Noiseless J bass pick up quandary and advise

[skipper01]

Hi, I recently bought a s/h Sandberg Marlowe DK bass (mk1) that is passive with 2 standard jazz style pickups/positions.
It’s essentially a jazz bass but to me sounds a bit ‘darker’ and ‘meatier’ than I expected. It has the standard 2 volumes and master tone.
I bought it for home recording exclusively.
Regrettably, it turns out through exploration I live in a high RF area and noise/hum is a real problem.
My friends single coil strat guitar is very subject to the same hum but Les Paul humbuckers are fine.
The Sandberg is basically realistically only useable with both pick ups on which I understand creates a split coil scenario.
I can see it has been screened around the control cavity as I can see the paint. I don’t think that is the issue.
Anyways, I actually like the sound of just the neck pick-up on and it’s kinda pointless having a guitar that I’m then limited in use sonically.
So, I’m sad to either have to sell it on to get some like ie a Precision or to replace the pick ups with noiseless ones.
I’d rather consider the later at present.
In terms of the noiseless pickups it seems a bit of a shot in the dark other than listening to demos on YouTube etc that is tricky.
I’m guessing noiseless pickups are inherently going to fairly dramatically change the tone of the instrument so I suppose I just have to take a punt on something?
However - Can anybody recommend or suggest anything maybe through their own experience?

[Wonks]

I fitted two humbucking Bartollini J-Bass pickups into a Yamaha BB604 as the original single coils were very prone to picking up hum. Sounded great to me and better than the originals. It did have an active preamp, so the sound from them is going to be slightly different to that from a purely passive system. I think I got them used from eBay, so they didn't cost too much. Whether they'll sound exactly like standard J-bass pickups I can't say, but purely as pickups, they sounded good.

But I would investigate the screening a bit more. A lot of time cavities may have screening paint in, but remain unconnected to ground. This makes the screening all but useless, so it's worth checking continuity to ground of the paint to the ground on the output jack.

Also check if there's copper or aluminium foil on the underside of the pickguard and if so, whether there's a ground connection for that at all. It's common to see nicely foil or paint screened control and cavities, but with no extension onto the top of the guitar to make contact with grounded control plates or undersides of pickguards.

Shielding will never make a single pickup guitar as silent as a humbucker equipped guitar, but it can cut down the noise to an acceptable level.

[ef37a]

Hi Skipper, guitars and basses pickup hum in two distinct modes. Electro-magnetic
and electro-static.

The first process is the fundamental way pups 'read' the strings so the only way to beat external magnetic hum fields is with a humbucking pickup. However, electro-static noise can be greatly reduced by screening. You can actually enclose the whole pickup in foil and it will still work. So, how to tell the difference?

E-magnetic pickup will have a strong directional component, as you rotate and translate the bass 'in space' the hum will go into maxima and minima. E static pickup is not nearly so position sensitive. (of course, Sod's Law dictates that lowest level of EMag hum occurs in a position which make the bass impossible to play!)

So, careful screening and grounding of the screen can often give several dBs of noise reduction. Also make sure the bridge and hence the strings are also grounded. If you don't want to go for humbuckers you might have some luck with a 'parasitic' bucking coil? This should be as close to the active coil in terms of size, shape, inductance* and resistance but not contain any magnetic material and it injects hum pickup in anti-phase to that from the active pup.

I am sure Zen will be along shortly with some practical suggestions.

*If there is no ferrous material in the coil then of course inductance will be lower.

[Sam Spoons]

Fender do noiseless JB pickups which they say "Fender Vintage Noiseless Jazz Bass pickups produce all the brilliant clarity, definition and harmonic attributes of a vintage Jazz Bass without the hum. Maintain the legendary tone of a vintage Jazz Bass with the added bonus of modern circuitry."

https://www.fender.com/en-GB/accessorie ... 02000.html

[ef37a]

Fender do noisledd JB pickups which they say "Fender Vintage Noiseless Jazz Bass pickups produce all the brilliant clarity, definition and harmonic attributes of a vintage Jazz Bass without the hum. Maintain the legendary tone of a vintage Jazz Bass with the added bonus of modern circuitry."

https://www.fender.com/en-GB/accessorie ... 02000.html

That might seem expensive but my recent searches for the single split P bass pup showed them to be over £100 and some 'exotics' nearly twice that.
For two pickups and no hum? Bargain.

