Mods your Pioneer PD S-505 CD Player for better sound quality
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 It will not be just the standard subjective judgment 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 crystal and opamp
But first we need the schematic of the player, so download the Pioneer PD-S505 schematic here.
Ok, let’s look at some stuff we need to do. First, we have to remove the mute transistors. Fewer electronics in the audio path gives better sound quality. The transistors are 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 are 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 headphone opamp if you don’t plan to use it. It’s better to buy an external headphone amplifier instead.
That’s about it for today. Next installment, upgrade the clock to improve jitter numbers.