LoZ Pickups

[Cashmaro]

I bought a Lace Alumitone Deathbucker and am amazed at the harmonics I get out of it. Otherwise, it appears to be a treble-heavy pickup. I replaced the neck humbucker on my BC Rich Warlock and I get a similar sound to the stock bridge pickup, except it is much easier to excecute artifical harmonics.

I was so intrigued, I decided that I wanted to make one myself as a project and as the Alumitones are quite pricey despite the obviously low cost to produce them.

I did a lot of reasearch, including looking through many of the posts on this site. It looks like Lace boosts the low impedance of the single loop from the aluminum bracket/ceramic magnet by adding a secondary loop (the square shaped bracket off of the primary loop) with tertiary loops, which are two bobbins wrapped with fine copper wire (AWG 43?). The two bobbins also act as a humbucker as they they can be wound out of phase. Am I correct in this?

I was looking at getting a 2.5 inch X 1 inch X .125 thk piece of aluminum C-Channel to make the primary loop, which I can cut to width. I can do the machining with a pattern similar to the Alumitone and weld on feet to the bottom for mounting to the guitar with screws. I have some rectangular Neodymium-Iron-Boron magnets I can use to replace the cermaic magnets. I assume this should give me higher inductance in the primary although the permeability of NIB magnets is the same as cermaic magnets, and from the inductance equations it appears permeability is the limiting factor for inductance. Would the NIB magnets give higher output?

What are my options for assembly from there? I don't want to just rip off the Lace design. I figure I could use a transformer (500:1 maybe) in series with a noise canceling transformer to complete the assembly. My main concern is having approximately the same output amperage/voltage as the Alumitone or other regular humbucker so I can replace the bridge pickup on my guitar.

[big_teee]

Do they sound that much better than a conventional Hi Z type pickup, or are they just unique, and you want to do something different?
I really don't see anything that lacking in regular Humbucker pickups.
I can build all the Harmonics I can stand into a regular Pickup!
T

[Cashmaro]

Do they sound that much better than a conventional Hi Z type pickup, or are they just unique, and you want to do something different?
I really don't see anything that lacking in regular Humbucker pickups.
I can build all the Harmonics I can stand into a regular Pickup!
T

They do sound better, in my opinion. Some people don't like them, or active pick ups for that matter, but they are great for my personal style. I get the same growl on my low end but the highs and harmonics do stand out better. My brother put two on his guitar, and bridge pickup has the standard growl under distortion but screams like a banshee when hitting harmonics. It depends on the listenener. You could theoretically get a similar output by switiching from 8000 turns on conventional windings with 42 or 43 AWG wire to less windings with thicker wire, getting rid of some capacitance. One issue is that more room is needed, since inductance is directly proportional to wire cross section, but number of turns squared is proportional to inductance. Correct me if I am wrong, but capacitance does shift the output curve of the pickup to the left. I couldn't hit an artificial harmonic on my original neck pickup (BC Rich BDSM) when soloing, but i often like to do my solos getting the bluesy sound I get from the neck pickup.

Plus, I think it would be fun to have another project.

[big_teee]

They do sound better, in my opinion. Some people don't like them, or active pick ups for that matter, but they are great for my personal style. I get the same growl on my low end but the highs and harmonics do stand out better. My brother put two on his guitar, and bridge pickup has the standard growl under distortion but screams like a banshee when hitting harmonics. It depends on the listenener. You could theoretically get a similar output by switiching from 8000 turns on conventional windings with 42 or 43 AWG wire to less windings with thicker wire, getting rid of some capacitance. One issue is that more room is needed, since inductance is directly proportional to wire cross section, but number of turns squared is proportional to inductance. Correct me if I am wrong, but capacitance does shift the output curve of the pickup to the left. I couldn't hit an artificial harmonic on my original neck pickup (BC Rich BDSM) when soloing, but i often like to do my solos getting the bluesy sound I get from the neck pickup.

Plus, I think it would be fun to have another project.

