Alembic Activators - how to activate them?

[fauhsil]

Hey Guys.

I just bought a set of three Alembic pickups for strat. But I don't have any electronics to activate them - pickups only.

On Alembic forum someone wrote me that they are low impedance same as EMG's but without an onboard preamp.

Can someone give me an advice aobut preamp that I can use?


Cordially Thanks for any help.

[David King]

Welcome Fauhsil,


The Alembic pickups were probably wound with as much 38 or 39 awg as Ron could fit on them so I would expect you could get something out of them by just treating them like a passive pickup and cranking the gain up a bit. They will sound thin and shrill probably but perhaps running them through a stratoblaster circuit will make them tolerable?

BTW EMG pickups aren't particularly low impedance according to those who've taken a peek inside.

[David Schwab]

I have a set of the Jazz Bass activators here. I was surprised that they read 9.52K for the neck and 9.69K for the bridge. So they aren't low impedance at all. They are stacked humbuckers.

Also I had an older humbucker sized activator and that read 7.78K

I'd try them as is, but if you need a boost, you can use something like an EMG Afterburner or PA2.

I read Rick Turner say the regular Alembic pickups are wound with 40 AWG. They might have changed it since then.

EMGs are wound pretty much like passive pickups.

[fauhsil]

Thanks for help.

Dear David:

Alembic pickups don't need a preamp (like EMG) to perform ?

[David Schwab]

Alembic pickups don't need a preamp (like EMG) to perform ?

No. They are low output though, but they will work passively. You will probably want to boost them louder with something. Try them out first.

The preamp that comes with the Activators features a variable low pass filter for a tone control.

EMGs also don't need a preamp, but you have no choice since it's built in. But the active EMGs are probably the same as the passive HZ models, only with the preamp integrated.

[fauhsil]

Dear David, thank You for answer.

Correct me if I am wrong - Alembic pickups are not low impedance (same as EMG's) but the preamp make's it low impedance (same as EMG's).

Alembic pickups 'idea' may be compared to EMG's with external preamp ?
Alembic's without preamp may be something like EMG HZ's (not sound, only idea) ?

THX.

[David Schwab]

The original Alembic pickups are low impedance.

The Alembic pickups I've had a chance to examine, which is a set of the Activator Jazz pickups, an old humbucker sized Activator, and some AXY soapbars, all gave DC resistance readings between 7 and 9K, which is high impedance.

But they have very low output and need to be boosted up a bit.

I know a guy that was buying cosmetic seconds from Alembic cheap, and using a small JFET preamp with the.

EMGs on the other hand are not low impedance coils at all. Yes, the output of the preamp is low impedance.

[TGD]

fauhsil, EMG internal preamp is different of Activator. According with "tone modeling" technology, EMG uses a dual preamp with mid-impedance coil matched via balanced linkage and single end/low impedance output. Activator is basically a bandpass filter with mono input, single input, low impedance output and variable gain control. You should drive Alembic pickups with a common buffer with variable gain control to adjust output.

[David Schwab]

fauhsil, EMG internal preamp is different of Activator. According with "tone modeling" technology, EMG uses a dual preamp with mid-impedance coil matched via balanced linkage and single end/low impedance output. Activator is basically a bandpass filter with mono input, single input, low impedance output and variable gain control. You should drive Alembic pickups with a common buffer with variable gain control to adjust output.

The EMG preamp is a single op amp, but the coils are connected in a differential manner. EMGs are high impedance coils just like a regular pickup. If you could bypass the preamp they would work fine passive. The HZ pickups are basically the same pickups without the preamp.

The Activators preamp uses a low pass filter.

Attached is the EMG 81 preamp schematic and an Alembic Activator filter module without the volume control attached.

[TGD]

David, according with EMG schematic you mentioned, you can see dual input in inverting and not inverting IN of IC. Coils are linked in IN1 and IN2, both coil ends are linked to the ground. This configuartation is commonly called "dual inputs with balanced line." I build active pickups since 1983...

Activator is a band pass filter with fixed Q and frequency swapping.

Nothing of new under the sun!

PS. EMG HZ are passive pickups, different reactance and unbalanced line as every passive pickups.

[David Schwab]

David, according with EMG schematic you mentioned, you can see dual input in inverting and not inverting IN of IC. Coils are linked in IN1 and IN2, both coil ends are linked to the ground. This configuartation is commonly called "dual inputs with balanced line." I build active pickups since 1983...

Activator is a band pass filter with fixed Q and frequency swapping.

Nothing of new under the sun!

PS. EMG HZ are passive pickups, different reactance and unbalanced line as every passive pickups.

I understand that English is not your native language but you are incorrect on a few things.

You wrote:

EMG uses a dual preamp

It's not a dual preamp. It's a single preamp. I said it was a differential input.

You said:

EMG uses a dual preamp with mid-impedance coil

They aren't mid impedance, they are the same high impedance coils as the HZ pickups. The HZ H4 pickups are pretty much the same as the EMG-81 without the preamp.

The EMG-81 has about 5500-6000 turns of 43 AWG on each coil.

The current Alembic Activators feature shelving bass and treble controls, but the older Activators filter is a low pass filter just like the Series electronics.

If it was a band pass you would lose all your low end when swept high. But you don't. Believe me, I have the schematics. It's a low-pass filter.

