Midrange-forward pickups for fretless jazz bass?

[Iristone]

The volume knobs on this bass are just too touchy. I get a few mm of adjustment and then the pickup is off. I don't find it useful as a control. What has been useful is adjusting the pickup heights unequally, but I'm at the limit of what I can do there.

I'd also try the linear taper pots.
I also wonder if lowering a pickup helps? I think it's an electrical thing that you scoop mids when you connect both pickups in parallel, and the tiny serial resistance of the volume knob will break the interaction between coils and fix the scoop.

 

[paulraphael]

audio taper pots, right? two linear volumes are a nice way to appreciate the vvt flexibility.

How do you tell? They're what came with the bass.

 

[paulraphael]

Not necessarily. But with a VBT circuit you have an extra pot which adds additional resistance even when fully open. Higher resistance results in more highs coming through. So before I went through the expense and hassles of replacing pickups I’d first try upping the overall capacitance by either using a higher value tone cap or adding an additional low value cap to increase the load as was previously suggested. This won’t increase the mids per se. But it will lower the overall highs in relation to the mids so the mids will become more prominent.

Since a capacitor is the cheapest and easiest thing to experiment with, I’d start there. And I’d avoid opting for expensive so-called “tone” caps. Because it’s all just marketing hype. Regular polyfilm capacitors and ceramics work equally well and run under a dollar each. I’d next try experimenting with pot values if your bass has 500K pots rather than 250K. Only after I tried all that would I consider changing pickups unless I were still looking for a specific pickup sound. Chasing tone via pickup swapping can get expensive pretty fast.

General rule for a passive bass:

Lower capacitance and/or higher resistance = more highs

Higher capacitance and/or lower resistance = less highs.

It’s an inverse relationship. And you can juggle either or both measurements to better achieve the sound you’re after.

This article is a good read and goes into it in far more detail. Well worth checking out.

Final note: rather than putting yourself through the hassle of modding your bass, I’d like to strongly suggest getting yourself a graphic equalizer pedal first. That will let you sculpt virtually any sound you can get by modding your bass plus a whole lot more sound options. It doesn’t need to be an expensive EQ either. Behringer’s BEQ-700 bass graphic equalizer will only set you back $25. You may want to opt for a more feature rich EQ pedal later on. But for dialing in a specific tone you’re after, even the most basic graphic EQs will get the job done easily .

So before you do any modding, I recommend making a graphic EQ pedal your first port of call.

Great information, thank you.

How does a change in resistance make a tonal difference when the bass is plugged into a mega-ohm amp input?

 

[Aloe]

How do you tell? They're what came with the bass.

usually there're some letters and digits on them. like a250k (audio taper, 250k) or b500k (linear taper, 500k). some cts pots might have more obscure codes that need to be looked up to see, what's it exactly.

my guess was from my experience, two audio volume pots indeed should work like that. but with two linear pots it's a totally another story.

 

[LowendG]

If it doesn't need to be hum-cancelling, then my faves are actually the Fender Pure Vintage 74's. They are punchy, just a little aggressive, and to my ears have a great midrange focus but not at all wooly--they just sound..."classic". On my 70's style Jazz with both pickups dimed it doesn't come off as "scooped" really at all, it's very focused and speaks clearly in a mix (none of that disappearing act). In fact I examined the EQ profile of it in my DAW compared to one of my P's and they were almost the same, the J just had a little more low lows.

 

[paulraphael]

usually there're some letters and digits on them. like a250k (audio taper, 250k) or b500k (linear taper, 500k). some cts pots might have more obscure codes that need to be looked up to see, what's it exactly.

my guess was from my experience, two audio volume pots indeed should work like that. but with two linear pots it's a totally another story.

Cool, thanks. All 3 are marked M250 KΩA, which I assume means audio.
The tone pot is also marked 36C; the volume pots 39C. In case that means anything.

 

[ColinR]

I can get pretty killer fretless tones out of Aguilar pickups (or Barts) and round wound D'Addario strings. Roll the front pick up off a bit and boost the mids if needed, depending on the bass.

 

[40Hz]

Great information, thank you.

How does a change in resistance make a tonal difference when the bass is plugged into a mega-ohm amp input?

A passive guitar tonestack is a second order low pass filter. Which means it allows low frequencies to remain mostly unaffected while the higher frequencies get attenuated. By changing the overall resistance and/or capacitance of the circuit you change its inductance. This affects the resonance (basically the overtones) and roll off frequency response of the filter. And this is pretty much where what we call the “tone” or “character” of the circuit is determined.

