Wednesday, 23 January 2013

Why would you??? CD52 mods!!! SOme Theory!

One of the great things is that these players can be got for next to nothing. I'm trying to make this thread about time rather than boutique products just to see where it ends up. hopefully it will inspire others to discover how good some of the older players actually are. Hopefully my explaining how the power supplies work and are distributed to the various components around the player, it will give others the tools to try the same.

You can draw analogies for what I am trying to do with the 5v rail.

Imagine if you had 8 fridges in your house all on the same circuit as your hifi. You'd constantly hear pops as the pumps start and stop. Now imagine if put all the fridges and each individual hifi component on their own circuit from the fuseboard or better still on their own service supply from the electriciy board via their own dedicated consumer units. Scale that down and to whats inside the CD player and we have a single 5v regulator feeding many critical components, each introducing its own noise to the common supply rail. Obviously the same applies to all the internal rail but for now, I'm concentrating just on the +5v......the rest will come later

Replacement loading gear has arrived!!!

I'm in shock!!!! Exactly 1 week after ordering the loading gear, it arrived from China!

Only took a few seconds to fit and now we have a fully functioning tray 
I cleaned and re greased the teeth and gear with some silicon grease.

I've also been working on the distribution of the +5v rail within the whole player. I stated previously that it would be good to try and seperate the "noise domain" by individually regulating each power supply pin rather than having everything share the same single regulator. In this player, each pin is separated by a feed resistor in order to address this issue (well to a very small degree).

I've now got the details together to seperate the 5 supply pins for the DAC, the digital O/S filter (if it stays) the Decoder, the RAM for the decoder, the SPDIF driver (if it stays) and the CPU. I'll use low noise regs for everything except the CPU which just needs putting in it own noise domain. I'll sort some pictures explaining what I mean a bit later.