You mean a real long scale bass if the active and dummy are both between bridge and 24th fret!
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Magnets & Copper Wire: A Pickup Building Thread
- Thread starter Freekmagnet
- Start date
In an Alembic, I am sure the buffer is isolating the pickups from the tone controls, so there won't be the normal resonant peak as a passive pickup and should have a bit more top end extension.One specific clarification: In Alembic Series 1 / Series 2 instruments, i.e. the ones with true single-coil pickup + a separate dummy humcanceller pickup, all 3 of the "pickups" immediately hit a high-input impedance opamp buffer before they interact with each other.
Feel free to correct me if this not the case, but I believe that if you're building a system with buffers like this, then the dummy pickup shouldn't affect the resistance/inductance of the single-coil pickups.
This is pretty above-and-beyond compared to almost all other basses out there, though, so for any basses that use dummy humcanceller pickups without these internal buffers, yes the resistance/inductance would be affected.
As to whether the buffers perfectly preserve the "plain single coil" sound - I'm sure Alembic would say yes, but my best guess is that the answer is "There is a slight impact, but it's closer to true single-coil tone than without buffers."
If you put the tone controls on the working pickup before the buffer, it should sound like a normal single coil.
I guess Alembic filter preamp works as a buffer as well. When both pickups have their own filters both pickups are buffered before volumes and pickup selector.
Good news! It'll be incredibly quiet! You won't hear anything!
(8200000 is 2500km in feet)
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Whoops I just realized the round trip would be 5000km long (2500km to the pickup, 2500km back), so the above result isn't valid. Who knows, we might even be able to get a quieter circuit this way!
To be serious for a moment: Somebody who knows better should correct me, but I'm not sure whether a dummy coil has to be under the strings, does it? I assume that without magnets it can't generate current when a string vibrates over it, so it shouldn't matter where it's placed (modulo our discussion of wire lengths).
One modified Starfire that has Alembic electronics and pickups (modification done by Alembic) has dummy coil insida control cavity so I guess the orientation or location of a dummy does not matter.
To buck hum, the dummy coil just needs to be in the same proximity to the pickups 60 cycle source's EMF. The sources EMF will wiggle the electrons in the dummy coil the same as the pickup's, and since they are out of phase, cancel out the tone of the source.
I would suggest, the orientation of the dummy coil DOES matter. Ideally, the windings should be in the same plane as the active coil. The location, as others have said, could be anywhere on the instrument.
If I saw correct the pickups were like (looking at the top)
I I and dummy was — in the control cavity. I think they were in the same plane.
That makes sense... assuming a guitar is lying flat on a table, then both the pickup and the dummy coil should be wound around a vertical axis, with one wound clockwise and the other counterclockwise (to think things through for a moment: If the dummy coil was rotated 180°, it would no longer be reverse-wound). But would it matter if the dummy coil was rotated on the core's axis relative to the pickup?
Hoping that a picture is worth a bunch of words: Pickup/dummy coil pair A below is usually how they're arranged. Pair B apparently works, and I'm assuming pair C would work, but would it?
That modified Starfire was just like C and it was made by Alembic. I believe they know a lot about dummy coils so I’m pretty sure C works.
I disagree. However you rotate the coil, the orientation of the winding never turns into its own opposite.
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I disagree with your disagreement. If you flip a coil upside down, the winding is reversed from what it was.
No it isn't. Imagine a bolt lies on the table in front of you. Its head is on your left. Now you flip it, so the head is now on your right. Has it now become a "reverse wound" bolt, that will only fit into ?
The thread is the same, only the head points the other way. If it had been a headless bolt, and you flipped it, it would be the same bolt as before.
I agree with both of you. This is why it is best if I don’t wind pickups.
Using your bolt analogy, if I take a threaded rod and flip it over, the threads still force me to turn the nut to the right. Those turns should reverse if I flipped the rod, but they don't because they are now turning in the opposite direction.
