Sunday, December 29, 2013

My LM1875 Evolution

I've been quite some time away from the DIY world actually, and even decided to give up the idea of building my own sound system. Further, I bought a 2.1 system, an Edifier C3 to be precise, and decided to stop my DIY hobby. Then I started collecting FLAC files from the Internet, listening to some audiophile musics through this nice Edifier C3 which is not bad at all. But the same old nostalgic feeling came across and I started to question my listening experience with Edifier. Later, I started to check my account at and renew my password since I have long forgotten it. The rest is, you've probably guessed that

On December 29, 2013 the schematic was updated as follows:

A fellow DIYer reminded me to route the blocked DC offset to ground through 22 k resistor from entering IN(+) of the amplifier. Another fellow recommends higher value (470 uF) of NFB-shunt capacitor. A zobel of 10 ohm resistor in series with 100 nF capacitor is installed before the output capacitor (4700 uF) near the speaker terminals. Now this amp plays Deep Purple's Pictures of Home, Duran Duran's Rio and Avenged Sevenfold's This Means War very nice. Treble and bass are just enough. :-D

Saturday, May 11, 2013

Node Ordering (1)

Random matrix of 20 x 20
Maximum number of branches per node is 4

Random matrix of 200 x 200
Maximum number of branches per node is 200

Random matrix of 1000 x 1000
Maximum number of branches per node is 1000

Tuesday, January 15, 2013

Raspberry Pi and OpenELEC. From a not-so-smart TV to a smarter one. :-)

So here I am, getting into this Raspberry Pi world. After reading here and there, I decided to give it a go. I contacted a so-called distributor in Jakarta (not sure if it's an authorized dealer) as I can remember the nearest one is in Singapore. This guy sell Raspberry Pi with a good price as I reckon from various sellers in Indonesia. A friend of mine in Jakarta helped me buying four of them from this store. So I got it now. Well, my motivation initially was trying to implement a "cheap" parallel computing for my spare time (night time as I am a bit busy day time). I encountered a blog page called "My Life with Pi" and inspired by this blog, I thought this might be interesting to try it.

However, my first attempt in using Raspberry Pi was for a home entertainment application. It was because my other friend whom I asked to buy from the Internet before I got a contact of a seller in Jakarta, informed me that my order had arrived at his home. Now there were 5 Raspberry Pis with me and 4 would be configured for a parallel computing application. What about this newly arrived Raspi? Hmmm.... thinking of an entertainment center then I thought it would be a good idea to implement it for a home entertainment center.

After reading some arguments on which XBMC implementations is the best performer (among Raspbmc vs XBian vs OpenELEC), I was convinced that OpenELEC should have its opportunity to serve for my need. Well, I've got a 21" LCD TV by LG which was not so-smart but equipped with a USB port (for maintenance, the manual said and therefore is not capable of reading data from any USB storage) and an HDMI port. I also already got a 2 GB MicroSD+adapter from my old mobile phone including a microUSB cable for charging that good old phone. Lucky me, I could save much of my time building the XBMC by only downloading the already-prepared image from this guy SPARKY0815. I downloaded the 2GB image of Raspberry Pi already configured for OpenELEC.

Following the instruction from ASK UBUNTU, I managed to burn the image to my MicroSD. Here are the commands:
1. Find out which device to burn by checking the change before and after issuing this command
ls -la /dev/sd*

2. Locate where I put the downloaded image, in my case it's here:
/media/DATA/Works/RASPBERRY/OpenELEC\ Image/2GB/OpenELEC-RPi_2GB_SDCARD.img\

3.Issue this command to burn the image onto the SD Memory:
sudo dd if=/media/DATA/Works/RASPBERRY/OpenELEC\ Image/2GB/OpenELEC-RPi_2GB_SDCARD.img\ of=/dev/sdb

Please note the escape "\" was used because we have a space between the words.

After waiting for a while. The burn process is finished and it is ready to install. So I inserted the SD into Raspberry Pi and connect the HDMI and the USB ports on my old LG LCD TV. Switch it on and Raspberry Pi booted. And the CONFLUENCE interface appeared on my screen. What fascinated me more was when I found out that my remote control could be used to interact with the OpenELEC menu. Now I have these devices (my laptop, a Samsung Smart TV and a newly-smarter LG LCD TV) connected through a TCP/IP network at home and share the files through Windows Share (Samba) service.

I also found that my Samsung SmartTV's remote control works better when I connect the OpenELEC to it. But this TV is already smart and no need a knowledge upgrade :-D

Well, my previously not-so-smart TV is now smarter enough by only adding about 500K rupiahs. :-D