Sounds like fun.
BTW welcome to the Forum.
Back to the Low Z pickups.
I made a Strat Neck Pickup with 41 Ga Wire, and it was too bright for me.
The only way I could get the tone I wanted was to shorten the bobbin to fatten up the sound.
That limited the amount of wire I could put on the pickup.
so I went back to my 42 AWG Heavy coated wire.
Good Luck,
T

[Cashmaro]

Tank you T for the warm welcome.

[FunkyKikuchiyo]

I was expecting cute memes, perhaps with kittens, until I realized that it said LoZ instead of LoLZ....

[David Schwab]

There are a couple of threads here on Alumitone type pickups.

Here's a good one:

http://music-electronics-forum.com/t5447/

[Cashmaro]

There are a couple of threads here on Alumitone type pickups.

Here's a good one:

http://music-electronics-forum.com/t5447/

David,
I have scoured the threads on this site regarding LoZ pickups. I particularly find BBSailor's comments some of the most helpful, as he seemed very interested as well. I decided to start posting here because the other threads on this site made me believe this was something I could do.

My main question is what all the voodoo is in the shrinktube on the underneath of the alumitone. It looks like no one was willing to sacrifice one and take one apart, but who would a $100 a pop. It looks like 2 bobbins coiled with fine wire. I dont want to rip off his idea but I think understanding the concept helps.

I have the neodymium magnets I would like to use, and I have a chunk of scrap aluminum that I could hog out to make the bracket. I was thinking of making a 1/2 inch thick bracket to double my loop area. Since the Neodymium has a 5X gauss rating, at the distance from the strings I plan to have in my design, as the ceramic magnets, I figure I can get 10X the amount of inductance out of my primary loop. I could then use a small step-up transformer to get the voltage and amperage I need and a second transformer for noise cancellation. Excess voltage could be controlled with a resistor in series. I am not very good with electronics and the Inductance equation becomes kind of confusing with this loop geometry, but I think my assumption is correct.

I plan on using off the shelf transformers that I could hopefully tuck in the cradle of the bracket. I figure if the one I make sounds good, I could come up with a detachable pickup for my bass so I can have a bridge or neck pickup.

[Cashmaro]

David,
I was checking out your store and I see you use Neodymium in some of your pickups. What pull force is acceptable on my strings before funky things start happening? I tried using some online magnet calculatorsand it looks like the magnets I have pull with .11 lbs of force from a 3/8 inch space between the strings and the magnet. Is that too much?

[madzub]

I have taken a couple of Alumitones apart, and rewound the secondary coils with about 300 turns each of 34 awg wire, then use a mic transformer at the amp. I'd have taken photos of the innards but i haven't got a camera. I've ruined a few $100 pickups over the years due to my insatiable need to open things up. But hey, i just rebuild them better!

But yeah, it's just what you think it is, a couple of plastic bobbins through which the c-shaped core laminations fit together, with many wraps of very thin wire on the bobbins, wrapped in tape, then the wire leads and ends of the bobbins and core are potted in epoxy. Actually i think the black shrink wrap is wrapped around first, the the epoxy poured in.

[Mike Sulzer]

I was thinking of making a 1/2 inch thick bracket to double my loop area. Since the Neodymium has a 5X gauss rating, at the distance from the strings I plan to have in my design, as the ceramic magnets, I figure I can get 10X the amount of inductance out of my primary loop.

Are you saying that using a stronger magnet gives you more inductance? That is not true. A stronger magnet can give you higher output, but if you use magnets much stronger than typical, you will affect the vibration of the string.

[bbsailor]

I have taken a couple of Alumitones apart, and rewound the secondary coils with about 300 turns each of 34 awg wire, then use a mic transformer at the amp. I'd have taken photos of the innards but i haven't got a camera. I've ruined a few $100 pickups over the years due to my insatiable need to open things up. But hey, i just rebuild them better!

But yeah, it's just what you think it is, a couple of plastic bobbins through which the c-shaped core laminations fit together, with many wraps of very thin wire on the bobbins, wrapped in tape, then the wire leads and ends of the bobbins and core are potted in epoxy. Actually i think the black shrink wrap is wrapped around first, the the epoxy poured in.

madzub,

Try this. Put a series/parallel switch between your two 300 turn coils made with AWG 34 wire. This should give you about a 200 to 800 ohm output variation and provide some tonal variation almost like switching humbucker coils between series and parallel.

