Any valuable info on Lane Poor MM pups?

[ModulusMK]

Oh nice posts!
Useful, just to do the the same magnetic view on the MM4! Anyone has it and has the magnetic paper too?

belwar, can you post some closeup pics of the LP's you teared apart, so we can see nicely what's going on inside...

The ceramic magnet doesn't look like any metal whereas alnico looks like metal, I think you can make difference between the two.
Ceramics usually have like little tiny scratches/holes at the edges, very brittle material.

Ceramic:
http://img.diytrade.com/cdimg/755097...mic_magnet.jpg

Alnico:
http://img.en.china.cn/0/0,0,313,174...1,9bda1c50.jpg

[Joe Gwinn]

The ceramic magnet doesn't look like any metal whereas alnico looks like metal, I think you can make difference between the two.
Ceramics usually have like little tiny scratches/holes at the edges, very brittle material.

The easiest way to tell (aside from appearance) is with an ohmmeter. Alnico is a metal alloy, and conducts electricity very well (so the resistance between any two points will be very low), while ferrite is a form of ceramic, and conducts electricity very poorly (resistance between any two points will be very high).

[ModulusMK]

The easiest way to tell (aside from appearance) is with an ohmmeter. Alnico is a metal alloy, and conducts electricity very well (so the resistance between any two points will be very low), while ferrite is a form of ceramic, and conducts electricity very poorly (resistance between any two points will be very high).

Yeah, this is even better idea if you have an ohmmeter. However, if you see both magnets side by side I think you can make a difference.

[Joe Gwinn]

Making one's own "magnetic paper"

The usual magnetic paper isn't very sensitive and tends to blur the field details. In the 1970s I was figuring out why a magnetic stripe writer was not working correctly. For this, I needed to see what exactly had ended up written on the magnetic surface. The bit density (50 transitions per inch?) was pretty low by present day standards, so it was possible to read the digital data with a magnifier if one used a "developer" fluid, which is commercially available to this day (but expensive).

The developer is very fine iron dust in a fluid, oil or alcohol being common choices. The commercial developer had far too much iron dust in it, yielding blurred pictures, so I made my own fluid. At first, I simply diluted commercial fluid with denatured alcohol. Later, I made my own fluid from iron dust (carbonyl iron powder from a chemical supply house).

For the magnetic stripes, I would stir or shake the developer fluid, dip the tape for a while, always moving so only particles held by magnetic force wouldn't wash away, then remove and allow to dry. One could see the dust patterns on the tape at this point, but not well and the dust image is very fragile, and needs to be fixed.

So, I laid the magnetic tape coating-side-up on a sheet of glass, and carefully rolled a strip of Scotch Magic Tape adhesive-side-down onto the magnetic tape, scrubbed the magic tape down with my fingertip, peeled it up, and put it down carefully (no wrinkles or bubbles) onto a white 3x5 inch index card, and scrubbed it down hard with a metal ballpoint pen barrel. The iron-dust image completely transferred from the magnetic tape to the index card, without loss of resolution.

Now, pickups do not require anything like this much resolution, so we can use steel filings instead of carbonyl iron dust, and pickup making generates lots of filings.

For a quick look fluid, disperse the filings in heavy mineral oil from a drug store. Be somewhat stingy with the dust, or the patterns won't be clear.

Stir the fluid and pour out into a shallow flat-bottomed glass or plastic dish. A petri dish would work. Put dish on top of the pickup. Wait ten minutes. Pick dish up carefully (no sloshing) and put it down on a piece of white paper. Inspect. If you have a light table with horizontal illuminated surface, this may make inspection and photography easier.

With an epoxy potted pickup, one can do the dust in alcohol trick, fixing with wide clear sticky tape.

[David King]

Belwar,
Was the P coil wound directly around the magnet?

[David Schwab]

I have magnetic viewing paper, but like Joe said, you don't see much. With the paper, the dark area is the magnetic pole, and the white area is the null point between the poles.

So try this, place the pickup in a zip lock sandwich bag. Then sprinkle iron (steel) filings on the top. Not only will you see where the magnetic fields are, you will see them in 3D!

belwar, ceramic magnets are a dark almost black color, and alnico is obviously a metallic color. I'd bet these are ceramic magnets from the tone they produce. Ceramics are more often used in "modern" design bass pickups, such as Bartolini, Alembic, etc.

Here's an old Alembic pickup seen under viewing paper. You can see the wide ceramic magnet used.

[David King]

Belwar, read through section III of this PDF doc
Chemical Composition of Ceramic Magnets

http://www.intl-magnetics.org/pdfs/0100-00.pdf

[Joe Gwinn]

So try this, place the pickup in a zip lock sandwich bag. Then sprinkle iron (steel) filings on the top. Not only will you see where the magnetic fields are, you will see them in 3D!

I bet for quick looks, steel filings in oil, all in the ziplock bag, would work. If one has a heat sealer, so much the better to cut down on leaks. Or, use alcohol, so the leaks won't matter.

