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texangerbil
New
Username: texangerbil

Post Number: 5
Registered: 11-2007
Posted on Monday, March 10, 2008 - 4:34 am:   Edit Post

Hi, I've been trawling the archives re activators and I can't find anything that really answers a question that's been bugging me - how different are Activators to "proper" Alembic pups like AXY/MXY? Do they have significantly different design and so do they sound different, or is it more a case of a standard Alembic transducer (if there is such a thing) housed in a variety of casings?

I gather AXY and MXY are the same pup just in different housings. I also understand that Series and Fatboy pups are different beasts designed in different ways. But I've not seen much discussion of the finer points of Activators.

I've read from Mica somewhere that P Activators are the loudest and Js the quietest pickup that Alembic makes. Ps must be made differently because they're in two halves, but is for example a J the same as a Rick the same as a Gibson?
keavin
Senior Member
Username: keavin

Post Number: 1404
Registered: 12-2002
Posted on Monday, March 10, 2008 - 6:20 am:   Edit Post

Here are some excerpts taken from posts made by Mica, Bob Novy, and David Fung regarding Alembic pickups.

Mica:
All the non-Series Alembic pickups are stacked humcancelling pickups, we don't make any humbucking pickups. Even the ones that look like single-coil guitars pickups are stacked humcancelling pickups. I associate humbucking pickups as designs with two magnetic core coils, and a flipping magnetic domain (the bucking part). Our design is much more simple with one magnetic core coil and one non-magentic core coil stacked and no bucking involved. I suppose in the world outside of Alembic the terms may be interchangable, though I feel the distinction is important because I don't believe the tone from our pickups is what most people would associate with humbucking pickups.

The pickups are single coil in a Series I/II system and require the dummy humcancelling pickup to eliminate the hum that plagues the single coil design.

Bob:
An AXY is electrically and tonally identical to an MXY. The only difference is that the AXY is in a larger plastic housing; the guts are identical (at some point in history, they shrunk the housing as much as possible to create the MXY look).

A FatBoy uses the same housing as an AXY (you can't tell by looking at them, at least from the top), and is the same humcancelling design and (probably?) the same number of windings as an AXY/MXY - except that it is wound on a magnet which is larger, along the direction of the strings. This results in a wider aperture, meaning that the pickup is listening to a longer section of the string, roughly twice as much.

David:
First, start with a single coil pickup. You make that by winding a coil around a magnet and disrupting the magnetic field with something like a vibrating ferrous string. The magnetic interference has the effect of generating a electrical signal in the coil, which you can amplify to reproduce an analog of the strings motion. You can tweak the sound of the pickup by varying the strength of the magnet, the shape of the magnetic field (this is the aperture), and the type and amount of wire on the coil.

The "problem" with single coil pickups is that in addition to picking up the motion of the string, they also will pick up radiated electromagnetic (EM) fields, which you hear as hum and buzz.

Humbucking and humcancelling pickups cleverly address this problem by using a matched set of pickup coils. If you reverse the polarity of a single-coil pickup magnet, you'll reverse the polarity of the output signal. You can also reverse the polarity of the signal by reversing the direction the coil is wound in. If you flip the magnet AND wind the coil in reverse, the pickup should sense string motion exactly like the regular pickup does.

But picking up an EM/hum field doesn't depend on the magnet, just the coil. If you hook up a regular pickup and a "reverse" pickup, what will happen is that the magnetically-sensed sound will add normally, but the EM-induced buzz (which isn't dependent on magnetic polarity) will add up out of phase and will be cancelled out like magic. This is how the two coils in a Gibson-style humbucker are wired, or the two halves of a P-bass pickup. In modern Strats, the middle pickup is reverse-wound/reverse polarity which is why the "in-between" tones don't hum.

In something like a Gibson humbucker, the two coils in each pickup have magnets and "hear" the string in slightly different places. This means that the audio outputs from the coils are slightly different and that small difference causes some additional out-of-phase cancellation of the audio signal. That's one reason why most humbuckers are less bright sounding than single coils.

One way to reduce the amount of high-end cancellation is to stack the two coils one above the other. It works the same as side-by-side, but both coils are pretty much seeing the same string motion now. The problem with this design is that one pickup is farther away from the string, so you still don't get a perfect signal match (the closer pickup will have hotter attack for instance, so the summed signal won't be a perfect match). This is how stacked Strat pickups work.