Dave.

[Funkyflash5]

In a bit more upscale option, Nordstrand make 3 models of noiseless J-pickups, ranging from classic j-bass bright, through darker and meatier, to p-bass in a J-shell. And they are willing to do custom if you like, although I don't know what the cost of that might be!

[skipper01]

Many thanks for the replies, help and advise.
The hum/noise is somewhat position dependent so from the info supplied (thanks again for this ef37a) it is electro magnetic in nature.
Yes, as highlighted, its a real drag having to find the place/angle where it is 'usable' in terms of the hum/buzz that is not practical going forward.
I can only confirm the control cavity is screened using the paint and the grounding lead disappears into the hole that feeds the pickups.
I dont know about the pickup and bridge screening.
I think my only option is the noiseless pick-up change/upgrade.

Out of interest, I wonder why my room/house/area is so heavy in terms of electro magnetic interference?
I was told it could be related to RF noise due to the close proximity to a large transmitter....
Cheers again

[Wonks]

Hi Skipper, guitars and basses pickup hum in two distinct modes. Electro-magnetic and electro-static.

I think you're using the wrong term with electrostatic here, Dave. Electrostatic is (as the name implies) all about static charges.

You can get static charges built up on plastic items like scratchplates when you rub your hand on them, which then discharge and you do get a definite 'static' noise picked up in this instance, But this isn't your normal 'hum', as being discussed here. It's not that common, and is down to a combination of the plastic material chosen and the particular guitar finish. Sticking copper foil on the back of the scratchplate/pickguard and grounding it this can stop this static noise.

The main causes of pickup noise are magnetic fields (which cause most of the 50/60 Hz and 100/120Hz hum) and RFI (covering a much wider range of frequencies). Both are manifestations of electromagnetic fields, but at very different frequencies. Both have the photon as the force carrier (whilst electrostatic forces are electron-based).

[ef37a]

Hi Skipper, guitars and basses pickup hum in two distinct modes. Electro-magnetic and electro-static.

I think you're using the wrong term with electrostatic here, Dave. Electrostatic is (as the name implies) all about static charges.

You can get static charges built up on plastic items like scratchplates when you rub your hand on them, which then discharge and you do get a definite 'static' noise picked up in this instance, But this isn't your normal 'hum', as being discussed here. It's not that common, and is down to a combination of the plastic material chosen and the particular guitar finish. Sticking copper foil on the back of the scratchplate/pickguard and grounding it this can stop this static noise.

The main causes of pickup noise are magnetic fields (which cause most of the 50/60 Hz and 100/120Hz hum) and RFI (covering a much wider range of frequencies). Both are manifestations of electromagnetic fields, but at very different frequencies. Both have the photon as the force carrier (whilst electrostatic forces are electron-based).

AFAIK Wonks, all EM radiation has two components (at 90dgrs?) one is magnetic the other electro-static. Like L&M you can't have one without the other.

There are 'electro-static' headphones and speakers. The copper strip in good mains and signal transformers is called an "electro-static shield". You can wrap a guitar in 1mm copper foil and earth the **** out of it. Won't do Jack to reduce the hum from a wall rat transformer. If you are rich and put it in a mu metal flight case? A good 30dB drop in hum.

"Static" electricity is a bit of a misnomer because until it MOVES we don't detect it!

Dave.

[Wonks]

I suggest you look up the definition of electrostatic.

You can detect static charge. An old-fashioned electroscope does this, but there are newer solid state devices that measure with accuracy.

Electric and magnetic fields are at 90° to one another with relation to a moving charge, but this isn't anything to do with electrostatics.

[ef37a]

I suggest you look up the definition of electrostatic.

You can detect static charge. An old-fashioned electroscope does this, but there are newer solid state devices that measure with accuracy.

Electric and magnetic fields are at 90° to one another with relation to a moving charge, but this isn't anything to do with electrostatics.