Here's what Alembic says:

Alembic Activators

Why Filters?

The heart of the system is the active electronics preamp/low-pass filter module. You can adjust the gain with a small trimpot located on the preamp board. The tone coloration is adjusted by the frequency control which tunes the low-pass filter section giving you a wide range of usable tonal effects.
We selected this unique low-pass filter for our tone control through our own research that showed the low-pass filter to be the closest electronic equivalent to the waveforms of naturally resonating acoustic instruments. This yields a sound that is unlike any other pickup system on the market and lets you create music with these "natural" sounds.

And I made my first low impedance active pickup in 1981.

Here's an EMG SA and an 81 coil showing that they wind as much wire as they can squeeze on the bobbin. They are high impedance pickups just like passive pickups.

[TGD]

david, sorry for my poor english, but traslating an italian motto, you are cutting hair in 4 pieces !

I fully explained what I intended concerning EMG preamp. I said DUAL preamp, no DUAL IC or OP-AMP ! This means that whole preamp project previews DUAL inputs (In1 in inverting IN, IN2 in no-inverting IN, coil ends to the ground (balanced), MONO output. Bobbins linkage is much different respect a classic series passive pickup. In fact in an passive humbucker frequency responce, resistence and impedance are generated from the sum of both coils. In EMG preamp this operation is done by IC, is completely a different building philosophy ! I wont to bore you concerning differences, but I don't agree when you said EMG active pickups are same of HZ with a preamp. First one came from a HIFI microphonic amplification project, second is a passive pickups with unbalanced linkage bobbins downstreamed to a MONO input and OUTPUT preamp. This means active stage cut/boost the whole electromagnetic pickup features, and IC provide to change gain to the whole signal, does not sum each coil sending it in single end like EMG project. I hope my poor english explains better what I want to say; if something isn't clear please let me know I'll try to expain it again.

Impedance scale : it depence from usage parameters. For pickups purpose I ranged my own scale:

0 - 2k Low impedance
2 - 10k Mid impedance
> 10k High impedance

In other electronic applications high impedance is considered when resistence is over 1000 K, so as you can see doesen't exist a ultimate impedance range scale. If you consider 6/8K high impedance nothing change, 6/8K are !

Activator: Analogic audio project dosen't invent anything. Often you can find same basis project developed in different way.
According with electronic basic, active filters are divided by 3 types : Low pass, High pass, and BandPass Filter. BandPass filter (sum of Low and High pass filters) is the parametric EQ basis. I have also Activator project (same of your picture) and I confirm it. It's a BandPass Filter. or so we call it in Italy, I don't know in USA !

[Steve Conner]

I find it hard to believe the Alembic thing is a bandpass. Surely it's a resonant low-pass filter like the Wal thing.

The response of a parametric EQ isn't a bandpass either, though you use a bandpass filter to build one.

The main difference between active and passive pickups is just that active ones aren't loaded by the capacitance of the guitar cord. (Mine measure 750pF.) Without that capacitance, even a fairly high impedance pickup can give a full-range sound, and the configuration of the coils matters less.

[David Schwab]

davidImpedance scale : it depence from usage parameters. For pickups purpose I ranged my own scale:

0 - 2k Low impedance
2 - 10k Mid impedance
> 10k High impedance

While that is true in general, passive pickups as you find in Fenders and Gibsons are called high impedance.

Activator: Analogic audio project dosen't invent anything. Often you can find same basis project developed in different way.
According with electronic basic, active filters are divided by 3 types : Low pass, High pass, and BandPass Filter. BandPass filter (sum of Low and High pass filters) is the parametric EQ basis. I have also Activator project (same of your picture) and I confirm it. It's a BandPass Filter. or so we call it in Italy, I don't know in USA !

No, it's a low-pass filter. It removes the high end, it passes the lows. A band bass filter passes just a narrow (or wide) band of frequencies. A wah pedal is a band pass. Alembic does not use band pass filter... THEY SAID IT WAS A LOW-PASS! Why don't you call them up and tell them they are wrong.

The reason they use a low-pass filter is to reintroduce the resonant peak before roll off of hi-z pickups, since the resonant peak is very high on lo-z pickups. So it simulates the response of typical pickups, and also works as a standard tone control on passive guitars, which is also a low-pass filter.

Once again, direct from the Alembic web site:

Alembic Activators

We selected this unique low-pass filter for our tone control through our own research that showed the low-pass filter to be the closest electronic equivalent to the waveforms of naturally resonating acoustic instruments. This yields a sound that is unlike any other pickup system on the market and lets you create music with these "natural" sounds.

Does that picture say "band-pass"? Wal and ACG also have preamps with low-pass filters.

The sum of the low and high pass filters is a notch filter.

You are rapidly losing your credibility. You are wrong, and I'm finished with this discussion.

[David Schwab]

I find it hard to believe the Alembic thing is a bandpass. Surely it's a resonant low-pass filter like the Wal thing.

Alembic say it's a low pass filter. So do Wal. Someone can't read, or he's in denial.

Getting back to a way to boost the Activators. This should do the trick nicely. I built a few of these for someone to use with some Alembic AYX bass pickups. Obviously the bypass is not needed. General Guitar Gadgets sells a kit for a pedal version as well as the circuit board.

The Free Information Society - Alembic Stratoblaster Electronic Circuit Schematic