If you're willing to dedicate one coil to hum cancelling only, then you can perfectly capture the single coil sound by leaving the magnet out of one of the two coils entirely. The coil with the magnet "hears" the string, and the air coil only hears EM which it will cancel out of the other signal. This is what the Series bass is doing. The pickups are true single coils; the hum canceller (shared by both pickups) is a coil with no magnet which only serves to remove the hum when summed with the pickups. The EM/hum radiation is basically going to read identically anywhere on the instrument, so, with proper matching, you should be able to perfectly cancel the hum with minimal effect on the single coil sound.

[With the FatBoy,] there's a pickup on top and a humcancelling coil beneath [and thus] there's some compromise vs the Series setup. [Since] it's an air coil humcanceller, then the problem is that the proximity of the air coil to the magnets of the pickup will cause some weaker signal to be induced again mismatching the outputs. That's why the Series humcanceller is physically located away from the pickup magnets.

Whew!

A couple of additional observations. First, Leo Fender was pretty clever in making the split-coil P-pickup. By making it that way, you can build a one pickup bass that doesn't hum and doesn't have high-frequency cancellation (only one coil reads each pair of strings but together then cancel the hum). Second, if you can pry the magnets out of the middle pickup of your Strat and do a little rewiring, you'll have the purest, humfree neck and bridge pickup tones you've ever heard. I'm surprised that you don't see more Gibson-style humbuckers with a live coil and an air coil, but I guess that doesn't sound at all like a traditional humbucker.

Finally, this is a great example of Alembic's no-compromise design. There's lots of ways to get "pretty good" results, and only one way to do it that's ideal, and that's what you see on the Series. I know of only a few other basses that have this system - the original Paul Reed Smith basses had an extra hum-cancelling coil on the back, and there was a short run of Fender Elite Jazz basses that had this in the 80's. Alembic was first on this (certainly the first significant player) and never stopped since the 70's.

And Mica again:
[The middle two adjusting pots on the back plate of a Series instrument are] hum-balance pots. The hum is adjusted to null for each pickup, because even if they have the exact number of turns, each pickup is slightly different and needs a different amount of influence from the humcancelling coil.

(Message edited by davehouck on March 20, 2006)
texangerbil
New
Username: texangerbil

Post Number: 6
Registered: 11-2007
Posted on Monday, March 10, 2008 - 7:29 am:   Edit Post

Thanks Keavin. All that stuff I'd already found, although it's useful to pull it all into one place.

I guess to be more specific with my questions:

0) let's just talk about basses as that's my interest.

1) Are the Activator transducers the same as any other Alembic pup eg AXY/MXY, Fatboy or are they a different design in terms of apertures/windings etc? I understand from the above that they all use the same basic stacked humcancelling principles, but in the same way as the AXY/MXY and Fatboy have different innards, do Activators have different innards again?

2) are Activator pups all the same transducer inside with just a different shaped casing to fit eg Rickenbacker, Gibson, Jazz etc? ie will they sound identical? Or are the magnets/windings different for each model?

As a physical example, if I have a bass with AXY pickups in and I swap them for Jazz Activators, will I hear a difference, all other things remaining the same? And if I swap the Jazz Activators for Rickenbacker Activators, and then Gibson Activators, will I hear a difference?

Thanks. Maybe this is nitpicky, I'm just trying to get it straight in my own mind.
davehouck
Moderator
Username: davehouck

Post Number: 6327
Registered: 5-2002
Posted on Monday, March 10, 2008 - 4:18 pm:   Edit Post

I don't think the question is nitpicky; and I don't know the answer. I've done some searching and I can't find where the question has been directly addressed.

My guess is that the magnet in the "J" pickup is thinner than the magnet in an AXY/MXY; so I'm thinking that it should sound cleaner, other things (windings) being equal. And the magnet in a "P" is obviously different as well. Whether the width parallel to the string is the same as an AXY/MXY, I don't know. And if it is, what difference will the width perpendicular to the string make, i.e. windings? And I have no idea what shape is used for the magnets in the Gibson and the two Rick housings.

So, it's an interesting question.
mica
Moderator
Username: mica

Post Number: 5197
Registered: 6-2000
Posted on Monday, March 10, 2008 - 4:47 pm:   Edit Post

1) AXY and MXY use the same magnet and winding. If it's in an Activator, an Essence or a Signature Deluxe, the pickups are the same. The FatBoy uses the same magnet as the Series I/II, but is a humcancelling pickup where the Series I/II is a single coil

2) All activators are stacked humcancelling pickups*, but the size of the magnet is dictated by the shape of the pickup. For example, the JZ magnets are narrower than what we'd use in a standard AXY or MXY pickup.