I've seen an electroscope. It moves. Ok, so I don't know enough physics to to solve the anti-matter problem but in general electronic terms we differentiate between electro-magnetic and electro-static screening.

One works around mains traffs, the other don't.

Dave.

[Hugh Robjohns]

AFAIK Wonks, all EM radiation has two components (at 90dgrs?) one is magnetic the other electro-static.

No, you're talking about the electric and magnetic fields. I think Wonks is quite right. RF interference, which is what you are describing in relation to the control cavity of a guitar, is a form of electromagnetic coupling.

However, an electric field can be created by electrostatic charges, and that's where electrostatic screening -- like Faraday Screens -- comes in.

[MOF]

Is it hum or other types of noise? Hum will be from close proximity to mains transformers or CRT monitors and a low frequency of 50/60hz, other types of interference could be from lighting dimmer switches or lcd type monitors and more objectionable and almost impossible to filter out.
It might be worth moving the bass guitar around the room to listen to the levels of interference. If it stays constant then it would appear to be that transmitter.

[ef37a]

AFAIK Wonks, all EM radiation has two components (at 90dgrs?) one is magnetic the other electro-static.

No, you're talking about the electric and magnetic fields. I think Wonks is quite right. RF interference, which is what you are describing in relation to the control cavity of a guitar, is a form of electromagnetic coupling.

However, an electric field can be created by electrostatic charges, and that's where electrostatic screening -- like Faraday Screens -- comes in.

I did not mention RF Hugh and the hums that infest guitars are normally not considered RF. Guitars hum inside buildings where there are mains currents flowing. Go only a few mtrs outside and the hum disappears but the guitar is still intercepting lots of RF energy which is not normally a problem if the amplifier is properly designed.

Dave.

[GCKelloch]

It is possible that the European Alder body absorbs more high end than a typical North Western US Red Alder body, but the Pau Ferro FB absorbs less high end than an EI Rosewood FB. The pickups are likely higher inductance than classic Fender JB pickups. That would reduce the high end response.

For noiseless JB pickups, I'd first consider the Wilde (Bill Lawrence design) "J-45". They are a highly efficient "air-gap coaxial micro-coil" design that eliminates internal coil cancellations and produces strong lower note harmonics with an open high end at least as extended as Fender JB pickups -- I think they are slightly lower inductance, but the combined coil and pole piece efficiency more than makes up for the accompanying output loss. The thinner wire coils are oriented so there are ~2x the wraps within the same magnetic aperture as a typical Fender JB pickup, and the special high permeability A2 poles increase efficiency without the excess string pull of A5 poles -- allowing for higher coil settings. Stronger lower note harmonics is very good for bass guitar, and the small/dense sensing coil means coil height adjustments make a bigger difference in the lower to upper note harmonic balance and transient response, so warmth and attack can be tuned without as much difference in overall output. At $80/ea+shipping they are fairly priced for the quality and performance you get. I don't think there is anything else available that offers the performance advantages, and certainly not in a noise-free design.

Even though they are relatively low inductance pickups, swapping the neck V pot to a 500k should suffice if you find the high end not strong enough to your liking in the neck. My guess is it will be fine with the 250k, but it's all personal preference. I always recommend a low capacitance cable for better high end extension with any pickups. It's an important part of the equation.

If it isn't done already, shielding the control cavity with Cu tape can reduce hiss, but the difference may not be noticeable. Wilde pickups already have internal shielding, so it's not necessary in the pickup cavities, but leave whatever shielding is there. Twist the pickup + & - leads as well as the output jack leads to further reduce residual noise. Remember to connect the bridge earth wire. That guitar will be dead silent with as full and punchy a sound as you have yet heard.

Here's a mint cond used set in Australia. Might be a lot cheaper than a new set shipped from the US to the UK: https://reverb.com/item/34707215-bill-l ... ss-pickups

[GCKelloch]

Ah, a Wilde J-45 user stated the inductance measurements are neck = 3.4H and bridge = 4.9H. The neck is about the same inductance as typical Fender JB neck pickup, but the bridge might actually be a bit higher. Assuming your bass has all 25ok pots, replacing either the V pots or the T pot with a 500k should offer ample high end response with a low C cable if you need it.