What is the actual size of the two small bobbins? Also, tell us the bobbin wire window size and the approximate wire size used on the coils you took apart?

By putting the microphone matching transformer at the amp end of the cable, you are preserving the beneficial features (low noise and broad, flatter bandwidth) of low impedance transducers.

Joseph Rogowski

[Cashmaro]

BBSailor,
Thank you for joining the thread. I have read many of your posts and I am pleased to see someone who has more curiosity thanI do regarding this.

Mike,
I would like to retract that statement. After reviewing some electrical engineering literature, I see that Voltage output is related to magnetic flux per Faraday's Law. The permeability of NIB and ceramic magnets is the same, and thus no inductance difference. I want to research low pass filters to see how inductance shapes the curve.

I don't know if anyone is interested in the physics aspect of this, but I'd like to be able to make a spreadsheet or a MatLab program that can calculate output based on magnet flux, coil geometry, capacitance and resistance from a unit stringpluck. I'm sure there is more variables I am missing.

Some EE references that those interested may find useful:
Generated Voltage from Changing Magnetic Field
1.2.3 Faraday

I'll pick through my EE book from college. I'd like to be able to design a pickup and have an idea of the frequency response and voltage/amperage output to reduce guessing games.

Sorry for the digression.

The magnetic field can kill sustain apparently, as I didn't think of this before. It looks like the only real advantage of using NIB magnets is that you can use smaller ones to reduce spacial constraints.

Hopefully I get a chance to have the aluminum bracket design finished and machined soon so I can post a pic.

[Cashmaro]

I tried going through the math but its above me, the circuitry is complex. However, Lace's design is easy to calculate the math if simplified to an inductor in series with two inductors in parallel.

Is there somewhere I can buy a prewound coil on a small bobbin?

If not, is there somewhere that I can buy small bobbins for my wiring?

I was thinking instead of using two coil like Lace uses in his tertiary loops, to use one bobbin with 30 AWG wire and replacing the other coil with a small capacitor to kill noise? Anyone ever try use a capacitor with a wire going to ground?

[bbsailor]

I tried going through the math but its above me, the circuitry is complex. However, Lace's design is easy to calculate the math if simplified to an inductor in series with two inductors in parallel.

Is there somewhere I can buy a prewound coil on a small bobbin?

If not, is there somewhere that I can buy small bobbins for my wiring?

I was thinking instead of using two coil like Lace uses in his tertiary loops, to use one bobbin with 30 AWG wire and replacing the other coil with a small capacitor to kill noise? Anyone ever try use a capacitor with a wire going to ground?

Cashmaro,

The math for current transformers is rather simple. Use this web link to calculate the resistance of the primary string loop (either with copper or alumium)Resistivity Calc. Then simply multiply the square of the turns ratio by the primary thick string loop resistance, typically in micro-ohms. A 500 turn CSE-187L will have an output in the 250 ohm range using an AWG 10 wire loop (about 1000 micro-ohms with a simple magnet in the center): 250,000 times the string loop resistance. A Prem Magnetics SPCT-251 with 2000 turns will calculate by multiplying the primary loop resistance value by 2,000 squared or 4,000,000 times the string loop resistance. The SPCT-251 primary is open to accomodate a square copper AWG 4 wire that is .162" square available from Surplus Sales of Nebraska that measures out at about 26 micro-ohms per inch.

You can make your own CT based pickup very easy to learn how Lace voiced the various pickups in the Alumitone Series. The CSE-187L will match directly into an XLR 3-pin input to a mic mixer or a low to high Z mic matching transformer. Attach the CSE-187L transformer secondary to pins 2 and 3 on the XLR and attach pin 1 to the low impedance string loop and the CT metal frame to keep the noise as low as possible.

As you change the wire size of the string loop and choose various CT transformers with various turns ratios (500, 1000, 2000 etc) you can control the CT output impedance and the voicing of the output sound.

Keep experimenting. This is fun stuff!

Joseph Rogowski