The large RK pickup use the same magnets as the AXY so they would sound the same. The small RK pickup uses the same magnet as the HB pickup, so they would sound the same.

So, use the pickup that matches the shape you've already got in your bass. We've put the biggest magnet possible in the shapes that are not Alembic standards.

If you're building a bass, we'd encourage you to use a larger magnet, like in the AXY / MXY pickups unless you thought you would want to experiment with other manufacturer's pickups.

*Except the P shape - they are 2 single coil pickups in series with reverse magnetic and coil polarity.
davehouck
Moderator
Username: davehouck

Post Number: 6330
Registered: 5-2002
Posted on Monday, March 10, 2008 - 5:00 pm:   Edit Post

Thanks Mica!!
bsee
Senior Member
Username: bsee

Post Number: 1910
Registered: 3-2004
Posted on Monday, March 10, 2008 - 5:27 pm:   Edit Post

That is an interesting question, and one I suspect it will take Mica to answer to your satisfaction.

Twenty or so years ago I sold my first "real" bass to a guitar playing schoolmate that I used to gig a little with. It's a Univox Ric clone and he hasn't had it out of the case since. I could get it back and put Ric activators in it if I wanted it and thought it would give me a significantly different sound than my AXY or Fatboy equipped basses. One great thing about that bass for such a conversion is the large pickguard space that allows a lot of freedom to set up the electronics as one might wish.
bsee
Senior Member
Username: bsee

Post Number: 1911
Registered: 3-2004
Posted on Monday, March 10, 2008 - 5:28 pm:   Edit Post

Hmmm.... It doesn't pay to write a longer and thought out post when Mica could be around to drop the answer while one is typing...
davehouck
Moderator
Username: davehouck

Post Number: 6332
Registered: 5-2002
Posted on Monday, March 10, 2008 - 5:31 pm:   Edit Post

Bob; that happens to me too!
texangerbil
New
Username: texangerbil

Post Number: 9
Registered: 11-2007
Posted on Tuesday, March 11, 2008 - 2:25 am:   Edit Post

Excellent. Thanks very much Mica (and others) - that goes a long way to explaining the situation. The icing on the cake would be a table of equivalents, ordered by magnet size, which would be perfect to drop into the FAQ/Reference section. From the above, I might try and start it off as follows:

Fatboy = Series I/II(single coil)
AXY = MXY = RK bridge
HB = RK neck
JZ

How am I doing? I hope this isn't dragging out too many trade secrets!
terryc
Senior Member
Username: terryc

Post Number: 455
Registered: 11-2004
Posted on Tuesday, March 11, 2008 - 5:54 am:   Edit Post

texangerbil - I installed a P/J set with twin vol, treble and bass controls in my japanese Squier Precision bass. I did all the routing for the rear J pu and enlarged the existing control cavity.
The sound changed dramatically, it became 'hi fi' and had that 'Stanley Clarke' sound but it was also close to the 'Marcus Miller' sound.
It was my main bass until I got my MK Signature 10 years ago and my son uses the Squier now.
The Bass/treble controls do not have a centre detent, they sweep from full bass/treble to cut.
Matched with a BaddAss II bridge it is a wonderful bass both to play and hear.
The J pu has a lower output but this can be balanced with the trimpots(as said before), the P pu is indeed a monster tone, in fact I think I could have got away with just the P Activator but I thought the P/J set would give me more choice.
In a nutshell it was money well worth spent as it sounds great at both lower and higher volume.
If you cannot afford a full blown Alembic then these pu's are the best option, forget the rest of the competition, get the Alembic Activators.
adriaan
Senior Member
Username: adriaan

Post Number: 1825
Registered: 6-2002
Posted on Tuesday, March 11, 2008 - 6:11 am:   Edit Post

The newer bass/treble controls should have the center detent.
terryc
Senior Member
Username: terryc

Post Number: 456
Registered: 11-2004
Posted on Tuesday, March 11, 2008 - 7:24 am:   Edit Post

Adriann - I gather they are, mine ovre over 12 years old in the Squier
Still play it when I can get it off my son, always have tune the E as he plays it in D(heavier sound I assume - Dillinger Escape Plan, Funeral for A Friend et al he is into)
adriaan
Senior Member
Username: adriaan

Post Number: 1826
Registered: 6-2002
Posted on Tuesday, March 11, 2008 - 8:17 am:   Edit Post

At age 14, my Epic has non-detented tone controls too.

(Come to think of it, it's my Spoiler's 20th birthday on the 23rd! That one was supposed to get a non-detented blend pot, but somehow that wasn't to be.)

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