You might even want to install a Wilde "Q-Filter" that lowers the circuit inductance for a more extended high end with either a mid dip or bass reduction (depending if a cap is used or not). Acoustic-like tones can be had with that simple passive device. Bourns makes 250k and 500k dual concentric audio taper pots if you want a master Tone and the Q-Filter, or some variation thereof. Its a useful/simple option that offers great versatility with just the two knobs, or you could wire a "Q-Tone" on a P/P pot that switches between the tone and Q-Filter. That's the more common option.

[skipper01]

Many thanks for all this help and advise.
I ended up getting some Lindy Fralin split coil noise cancelling pickups to replace. Had to go with the +5 winding option as thats all that was available.
All control board pots and capacitor were also replaced and screening checked.
Sounds good to me and is obviously usable now.
Basically now, this has eradicated the noise/hum problem when each pickup is used singularly.
Thanks again - really interesting discussions too.

[Wonks]

Thanks for the feedback. Glad you got it sorted.

[GCKelloch]

Fralin Split coil is an interesting choice. Any phase issue between the coils won't affect a 4 string. 2x the price of the Wilde L-45S. The A5 poles would make them tonally closer to a modern JB sound, assuming they are modern A5. Fender used a weaker/softer A5 pole formula in their pickups from the early '60s on.

[skipper01]

Hi, apologies if I’m misunderstanding but I bought the jazz bass Lindy Fralin noiseless split coil pickups (set).
I kinda had a choice between 2 products/manufacturers in the shop I went too and even then was limited to what they had in there and then.
It was a punt really as I went for the more expensive ones but I think they sound pretty good to me.
Interestingly, I’ve noticed (relating to phase I guess) something unexpected.
It appears that the overall output level actually seems to drop just a bit when both pickups are on/up against say just the neck pickup being on.
I am basically DIing into a front end into a DAW.
Is that just the affects of phase and the specifics of tone/position/jazz wiring?
I wondered whether the luthier may have wired them in wrong but surely it they were wired wrong then they would be more out of phase and you’d really hear it?
I can’t imagine they have.
I’m in danger of overthinking it all! I just like to try to understand.
Again, at least now I can use it and I believe does sound better than before!
Cheers

[GCKelloch]

It was my mistake about the Split coil model. I edited my post to reflect that.

The output does drop when two pickups are in parallel because the impedance and inductance drops, and the much lower level lower note harmonics at the bridge pos don't make up for the loss when the two string sampling points are combined. The resonance freq also goes up, and may be above the critical hearing range as well as being more damped by both volume pot values in the circuit. Are the new pots 250K? I'd ask the repair person what they used, and why they made that change in the first place. Again, swapping one or all pots to 500k would give better treble if you need it.

[Wonks]

Have you still got volume/volume/tone controls or has it been re-wired as blend/volume/tone?

If the latter, then it’s possible the wrong taper ‘blend’ pot has been fitted. An A+C taper ‘balance’ pot often gets fitted when you need an N+M taper ‘blend’ pot. The former will drop the volume in the mid position, regardless of any other pickups in parallel effects.

[skipper01]

Hi, yes it’s still volume/volume/tone but just ‘better’ build quality 250 ohm CTR pots and orange drop capacitor installed and loom.

[Wonks]

Then unless the mixed position is very thin sounding (which doesn’t appear to be the case), it’s just the interaction between the two pickups in parallel.

You can try adjusting the pickup heights to get a different ‘both-on’ balance.

[skipper01]

Thanks so much for this further advise and explanation.
Sounds like it’s just a phenomenon I’ll need to work with now then. I re read your previous post that is terrific and maybe I should have gotten these to combat this issue now I understand it better.
Yes all 3 new/replacement Pots are now CTS 250k ohm Linear with an orange drop cap (.022uf I think).
It was suggested to replace as apparently the old pots and old cap were of lesser quality. Not sure if original either.
I’d be quite happy to try 500k ohm instead as highlighted for all 3.
I’d be happy for it to be a bit brighter if that’s what will occur.