Jacken's Blog

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