On a guitar amp you get the most efficient signal transfer when the input signal most closely matches the input impedance of the preamp stage. A guitar cable has both resistance and capacitance. This gets added to that of your bass’s circuitry and can be thought of as basically another tone control except it’s settings are fixed by the electrical characteristics of the cable itself. The longer the cable the greater the effect. The newer more expensive cables use wire engineered to have as little an impact as possible. But every cable will still put some load on the input. Which is why buffering circuits are sometimes added to minimize the muffling effect of long signal chains before they hit the input jack on your amp.

Fortunately, instruments amps are already designed to deal with that issue. And most of us are so used to a cable’s effect on our sound that something can sometimes sound off to us if it’s not there. Which is why you’ll find wireless guitar rigs sometimes include a switch that lets them simulate the effect of a guitar cable on the signal if so desired.

If you have questions about amps however, your best bet is to go over to the Amp and Cabs area of TB and ask your questions there. You’ll likely wind up with the real amp experts like Wasnex and AgedHorse, along with the other electronics gurus joining in to give you much better and far more accurate answers than an amateur like me ever could hope to.

 

[paulraphael]

I've been looking at Helmuthe Lemme's article. From what I understand, changes in resistance affect the size of the resonant peak; changes in capacitance affect both the size and frequency of the peak, and the shape of the slope.

If someone were to get some relatively dark/fat sounding pickups (Area Js, or Nordstrand N4JSE) and found them too heavy sounding, to what degree could this be adjusted by moving from 250K to 500K volume pots? I understand graphically that it would just increase the (very high mid) peak a bit. Sonically, would this risk giving the pickup more of a scooped sound, or would it just balance it and open it up a bit?

 

[40Hz]

Higher resistance makes for a brighter sound, which is why humbuckers mostly are paired with 500K pots. However, Gibson also uses 300K pots on some of their basses that have sidewinder pickups which are brighter sounding than humbuckers, but not as bright as single coils despite sidewinders being a type of humbucker.

You can also add a small value resistor between the hot leg of a pickup and the volume pot, which will alter the transfer characteristics of your pickup. Some builders even use a small trimmer instead of a fixed resistor for that purpose or go with a treble bleed mod to the volume pot that helps maintain the overall brightness of a pickup by allowing more highs to “bleed” through as you lower the volume knob.

There’s also the option to use a choke coil circuit that can further effect the tone a different way than the tone pot and cap can by itself. The choke can also be combined a switch selectable bank of different value capacitors to create the classic Gibson Varitone circuit found in some of their guitars. Or you can leave the coil out and just have a capacitor switcher like you’d find in a Tonestyler.

Then there’s all the variod pickup switching schemes to experiment with: series, parallel, out and half out of phase, along with coil tapping and coil splitting. And also the positioning of your pickups in relation to the bridge.

Bottom line: there’s a lot you can do with a passive bass to sculpt its sound. No batteries required.

 

[sunbeast]

Cool, thanks. All 3 are marked M250 KΩA, which I assume means audio.
The tone pot is also marked 36C; the volume pots 39C. In case that means anything.

The volume pots put in almost all production basses are Audio/Log taper, which is unfortunate for a dual-volume setup. Linear taper pots are better for dual-volumes IMO as they are easier to get more nuanced blends of the pickups. I agree with others that being able to turn down one of the pickups just a bit should give you what you need- I usually turn both pickups up full, then start rolling one down til I hear the mids and punch start to pop out. I do this on both Jazz Basses and Rickenbacker as I find both pickups on full is always too mid-scooped and soft for my taste

 

[paulraphael]

The volume pots put in almost all production basses are Audio/Log taper, which is unfortunate for a dual-volume setup. Linear taper pots are better for dual-volumes IMO as they are easier to get more nuanced blends of the pickups. I agree with others that being able to turn down one of the pickups just a bit should give you what you need- I usually turn both pickups up full, then start rolling one down til I hear the mids and punch start to pop out. I do this on both Jazz Basses and Rickenbacker as I find both pickups on full is always too mid-scooped and soft for my taste

I think this is the path I'll take. Replace the pickups with hum-cancelling ones, and the volume pots with linear tapers.

 

[Jazz Ad]

Dimarzio Model J is your answer.

