
Part two of this series is now up. Read on how to install a better clock.
So I bought this Pioneer PD S-505 for $40 to test how good audio quality I’m able to squeeze out by modifying it. But I’t wil not be just the standard subjective judgement of improvement but also measurements. Back in 2000 you had to pay about $400 for it. It uses the stable platter which means you have to put the CD in upside down. So let’s get going.
The steps I planned is the following:
- Remove the mute transistors.
- Replace the output opamp
- Remove headphone output
- Replace the clock with a GD-Audio clock
- Improve the regulated voltage feeds to the DAC and opamp
- Improve the power supply
- Add a separate regulated power supply for the clock and opamp
But first we need the schematic of the player, so
download the Pioneer PD-S505 schematic here.
Ok, lets look at some stuff we need to do. First we have to remove the mute transistors. Less stuff in the audio path equals better sound. The transistors is just there to make the measurements look better for reviews. So they have to go.

Click for larger image
So transistors Q403, Q404, Q453 and Q454 is removed. Desolder och just clip the pins (carefully) with a wire cutter.

Next step, time to desolder the opamp which is a rather old opamp (NE5532). Desolder the opamp IC405 and solder in a socket for easy testing with different opamps. I settled on LM4562 at first.
Remove the heaphone opamp if you don’t going to use it. It’s better to buy an external headphone amplifier like V-CAN Tube Headphone Amplifier or better.

That’s about it for today. Next installment, upgrade the clock to improve jitter numbers…
On to part two on how to add a better clock to your PIONEER PD S-505
My friend Pär and I have this reacurring event where we meet up at my place, eat dinner and then sit around hacking on our computers. Showing off all the new stuff we found on the net, programming tips and new software recommendation. It’s a nice little event. Looking forward to tonight.
I’ve installed MAMP on my Mac to do some changes to my blog. I tried to set the WordPress wp-config.php file to connect to localhost:8889, but got an error that It could not connect to the database. After replacing localhost:8889 to 127.0.0.1:8889 it works. My quick guess is that permissions for the root user is set to allow connections 127.0.0.1, but not localhost. Anyway, it works now.
My wp-config.php file looks like this:
define('DB_NAME', 'wordpress');
/** MySQL database username */
define('DB_USER', 'root');
/** MySQL database password */
define('DB_PASSWORD', 'root');
/** MySQL hostname */
define('DB_HOST', '127.0.0.1:8889');
There’s a lot of articles on the net about modding and enhancing the sound quality of your audio equipment by replacing components etc. But you never see measurements to backup their claims. Well, I’ve been busy the last two days taking a ten year old middle range CD player and trying to make it to sound really good. But I also have done measurements before and after doing the mod (within reason) and so far it actually confirms that modding really works (if done right). Now, let’s face it, the best measured equipment isn’t necessarily the one that sounds the best, but still, it’s interesting to see what kind of effects different modifications have.My best sounding DAC does not measure as well as some other ones I have. And I have started to get quite the collection.
Will be back with a writeup and test diagrams when I’m finished…
My favorite Media Player, Plex has added a lot of new streaming content. Check it out here.
Over a year ago this guy contacted me to get permission to use this picture for an album cover. I sent him a high res copy and told him that he could use the picture but that he had to send me a copy of the album when it was finished. My guess was I would never hear from him again. But to my surprise I got an email from him yesterday asking for my address and if I wanted the album signed by the artist! Things like this makes me believe in the human being again. I just assumed he would forget to send the album, which is what I probably would do.
“Black Like Me” (John Howard Griffin)
Back in 1961 the author disguises as a black man and experiences all the prejudices in the south.
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