31 de mayo de 2011

What Are Alnico Pickups? Article from Fender® News

What Are Alnico Pickups?

The same physical properties of alnico found in the child's toy magnet set above also make for great-sounding pickups on the American Deluxe series Stratocaster below.

When guitar shopping at a retail outlet or online, you’re bound to run across mention of alnico pickups. What does that mean? What are alnico pickups and what do they do that non-alnico pickups don’t?

First let’s explain the word itself. Alnico is an acronym comprising the first two letters of three different metallic elements, aluminum, nickel andcobalt.

Second, let’s explain what’s special about alnico. In the early 1930s in Japan, alloys of iron, nickel and aluminum were found to display twice the strength of the best steel magnets of the time. Cobalt was soon found to be a useful addition to the mix, as cobalt alloys are highly corrosion-resistant. Iron alloys that contain alnico display a high resistance to heat and to loss of magnetism, and are hence used to make strong and durable permanent magnets. In fact, before the development of rare earth “super” magnets (i.e., neodymium and samarium-cobalt) in the 1970s and 1980s, alnico magnets were the strongest magnets you could get, capable of producing strength at their poles as high as 3,000 times the strength of the Earth’s magnetic field.

In a nutshell then, alnico alloys make for very strong, long-lasting magnets.

Given their strength and durability, alnico alloys were consequently adopted for widespread consumer applications in which magnets with such properties were especially useful, such as electric motors, sensors, loudspeakers …

And electric guitar pickups. At its simplest, an electric guitar pickup consists of a permanent magnet wrapped in coils of wire, so it stands to reason that high-quality magnets such as those containing alnico would make for high-quality guitar pickups. And that they certainly did—alnico-magnet pickups were found to produce a smooth, warm and highly musical tone.

Sure enough, Fender started making pickups with alnico magnets as early as the late 1940s. Back then, alnico was the high-tech material of the age, and Fender continued to use it through the 1950s and 1960s. Technically more efficient ceramic magnets took over in a wide variety of commercial applications starting in the 1960s, but ceramic-magnet guitar pickups were found to have a generally harsher, more brittle sound with sharper peaks than their alnico predecessors. Many players and hence many manufacturers—Fender included—stuck with the mellower rounded-peak tone of alnico pickups (analogous to “worn shock absorbers” in the words of one pickup expert), and their use continues to this day (more on that presently).

* * * * *
Another element you’ll run into when guitar shopping is that there are different kinds of alnico pickups, usually designated by Roman numerals—i.e., alnico II, alnico III and alnico V (although you do see standard Arabic numerals 2, 3 and 5 just as often, really).

The alnico number is used to differentiate the strength of the magnetic field produced; it designates a sort of “recipe” in which the percentage of the different elements in the alloy varies slightly. While all three are actually pretty close, the type of alnico used, when combined with other elements such as the art of pickup placement, does affects the sound of an electric guitar.

Where it gets a bit strange, however, is that alnico numbers do not increase in order of magnetic strength, as you might at first suppose (i.e., II being the weakest, III in the middle and V the strongest). On the contrary, the order of magnetic strength goes like this: alnico III has the weakest magnetic force; alnico II is in the middle and alnico V is the strongest.

Alnico II is what you find on the earliest Telecaster® guitars of the 1950s. It is especially good for middle-position pickups, and it contributes to a very sweet and musical “vintage-y” sound.

Alnico III is the weakest of the three because it actually contains no cobalt. Since it exhibits the least amount of magnetic pull, it’s the type that impedes free string vibration the least, hence making it a great choice for neck pickups (over which there is usually the greatest amount of string vibration). This is the type used in the first Stratocaster® guitars in the mid-1950s, and use of this particular alnico blend is one of the reasons why their neck pickups sound so amazingly good.

Alnico V is the strongest of the three; more powerful in tone and response. Its greater output makes it a good choice for bridge pickups, over which there is usually a smaller amount of string vibration. Good for an aggressive, punchy sound.

As noted, Fender continues to use alnico pickups in many of its guitars. Good examples include Highway One series guitars, which use alnico III; American Standard and American Special series guitars, which use alnico V; and the American Vintage series ’62 Stratocaster Reissue, which uses three alnico II pickups. And in a nuanced nod to the art and science of pickup construction and placement, current American Deluxe series Stratocaster models have an alnico III neck pickup, and alnico II middle pickup and an alnico V bridge pickup.

Source: http://www.fender.com/news/index.php?display_article=663&EDID=KECT0K4-SQP1-BS9O0-XHUCC-VGOM-v1

30 de mayo de 2011

Al día de la fecha

Hoy es para mi un día interesante, intenso lleno de colores, entusiasmos, ansiedades y expectativas.