[ModulusMK]

Thanks, Bels. I don't have a MM4 - here are the remaining Lane Poor pickups that I *do* have:

2 x JB4250
1 x SB4250
1 x JL-N
1 x M4.0 W
1 x M4.0 HB

I found the magnetic paper on eBay several years ago. I think I have a spare sheet - let me dig around a bit and I'll let you know.

tt, would you like to magnet view post the rest of your LP pickups?

[jbrew73]

does anyone have any info on the 2x1ac preamp? how about pics?

[ModulusMK]

does anyone have any info on the 2x1ac preamp? how about pics?

This is what I have, mainly the part with more valuable info, as stated from Lane Poor company:

"Our new pre-amp utilizes surface mount technology. This upwardly compatible
pre-amp started life as a reduced size version of our 1 x 1 ac.
The "2 x 1 ac," is a 2 input x 1 output design with user adjustable gain settings.
The pre-amp can be configured as a single input, 1 x 1, or as a dual input, 2 x 1. It features variable gain of 2:1 thru 15:1 and is sonically invisible.
This pre-amp can also be configured with a two or three band EQ with a cut/boost of 8db with our upcoming optional plug-in module.

In addition, we have incorporated our Patent Pending "Check it" technology right on the board. This device allows you to Visually check the amount of power in your battery as you plug in! The readings are displayed by an LED mounted on the board and can be remoted by a fiber optic feed to the pickup cavity of your instrument. Back to the bypass switch for a moment. Once the transparency question is answered the next problem that we all have with on board or external battery powered equipment is time based. How much is left. Enter Check It ©, (TM) and patent pending. The professor says it's an automatic primary cell charge indicator. In English it's a neat little device that automatically lets you know how much of a charge is left in your battery. When you plug your instrument or effect box in, there is an led that lights up for 4 seconds if the battery is full, 2 sec’s for 1/2, 1 for 1/4 and just a blip if it's almost empty. It behaves slightly differently for high, medium and low output impedance batteries. The stronger (lower) the impedance, the stronger the reaction of the circuit and the led. Check It (TM) handles the job well. The led on board the preamp can be electrically remoted via wires to a back plate or pick guard. It can also be remoted using an acrylic fiber optic light pipe. The pipe can be snaked through existing wire holes and brought out next to the surface of the instrument beside your pickup.

Tech specs. We don't have all these in yet. (We just got the first of the automatically built preamps in, they are being measured early this week.) What we do know is that they are quiet, fast and clean. Down 3db at 18 and 90k hertz. Ferrite is on board for in's, out's, and the battery connections. We are using an Analog Devices quad op amp. It costs us more than virtually all of our competitors pay for all of their components, but... it's the only one I have heard (haven't heard?) that I really like for everything that a bass can do. Clean slaps, full B strings, and very low on intermodulation distortion. (IM shows up instantly on a bass with tricky chords, like 9th's and 11th's.) Turn the gain up and go straight into a power amp or your home hi-fi!!! ("Oh no Lane don't tell people to do that!") Just watch the temptation of the loudness and bass controls.

Physical things. The LP 2x1 AC preamp measures 1.5" long by 0.925" wide and 0.5" tall. Smaller than a 9 volt battery, fits in a Jazz cavity. All in and out connections are solder free barrier strips. There are 47 components on board, 20 on the front, 27 on the back (The little things are precision low noise resistors, 1/10th of an inch long!) Surface mount technology allows us to get a lot of components into a very small space. If this were built with "standard" components it would require roughly 8 times the space. Gone are the days of big boards here. Many many thanks to Wayne Mitzen for his patience and skills in taking our ideas and making them into a physical reality. Our boards were assembled by ISO 9002 certified Distron Corporation in North Attleboro MA. The preamps come with an output jack and battery clip already connected."

[David Schwab]

Man, that's tiny!

Turn the gain up and go straight into a power amp or your home hi-fi!!!

I used to use a JFET preamp, and I was able to plug my bass right into the power amp input on my Trace combo, bypassing the preamp entirely.

What kind of op amp is that?

[ModulusMK]

It's a rail-to-rail opamp, OP484 from Analog Devices.

http://www.analog.com/static/importe...84_284_484.pdf

Hey David, will you scan the pickup part of the book? I'm asking you 3 times...

[jbrew73]

thanks for the info ModMK.

now if i could just find a schematic.

[ModulusMK]

You have a better preamps, not that LP is not good but it has less than half the amount of boost than the other two.
Like Bartolini or Aguilar, but they do not have the battery monitoring. Bartolini has an initial boost option with external trim pot starting at 0, Aguilar does not and is boost only system (OBP-1 only, other models are boost/cut). Both are great preamps with very low current dissipation and are very transparent and flat when not "EQ'd".
Bartolini is BiPolar and Aguilar is FET design.
I have the Bartolini NTMB schematic if you want.