Rickresource Rickenbacker Forum

antipodean wrote:A minimalist test would be to see if there is any appreciable difference in tone on a 4001/3 with the bridge pickup soloed where the neck pickup is set to different extremes of adjustment. Given there is an inverse square relationship between distance and magnetic attraction, there should be an appreciable difference in the impact of the magnetic field on string vibration as pickup height is varied.

Indeed! (All the times I've seen obvious neck pickup interference has been at maximal height.) I think that this is what I will try.

Don't know if this is related, but I noticed something about my old 4001V63, which is mono only. I would set the neck pickup volume on full, and the bridge pickup volume to 0. If I then lowered the bridge pickup (moving it away from the strings), the output from the neck pickup would increase by quite a lot. Another demonstration of the fact that I don't understand pickups.

My 1978 4001 with hi-gains doesn't seem to do the same trick.


bluewhale

Was that a real Horsey or an RIHS?

cassius987 wrote: Really? Just remove the neck pickup, continue to use the ROS jack. The bass is the same; the strings are the same; the wiring's the same. The only thing that has changed, because you are using the ROS jack and not the mono, is that one of the magnets is gone.

One thing additional to consider in ROS or on a 4000 there is only one volume pot in the circuit. This doubles the resistance to ground that the output sees as compared to two pickups in mono. There is less treble bleed due to this.

ken_j wrote:

cassius987 wrote: Really? Just remove the neck pickup, continue to use the ROS jack. The bass is the same; the strings are the same; the wiring's the same. The only thing that has changed, because you are using the ROS jack and not the mono, is that one of the magnets is gone.

One thing additional to consider in ROS or on a 4000 there is only one volume pot in the circuit. The doubles the resistance to ground that the output sees as compared to two pickups in mono. There is less treble bleed due to this.

Right, the whole point of ROS is to isolate the bridge pickup electronically for this experiment. It has its own effect, so it has be eliminated as a variable.

I tried Evan's idea tonight before transcribing some Underworld bass and I have to say I really think the B string sounds smoother and fuller. Less fret buzz/artifactual sounds muddying things up. But it's not strong enough of a difference for me to know the effect isn't just in my head, and I think it's too subtle to capture a performance that wasn't influenced by my technique. It's not as if it sounded bad before, anyway. But I think I'll leave it like it is for now as I'm happy with whatever changes may have happened.

The magnetic field from the toaster magnets will largely go up rather than side to side due to the orientation of the magnets, and it will be pretty localized to the pickup itself, so any tonal changes that were noticed between a bass like a 4000 with a single pickup vs a 4001 with two pickups would be more due to the lesser amount of wood in the 4001. It is something that could be tested with the proper equipment, but I doubt there is much difference. If I get a chance I can test my bass with my gauss meter to see where the field drops off on the pickups but I suspect it will be down to background magnetic field within about an inch from the pickup. If I get a chance to check it in the next week or two I'll post here on this thread.

Greg

cassius987 wrote:

Colonel Sanders wrote:Probably not an easy thing to investigate considering all the other variables that you cannot isolate.

Really? Just remove the neck pickup, continue to use the ROS jack. The bass is the same; the strings are the same; the wiring's the same. The only thing that has changed, because you are using the ROS jack and not the mono, is that one of the magnets is gone.

Ok, I got confused with your reference to a 4000 in your initial post.

Yes you are absolutely right if you want to investigate the magnetic pull of the neck pickup. You just remove it. A fairly simple experiment if one has some free time in front of him.

I would suspect that whatever change you will hear will be very subtle. Changing your pick will probably lead to a more drastic sound difference. Not that I want to discourage you to do the investigation!

If you now want to compare the sound of a 4000 with a 4001 without a neck pickup while being plugged in the ROS jack, then I stick by assessment that whatever change you will hear will be resulting from a combination of variables.

bluewhale wrote:Don't know if this is related, but I noticed something about my old 4001V63, which is mono only. I would set the neck pickup volume on full, and the bridge pickup volume to 0. If I then lowered the bridge pickup (moving it away from the strings), the output from the neck pickup would increase by quite a lot. Another demonstration of the fact that I don't understand pickups.

My 1978 4001 with hi-gains doesn't seem to do the same trick.


bluewhale

It has a RIHS, which has four 5/16" dia. alnico3 magnet rods. I'm going to guess and say all RIHS pickups would have that effect.

cassius987 wrote:

ken_j wrote:

cassius987 wrote: Really? Just remove the neck pickup, continue to use the ROS jack. The bass is the same; the strings are the same; the wiring's the same. The only thing that has changed, because you are using the ROS jack and not the mono, is that one of the magnets is gone.

One thing additional to consider in ROS or on a 4000 there is only one volume pot in the circuit. The doubles the resistance to ground that the output sees as compared to two pickups in mono. There is less treble bleed due to this.

Right, the whole point of ROS is to isolate the bridge pickup electronically for this experiment. It has its own effect, so it has be eliminated as a variable.

I tried Evan's idea tonight before transcribing some Underworld bass and I have to say I really think the B string sounds smoother and fuller. Less fret buzz/artifactual sounds muddying things up. But it's not strong enough of a difference for me to know the effect isn't just in my head, and I think it's too subtle to capture a performance that wasn't influenced by my technique. It's not as if it sounded bad before, anyway. But I think I'll leave it like it is for now as I'm happy with whatever changes may have happened.

Look at the schematic; the pots are separated by the unconnected/unshorted mono jack and of course separate to the stereo ROS jack.

Right, John. Were you correcting me? I must have missed something.

When I played my 4002 last summer, a latent speck of corrosion on the summing finger on the mono jack started causing me fits. So I simply plugged into the ROS jack about half way to engage just the first finger of the ROS jack, which is the neck pickup. (In this case, except for the noise from the summing finger), I noticed no difference in the tone using either the mono jack and the selector switch up compared to the first finger of the ROS jack, which since the summing finger of the mono jack is not engaged, then it is effectively the same as a one pickup instrument.

Right, but I think that may be more a question of what's going on in the wiring harness whereas I'm controlling for that by using ROS to treat the bass experimentally like a one-pickup instrument from the outset. The question at hand is, does neck pickup magnetism, particularly on a 4003 where it's close to the fingerboard, pull on the looser section of the strings enough to cause tonal or other changes? And I think the answer is that sometimes it can, but it's rare. I have seen this phenomenon cause setup problems but I was a little more curious about tone. I haven't done the real study yet but I tried Evan's idea and the B string seemed to play more evenly up and down the neck. This experience resembles the time a Toaster was causing my low E on my 4003FL to buzz out at certain notes and I thought it was a fingerboard problem, but when the neck pickup was lowered it started behaving like it should. Although the soloed pickup output is clearly lower now the tone when both pickups are combined is not that much different.

About the only time I have ever encountered anything of the effect of the magnet pulling strings out of tune or out of tone is the classic "Strat-itis" when using ultralight strings and setting the pickups too close. There is such mass to bass strings, and the neck pickup is so limited in its upward travel by the adjustment screws, and if there are any grommets between the underside of the pickguard and the pickup, that I don't think it is ever an issue with 4001/3 basses with toasters in the neck position.

cassius987 wrote:Right, John. Were you correcting me? I must have missed something.

No, I was correcting/clarifying for Ken. I just quoted the wrong post.

johnallg wrote:

cassius987 wrote:Right, John. Were you correcting me? I must have missed something.

No, I was correcting/clarifying for Ken. I just quoted the wrong post.

It is clear to me. I was just adding that info because one pot (of the same value as two) will brighten the tone.