Jacken's Blog

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.

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

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…