Indeed. Another great choice for midrangy fretless is Bartolini Original series. They have avery mellowy tone, almost like a built-in phaser that works wonderfully with fretless.

 

[Yahboy]

(DiMarzios diagrams)
Model J:
View attachment 7037568

Area J:
View attachment 7037569

A glance at this suggests I'd like the Area J more, but it depends on how Dimarzio defines low mids and high mids. In bass I think of high mids as ~800hz, but I believe audio engineers think of it as more like 2khz +.

To my ears the model J's (on YouTube, for whatever it's worth) sound fat and low-mid heavy.

Once you install a 500K volume pot for Model J , i sure you will liking with it.

 

[klattman]

I went with the nordstrands on my fretless. They are thick but the bridge pickup has the most kid growl I’ve heard.

I also installed a John east 3 preamp so I can adjust to almost anything from there.

Other option is to first try 75% bridge 25% neck, roll off tone some and see if that helps.

 

[togril]

just saying, but Warwick once had done a jazz bass with a passive tone and a passive bass cut. cutting the bass and treble was the way to emphasize mids.

this said, the first thing I'd try is the amp's EQ.

I recently got an early 1990s MIJ fretless jazz bass, which I've shielded and restringed and set up. It's sounding quite close to what I'm after. I go for a sound (with both pickups on) that has a lot of midrange presence, especially in upper mids (around 800 hz). I don't need a lot of high end (I don't slap, and and don't like string noise) but I also don't want the dead and thuddy sound of old-school flats. I don't need huge, extended bass. My lows are more about tight and punchy upper bass. Which is all to say, I'm not into any kind of scooped sound or extra extended frequency response. I'm not looking for much more lower mids ... if I need those I just solo the neck pickup.

In a sense, I'm trying to undo the little scoop you get from blending the 2 J-pickups.

Right now I'm using D'Addario nylon tapewounds (which I fell in love with at a music store) and am getting close to the sound I want by lowering the neck pickup as far as possible, and bringing the bridge pickup very close to the strings. I've also tilted the pickups, so the bridge pickup is closest to the E string and the neck pickup is closest to the G string.

With this arrangement, the bass sounds great soloed, but I'd like to be able to get a bit more mid emphasis when playing in a mix. I've tweaked the pickup heights as much as is practical. Soloing the bridge pickup is an option for some things but is too much most of the time. These are the stock (probably Japanese) Fender pickups.

Would aftermarket pickups make sense here? If so, any particular recommendations? I'm leaning heavily toward hum-cancelling pickups, since I don't need the most open highs.

I've listened to a bunch online but don't know how trustworthy this is, since most demos are with very different strings and fretted instruments.

The Nordstrand NJ4SEs seem interesting. I'm worried that they might be too thick sounding, since they seem to emphasize the low mids.
The NJ4SVs sound quite good also.
DiMarzio Area Js might be an option.
What about something like the Fralin split coils, with a bit of overwind on the bridge?
Something else I haven't thought of?
Or should I just count my blessings and stop shopping?

Perhaps it could be easier / worth looking at a SIMPLE eq system, boosting mids or cutting bass. Etc. If you are concerned about drilling holes, then perhaps stacked pots. Otherwise Warwick MEC’s,
But I really think an eq system (active would be the most effective solution, because it gives you much finer control. What sounds good on another bass may not translate the same on yours….(yes! I am one of THEM!)
what is the fretboard material?

 

[paulraphael]

Just want to report back that I made a final decision and the surgery was a success. I went with Nordstrand NJ4SVs (based on listening to samples and some discussion with the guys at Nordstrand). I got a deal on the pickups.

The more significant change was switching the volume pots to linear taper. Before, I was trying to get the tone I want by varying the pickup heights. But I'd taken that as far as it could go. Now I can just back off the neck pickup 1/8 turn and it's done.

I went ahead and replaced the jack and the tone pot and cap, just because it was all 30 years old, and why not. In doing so I discovered that either my old tone cap or pot had gone bad. The effect of turning down the tone control had been too subtle. Like only audible at all under some circumstances. Now the control works exactly as expected. The new parts are the same values as the old ones.

Thank you everyone for the advice. I'm quite happy. The bass is now completely noise-free, and I can easily dial in tones that I couldn't before. Including ones I've been looking for.

Also big thanks to Youtube for teaching me how to solder. This was my first project. The joints came out better than expected ... although I don't think NASA will be knocking at the door with job offer any time soon.