Y deambulando los vericuetos de mi mente me acordé de un pedacito de la letra de un tema, que me dieron ganas de compartir:

Oh! Inmortal poseidon, el del furioso tridente,
a ti me encomiendo en esta difícil empresa,
propicia que este velero llegue a buen puerto,
permíteme llevar a cabo los designios de Afrodita nacida de las olas,
¡Oh! Calíope, augusta entre las musas,
haz florecer el jardin,
trae la rima.

24 de mayo de 2011

Link a video de Youtube que empiece a reproducir en un instante dado

Tip interesante:

¿Cómo pasarle un link a alguien de un video de Youtube, pero que cuando lo vea empiece a reproducirse desde cierto minuto y segundo?


Link base:
Momento en que quiero que se empiece a reproducir cuando abra el link:
cero minutos, once segundos
Link con un tiempo en particular para el inicio de reproducción:
Notar el "t=0m11s" al final del link. "t=0m" indica la cantidad de minutos y "11s" los segundos a desplazar, desde el inicio del video, al empezar a reproducir.

Post dedicado al copado de Ale Peralta, que me hizo conocer este truquito.

[Update: ¡Gracias Humitos ( humitos.wordpress.com ) por el comentario! ]

23 de mayo de 2011

Fix file permissions in Mac OS X

A few days ago I copied a bunch of files/folders from an external NTFS formatted hard drive to my MacBook. The files where copied ok, but the permissions where messed up.

How did I fix them? With this simple command:

$ chmod -Rv u=rwx,g=rx,o=r username path_to_base_folder

It recursively goes through all files and folders and fix their permissions.

Una araña que se puede comer un pájaro

Fran Herrero, un amigo de la facu, me pasó esta foto:

¡Sí! ¡es una araña comiéndose un pájaro!

Me puse a buscar un poco. Resulta que se llama "golden orb weaver" ese tipo de arañas. Son enormes y tienen un veneno neurotóxico similar al de las viudas negras(si bien muchísimo menos poderoso).

Muchas imágenes: Link.
Artículo de la Wikipedia, con muchas fotos: Link.

20 de mayo de 2011

Acordes de Elephant Gun, de Beirut

Si bien este tema, la banda Beirut lo toca con ukelele, encontré una excelente adaptación para guitarra acá, lugar del cual proviene el resto del contenido de este post.

Update: Para los que, como mi amigo Humitos, quieren ver y escuchar el original, agrego un videíto de Youtube:


Elephant Gun

For ukelele tuned a 1/2 step up (G# C# E# A#)

Am: 2003
D7: 2223
G: 0232
C: 0003
C/B: 0002

To play on guitar, capo VI:

Am(Em): 022003
D7(A7): x02223
G(D): x00232
C(G): 320003
C/B(G/F#): 320002 -or- 2x0003


Am D7 G C C/B  x2


Am          D7                   G
   If I was young, I'd flee this town

     C      C/B     Am
I'd bury my dreams under - ground
       D7             G             C      C/B
As did I, we drink to die, we drink ton - ight

Am          D7             G
   Far from home, elephant gun
                C    C/B    Am
Let's take them down one by one
             D7                  G                C   C/B
We'll lay it down, it's not been found, it's not ar - ound


Am         D7        G        C     C/B   Am
   Let the seasons begin - it rolls right on
        D7        G              C   C/B  (Am)
Let the seasons begin - take the big king down

Am         D7        G        C     C/B   Am
   Let the seasons begin - it rolls right on
        D7        G              C   C/B  (Am)
Let the seasons begin - take the big king down


Am D7 G C C/B  x4

Am     D7    G
    Oh oh oh oh
   C  C/B (Am)
Oh la la  la   x4

Am D7 G C C/B  x8


Am             D7          G          C   C/B     Am
   And it rips through the silence of our camp at night

            D7          G         C  C/B Am
And it rips through the night  oh la la  la

            D7          G              C    C/B Am
And it rips through the silence of our camp at  night
            D7          G                    C       C/B       (Am)
And it rips through the silence, all that is left is all that i hide


Am D7 G C C/B to end

Note for Guitarists

The “low” string on a ukulele is higher than the next two subsequent strings. So, while the strings go G C E A, the relative pitches (1 being low, 4 being high) are 3 1 2 4. To replicate the sound, you would have to replace your D string with something much thinner (i.e. whatever you use for your high E) and tune it up an octave.

