartolini Emerging Artist, MTD Kingston Emerging Artist. Artist, Tsunami Cables
    The Dark Muffled sound is old news. Get the Bart Classic Series. The problem is Bart makes so many kinds of Pups people don't know what to order. I stay with the Classic or Bright sounding Bart Pups. Not that I'm biased or anything.
    Ballin'bass likes this.