new strobe lamp

the original neon bulb of the SP10MKII was confirmed dead.




I removed the original neon bulb and tried to make an alternative.
the strobe circuit of the SP10MKII is "flashing" at a frequency of about 105Hz at 33 1/3 rpm and about 142Hz at 45 rpm.
using LED(s) to replace the neon lamp is easy and simple.
I've made a small PCB that use the original neon mounting holes.





in order to keep it compact, SMD LEDs were used (size 0805), there is a total of three LEDs driven by a small transistor. everything is powered by a single 5V DC (from the SP10KII control board)





it looks cool, isn't it?





everything just fit to the original neon bulb mount and it also runs cooler.





yeah, here we go, the orange LEDs looks pretty good.

I can remove the 140V DC supply section now as it's only used to power the neon blub which is no longer used anymore.

new psu for the SP10

since the Technics SP10 didn't came with the original PSU, i have to build one to check its operation.

the table need +5V, +32.5V and +140V DC. and this is how it looks,



and the front,




and bingo, the SP10 is turning now but the strobe is not working, maybe a doggy neon bulb?

checking the table

the inside of the SP10II is clean and after visual check, no sign of burnt parts.




and this is the oscillator and frequency divider board, again it's clean and decent. i will change all the E-caps anyway before i proceed.

unpacking a new turntable

my new Technics direct drive turntable (SP10 mark II) has arrived finally.

the table is missing the original power supply and i will build one to make it turn. the first inspection is quite positive, it's clean and a smooth turning motor.

next is to build my custom designed motor controller. :-)

enquiry about exD

please visit here,

exD

congratulations

well done. :-)

http://www.abf-online.org/results/amfaus11.htm#Final

broken cart, broken heart .........

what more can i say? sigh ........

updates ........

more info about the USB interface will be updated here:

exD

Apple TV and Voyage MPD

have tried Voyage MPD on my ATV for a while, I can say this combo is lovely. :-)



i currently have a 4GB CF card installed, preparing the CF is simple, refer to ATV bootloader for details.

when you have completed the preparation using ATV bootloader, don't partition and format your disk again during Voyage MPD installation, otherwise you may not be able to boot properly.

when you have completed the installation of Voyage MPD, you may have to manually edit the menu.lst file, i have changed the kernel image to its absolute path instead of a link.

here is my menu.lst file,

root@voyage:/boot/grub# cat menu.lst
#
# This file generated automatically by /usr/local/sbin/setboot.sh
# on Wed Feb 23 18:02:21 UTC 2011
#
#timeout 30
default 0
title AppleTV-MPD
root (hd0,3) kernel /boot/vmlinuz-2.6.33.7-rt29-voyage root=/dev/hda4
initrd /boot/initrd.img-2.6.33.7-rt29-voyage
boot

since my USB interface is fully comply to UAC2, it works right away.

streaming 384kHz audio is just a piece of cake. :-)




here is the official Voyage MPD site,

http://linux.voyage.hk/voyage-mpd

will upgrade to Voyage MPD 0.7.5 soon.

upgraded to 32-bit

with a new firmware update, the USB interface is now capable to stream at a max. of 384kHz/32bit.

ready to ship

the new usb interface module is ready to ship now. :-)



the proposed price is:

1. 192kHz/24 bit version --- US$199
2. 384kHz/24 bit version --- US$249

full throttle

my new USB audio interface is now capable of delivering audio sample up to 384kHz sample rate.

here is the reported sample rate supported by Mac OS:





playing hi-rez audio files is really fun. :-)

you can download some DXD (352.8kHz) samples here:

2L.no

hacking Apple TV

after some listening test, i have decided to settle with linux and setting up a new cas system using an Apple TV (1st gen).



a minimal linux system will be "poured" inside this little machine and act a frontend music player. all of my music files will be placed in a NAS.

since the Apple TV (atv) is using a Pentium M processor and almost any standard x86 linux distribution will do the job.

a peep inside of the atv,



atv is not using standard BIOS, you will need a special bootstrap process in order to boot into a new OS other the standard ATV OS, i've tried this,

atv-bootloader

it works! :-)

what about Tux ?

let's try connecting the USB audio device to Linux, here is the screenshot,





it's ubuntu 10.10 which has the latest ALSA driver (with USB audio class 2.0 enabled).

snow leopard singing

the USB audio interface is now singing flawlessly with MAC OS X 10.6.5







it can stream 24/192k audio files with ease.

but remember, if you are using iTunes to play your music, it won't stream at its native sample rate, it depends on the rate that is set in you audio midi setup.

if you want to have your audio files playing at its sampling rate, you need a player software that could "switch" sampling frequency in Mac OS X.

some example,

Pure Music, http://www.channld.com/puremusic/index.html
it's non free but demo version is available.
it is basically an add on to iTunes so audio files will be played at its native rate.


Decibel, http://sbooth.org/Decibel/
it's free and formerly called "AyreWave"
again, it can play your files at its native rate but it still contains some bug .......

i'm using Pure Music at the moment.

got it, finally......

after more than a year of development, my USB audio class 2.0 interface finished.

it's complying the USB Audio Class 2.0 standard, will have native support in Mac OS X 10.6 (or later) and Linux (with the lastest ALSA). a custom (ASIO) driver for Microsoft Windows (XP and Windows 7) is also available. :-)




apart from standard S/PDIF (and AES/EBU) output, it also equipped with an I2S output.

femme fatale?

a very nice covered version.

Transistor matching

After the carrier block has finished, it's time to match the transistors.

I have built a simple curve tracer from Elektor Electronics (Feb. 2009).

More info about this Transistor Curve Tracer,

http://www.elektor-electronics.co.uk/magazines/2009/february/transistor-curve-tracer.810360.lynkx


And this is mine.




A sample screenshot of a typical 2SJ49 mosfet,

It looks like this.......

Have the TO3 transistor mounted on the carrier block and it fits very well.




More tests to follow.

Good job, boys!

Congratulations!

http://www.abf-online.org/results/ayg09-res.htm#BOTeam2







:-)