19 de mayo de 2011

How to install NINJA-IDE in Mac OS X (Snow Leopard)

UPDATE: For Mac OS X Lion instructions, see here.

I wrote this for the Wiki of NINJA-IDE project to help people install it after making the port of NINJA to Mac.

How to install in Mac OS X (Snow Leopard)


There are many ways to install the requirements for Ninja-IDE to run. Here my
aim will be to write a guide as straightforward as possible to get you runing
Ninja in a glimpse.
Then, I'll give a rough guide for more advanced or curious users than want to
perform their own installation their way(for instance, using a virtualenv).


We'll need to install the following:
  • Mercurial (to checkout and keep track of Ninja repo in Google Code).
  • Brew (a.k.a. "HomeBrew", an awesome Mac OS X package installer that resembles apt-get a lot)
  • Qt
  • PyQt

Install Mercurial
  • Go to [http://mercurial.berkwood.com/ http://mercurial.berkwood.com/]
  • Download and install the latest version of the Mercurial binaries.

Install Brew

* With this command, you get Brew installed to /usr/local.
$ ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"
HomeBrew project site: http://github.com/mxcl/homebrew

Install XCode
  • You can get the latest version of XCode from Apple [http://developer.apple.com/technologies/xcode.html here]

Install sip, Qt and PyQt

  • From a console, run the following commands:
$ brew install sip
$ brew install qt
$ brew install pyqt
$ easy_install rope
$ easy_install pygments

Note: Brew downloads the source of the packages and compiles it and as some of the above listed programs are quite big, it is natural for the compilation to take A BUNCH of time.

Check installations:
To check the installation details for the packages you install using brew, run a command like this(in this example, for "pyqt" package):
MacBookPro:Cellar matias$ brew info pyqt
pyqt 4.8.3
Depends on: sip, qt
/usr/local/Cellar/pyqt/4.7.7 (537 files, 19M)
/usr/local/Cellar/pyqt/4.8 (525 files, 19M)
This formula won't function until you amend your PYTHONPATH like so:
export PYTHONPATH=/usr/local/lib/python:$PYTHONPATH

Clone Ninja-IDE repository:
$ git clone https://github.com/ninja-ide/ninja-ide.git ninja-ide

Run Ninja
$ cd ninja-ide
$ python ninja.py

Note: If you get this error:

MacBookPro:ninja-ide matias$ python ninja.py
Traceback (most recent call last):
File "ninja.py", line 59, in
ninja_ide.setup_and_run() File "/Users/matias/Dev/ninja-ide/ninja_ide/__init__.py", line 40, in setup_and_run from ninja_ide import core, resources File "/Users/matias/Dev/ninja-ide/ninja_ide/core/__init__.py", line 4, in
from ninja_ide.core.core import run_ninja File "/Users/matias/Dev/ninja-ide/ninja_ide/core/core.py", line 6, in
from ninja_ide import gui File "/Users/matias/Dev/ninja-ide/ninja_ide/gui/__init__.py", line 1, in
import qt File "/Users/matias/Dev/ninja-ide/ninja_ide/gui/qt/__init__.py", line 1, in
from ide import IDE File "/Users/matias/Dev/ninja-ide/ninja_ide/gui/qt/ide.py", line 6, in
from PyQt4.QtGui import QMainWindow ImportError: No module named PyQt4.QtGui

add this line to your ~/.profile file to amend your PYTHONPATH:

export PYTHONPATH=/usr/local/lib/python:$PYTHONPATH


17 de mayo de 2011

Python: Removing duplicates from a list in one line

Yes, indeed, Python rules:



This way the order is preserved and looks nice:

+Franco Pellegrini

Playing with Python: deciding if two words are anagrams

Very little script I made that checks if two strings(or words) are anagrams:

def are_anagrams(string1, string2):
    string1 = list(string1.lower())
    string2 = list(string2.lower())
    return string1 == string2

If you thought: "Hey, dude, what's an anagram??", take a look here first. Also, this is a very nice online app that finds anagrams for words you provide: http://wordsmith.org/anagram/

16 de mayo de 2011

¡Nuevo diseño!

Al fin me decidí y me puse a renovar el diseño de mi blog.

Me gusta cómo quedó :)

Cuento de Joaco

Mientras Joaco ( http://focojoaco.blogspot.com ), un gran amigo, me daba una mano con un proyecto en Haskell, tuvimos que esperar un ratito que se descargara un archivo. En ese momento, Joaco improvisó un mini cuento.

