Jacken's Blog

My first try to write on an iPad and I’m smitten. Hopefully I’ll get one next week.

My twelve year old son want’s to learn how to program. My first idea was to teach him Ruby or Python, but I decided to go with Arduino. It’s C-based so that’s a good start I think. Were currently planning a couple of projects but so far he’s managed to get some LED’s blinking. A good start.

How very irritating. Fring used to work well with iPhones push notification. Now that they dumped Skype functionallity, I have to use Skype. And you need to start the program and hope that it’s not pushed out of memory, because then your offline. Very crappy…

I’ve just finished setting up a XEN server. I moved this blog to ipage.com, but it was horribly slow so I might as well host it myself. Thank god for 100mb internet line from bredbandsbolaget. Next step, trying to setup a MythTV backend. I tried to set up a DOMU with Smoothwall firewall but failed miserably.

This is the filter changes I did to the Gigaworks DAC to remove the second opamp and to straighten out the filter section of the DAC.

You can see the original values and the values that I changed to in parenthesis. Just tap the signal from the lifted resistors (and maybe add output caps of 4.7uF) The before/after RMAA tests of the modifications can be found here.

I’ve been modifying my Gigaworks Ebay DAC and think that the results is really showing. The second opamp is completely removed, the filter is changed to Cirrus Logics filter example from their prototype board and the first opamp is replaced with GD-Audio’s Earth HDMA. It sounds absolutely marvelous. Here’s the before and after graphs

This is the second part on how to improve the quality of an old CD player. You can find the first part here. In this section I?m going to show you how to install a better, more stable clock circuit into your 505. This particular clocks comes from Kingwa, that has a series of clocks for improving DVD players, CD players and DACs. The price is reasonable. I?ve installed them in three different units and had zero problems, so the quality seems good.

Ok, so why install a new clock? Isn?t there one in there already? Yes, your right. But by using better parts like crystals with lower ppm and also design a very clean power supply to feed the clock, you can make your player sound much better. And the reason is lower jitter.

But what is jitter? There is plenty of really good places to go read up on it. Here?s some.

http://www.audiocraftersguild.com/AandE/cd-jitter.pdf (PDF warning)

http://www.stereophile.com/reference/590jitter/

Ok, lets look at the schematic. Here you can see the clock and two capacitors, C404 and C403 and the clock is X401. The clock is feeding into the DAC (PD2029A) (you can find the complete schematic in part one)

We need to remove the crystal X401, and the two capacitors, C403 and C404. The old load capacitors are no longer needed. The next step is to connect the Kingwa clock to the DAC. As seen on the schematic, the clock is 16.9344Mhz, so we need to use the correct outlet from the Kingwa clock. There is three different divisions of the clock. You need to solder two connections. One for the ground, labeled GND, and the one just next to it, labeled 1/4F0.

Now we need to feed the signal generated from the new clock to the DAC. Connect one of them to the hole in C403 furthest away from the DAC. I put the GND line here. The other one should go where the old clock used to go. Use the one closest to the large capacitor for the DAC (see picture).

The Kingwa clock is going to need power. Any voltage between 10-30 V DC will do. I will have an upcoming article about the power supply I built for it. You will find the connectors for the power on the over side of the Kingwa clock.

Next step, testing. Put in a cd. If you have the cover removed when doing this REMEMBER DANGER HIGH VOLTAGE! No touchy touchy while doing this. Not on the part we soldered but on the power supply. Anyway, If you didn?t know this you really should not be doing this in the first place.

When you press power it should read the TOC from the CD. Press play. If the display shows the seconds ticking, you can turn the player off, unplugg and put the cover back on.

elgrandee

Why whould I need this?

All albums and songs are mixed differently. So in iTunes some albums sounds very loud whilst other is rather low. This has increased in something called the Loudness War. Producers of albums soon realized that if you mix an album really hot, it will sound louder then the other songs on crappy stereo equipment. So essentially you have a lot of music in your iPod/iPhone with albums recorded at totally different volume. That?s why you have to constantly change the volume knob to correct for this. Here Apple comes to the rescue with it?s Automatic Volume Settings. Unfortunately the algorithm Apple chose to use to determine the volume of the song is made to be quick, but not particularly accurate. This mean that the songs does come out all over the place volume vise.But there is an good solution to this problem, and it?s name is ReplayGain.

This is program that analyzes the music psycho acoustically and then makes an assessment on witch level the song/album should be. Unfortunately Apple haven?t embraced this techique even though it?s totally open. Shame on you Apple.

ReplayGain application

But there?s a sollution. An application called iVolume that goes though all your songs in iTunes and makes sure they have the same ?level?. This mean that you can be certain?in that you won?t have ear blead when a song of Sting ends and M?t?rhead comes on.

The software is super easy to use, just start it and iTunes, make sure you have ?Sound Check? enabled in preferences in iTunes. After that it?s just pushing a button.

One downside only, the price is $29.95 witch I think is a bit high. But for me It was a must, it transforms the pleasure of listening to music.