Les comparto:

cuando la nutria sale de su madriguera, se puede oler el olor a coco rayado de los caramelos m&m que su mama le compraba de pequeña, su mama mandril y su papa oso

Brillante :)

Haskell in TextMate

How to install the bundle:

mkdir -p /Library/Application\ Support/TextMate/Bundles
cd /Library/Application\ Support/TextMate/Bundles
git clone https://github.com/textmate/haskell.tmbundle
That's it!

Some references here: http://pysvn.tigris.org/project_downloads.html

How to install pysvn inside a virtualenv in Mac OS (Snow Leopard)

Using the url to the sources is more portable and works in Mac OS X too.
(pip doesn't find it in PyPi), so I set up the pip requirement with the
path to the .tar.gz with the source:

$ http://pysvn.barrys-emacs.org/source_kits/pysvn-1.7.5.tar.gz

If you are using a virtualenv, you'll need to create a symlink. Something like this:

$ ln -s /Library/Python/2.6/site-packages/pysvn/  /lib/python2.6/site-packages/pysvn
Check it worked:

(Env)MacBookPro:viaadmin matias$ python
Python 2.6.1 (r261:67515, Jun 24 2010, 21:47:49)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pysvn
>>> pysvn.version
(1, 7, 5, 1360)

9 de mayo de 2011

How to install pycripto in Mac OS X Snow Leopard

The command:

$ pip install pycrypto

throws this error:

(....lots of lines....)
error: command 'gcc-4.2' failed with exit status 1

try this(it worked perfect for me):

$ ARCHFLAGS="-arch i386 -arch x86_64" pip install pycrypto

ipdb sometimes goes crazy too

Debugging a post request from a Django dev server with ipdb, I got that:

ipdb> print request.FILES.get('data_dict.pickle')
ipdb> request.python(3743,0x1019c1000) malloc: *** error for object 0x101cf5950: incorrect checksum for freed object - object was probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug
Just wanted to share that :)

6 de mayo de 2011

Django mode for TextMate

Developing with Django using TextMate?

Take a look at this!


mkdir -p /Library/Application\ Support/TextMate/Bundles
cd /Library/Application\ Support/TextMate/Bundles
svn co http://svn.textmate.org/trunk/Bundles/Python%20Django.tmbundle/
git clone https://github.com/textmate/python-django-templates.tmbundle.git

Just set the language of your files to "Python Django" and that's it!

PEP8 check in TextMate

I think any serious programmer that codes with Python should try to get his/her code as close as possible to PEP8.

Many IDEs have their own way to perform static PEP8 code checks. If you use TextMate, here is a way to go:



cd ~/Library/Application\ Support/TextMate/Bundles/
git clone git://github.com/astrofrog/python-pep8-tmbundle.git "Python PEP8.tmbundle"
cd Python\ PEP8.tmbundle/
git submodule init
git submodule update
osascript -e 'tell app "TextMate" to reload bundles'

shift + crtl + command + v

And that's it!

5 de mayo de 2011

Más sobre Papúa Nueva Guinea

Estuve mirando un poquito en la Wikipedia el artículo de tal país(acá).

Resulta que la capital se llama Port Moresby y es un país megadiverso.

Acá va una foto del puerto de la capital:

¡Bonito lugar! :)

Objetivo para este año: quiero tener una visita en mi blog de alguien de Papua y Nueva Guinea

Bueno, eso, antes que termine el año quiero tener una visita en mi blog de alguien de Papua y Nueva Guinea.

Porque, después de todo, ¿Quién dijo que todos los objetivos de uno tienen que ser cosas elegantes y suntuosas como "implementar un algoritmo de ordenación de O(1)", "plantar 12 mil árboles", "escribir un libro" o así?

Make svn ignore some files

Here goes another post for something I forget all the time how to do: telling svn to ignore some files:

$ svn propedit svn:ignore .
This will open a text editor. Write the filenames, extensions, whatsoever you want svn to ignore(like "*.pyc", "*.db", etc), save the file and commit.

That's it!

1 de mayo de 2011

De cero a Django en 30 minutos: videos de la charla

PyDay Córdoba - Mi charla sobre Django

Después de la choripaneada, el ping pong con la gente de PyAr, los comentarios super apasionados respecto de las bases de datos no relacionales de Emiliano Marcozzi y las infaltables y fabulantásticas charlas geek, termina el PyDay Córdoba 2011.

Estuvo muy bueno, la verdad. Excelente la organización de Juan BC.

De paso, aprovecho este post y dejo el material de mi charla sobre Django:

Están las filminas(pasadas a PDF) y el código completo del ejemplo que mostré. Cualquier cosa, ya saben, me tiran un mail a scoobygalletas@gmail.com.