Philips CD723 MOD

[huangyong 0]

Read about modding at this website decdun quite sometime ago. Very curious to try out, want to find out whether a sub$100 CD player can be modded to beat the $500 CDP.

 

Happen to know one hifi kalang guni guy, and got a CD723 at price of 40 bucks... quite a steal, but lens a bit kapuk...

Later i tried all the mod shown in the website, WOW.. it improved by a big margin, however, still cant beat the beast out there...

So decided to further mod it, this time round no guide from anywebsite, just D I Y.

started off by doing a lot of readings, found out TDA1454 chip need some clean & steady 5V supply, and DIYers out there are using TL431 to obtain 5V. I read the datasheet and design a vey simple ciruit :

 

Unregulated DC --> LM7809 ---> RC ----> TL431

 

TL431 comes in different package, i chose the DIP8 type because it's easier to work with. The caps are nichicon fine gold 470uF 35V, elna cerafine 470uF 16V and some other poly generic caps.

 

The circuit is very easy to implement on a veroboard using point-to-point method, i finished it within 15 mins. After done, with excitement, i quickly installed in my new "5V PSU FOR DAC" and anticipating good sound. To my horror.. the CD transport failed to function, produced some "crack..crack" kind of sound.

 

i have no choice, but have to cancel my date (today is Saturday<_<) and did troubleshooting for hours. Tracing the PCB track.. and ahh... found the problem.....

PLEASE TAKE NOTE IF YOU ARE DOING SIMILAR MOD ON CD723: the player 5V(originally using LM7805) supply shared by DAC and CD transport. My new 5V supply was set at less than 100mA, of course it won't work!!duh!! then i made another stand alone supply to supply 5V to the transport..

 

Pop in a CD and ...WOOOO......sound really nice..

 

here're 2 pics:

 

 

 

 

 

[Q00 0]

You cancelled a date? Hardcore man.. hope the improvement in sound is worth it!

[N3w_Typ3 0]

I wonder is there any improvement for mine CD 634.

[huangyong 0]

Too bad I don't have program to sketch out the schematic. Just switched to Mac and all the engineering software will not run in Mac OS.

 

New_type3, i think generally improving the power supply will increase the performance of the player. Why don't you take a pic to show us your player? (nude pic pls) and we'll see how to improve it..

 

 

[N3w_Typ3 0]

New_type3, i think generally improving the power supply will increase the performance of the player. Why don't you take a pic to show us your player? (nude pic pls) and we'll see how to improve it..

 

Sure thing once I am free.

[av98m 0]

You cancelled a date to poke around inside a cd player?.......*vomits blood and dies*

[heady 0]

huangyong, you are one dedicated diy-er. *Salute*

[Absolute0 0]

You deserve to be ditched. LOL, just joking. Your passion in diy is admirable, to say the least.

[huangyong 0]

wow... all those comments!!! just tell you that I am not a saint in DIY.. don't carry me so high.. I just don't feel good going out when one of my toys is broken..

 

anyway..my next stage is to remake the analog out section.. then followed by clock upgrade.. and that's it. last stage will be bringing to someone's place to compare.. then review..

[N3w_Typ3 0]

haah coolz sia but I dunno how to DIY so even if I need to add in a extra power supply I think I need someone to do it. lolz cos I intend to stay with this player for a very long time.

 

Hmm how much is to add a extra supply board into it and chaning the power plug into the 3 pins type

Just asking first !

[huangyong 0]

after thinking, it takes too much hassle to make another stand alone analog stage, not worth it for a $40 bucks cd player, may be will do it when make my own CDP.

Still feel itchy to further mod it but again lazy...

Suddenly thought of I have done one standalone voltage regulator board with virtual ground sometime ago, why not make good use of it??!!

 

so open up the player.. take put the board.. identify the power lines, and trace and sketch the circuit, did some planning.. start desoldering... here i have to complaint Philips make very lousy quality PCB board.. They are not DIY friendly at all!!! it copper tracks start coming out after desolder.. WT*.. end up all point to point joins..

 

another thing i need to point out is , Philips really do all the cheap circuit tricks to save cost for this low end model!!~!@#$%^&*

but again..this is low end model.. what to expect..

 

so tapped up the on board power and 6 wires out from the board:

in +, -, Gnd

out +, - vGnd

 

quickly hooked up the regulator board and power it ON with anticipation.. for smokes.. LOL... luckily nothing happen, thank God

 

immediately measure the volatge, WoW.. d*mn accurate, 11.95V at each rail.. so the power supply is +/- 11.95V.

 

here's some insights about this analog stage power MOD.

 

before mod, the voltage is UNREGUALTED, and it shared ground with the rest of the CD player. and somehow i couldn't install audiophile quality opamps such as opa627, opa637 and AD797. whenever i put them in, it sounds like distorted and saturated.. all tha noise..

 

however, cheap player meant to use cheap opamps... hahaha.. it accepts opa2134, opa2227 , NE5532, op275 and work just fine.. I am still confused how this could happen.

 

identified the disease, the cure is to have a good seperate power supply for the opamp.

what i already have is a voltage regulator board made of LM78/7912, and opamp virtual ground. The benefit of this virtual ground is to seperate the analog out from the rest, thus helps to reduce noise.

 

after the simple mod, i tried 2 high-end opamp, opa627 x 2 and AD797 x 2

 

the SOUND:

 

OPA627, i played classical and pop music. the sound is full and dark.. a bit too laidback for my taste. definition is very good, sound smooth. imaging is good but soundstage is restricted compared to AD797. Bass is of course not an issue for this drummer. IMHO, the dac's signature is dark sounding, so putting in a laidback opamp makes it bad.

 

AD797, a very lively opamp, immediately i starts to enjoy the playback of violin concerto, very involving. one thing to take note is the high, it's smooth, not rolled off yet not piercing. mid is just Ok to me. bass weight is there on my rogers, consider quite Ok for a bookshelf.. sondstage is better than opa627 but imging is not as good.

 

those who is currently using Philips CD723 or Marantz CD4000 should consider this power supply mod, for it's price, the C/P is good.

cost:

1x board $1

2x 3300uF 35V Rubycon Caps $3

2x 1000uF 25V Elna Caps $1

2x Connector $1.40

3x 1% resistor $0.30

2x 1N4002 diode $0.20

1x DIP-8 socket $0.40

1x NE5532 opamp $1.50

2x 1uF poly caps $1

2x LM78/7912 $2

 

works out to be just xxxx.xxxx.. do your own sum..

 

 

[huangyong 0]

New_type, just realize u replied.. the external power supply board shouldn't be expensive, as long as don't use exotic caps like blackgates.

power plug to 3 pin type is cheap, but need a lot of hard work, need to cut the casing.

[N3w_Typ3 0]

New_type, just realize u replied.. the external power supply board shouldn't be expensive, as long as don't use exotic caps like blackgates.

power plug to 3 pin type is cheap, but need a lot of hard work, need to cut the casing.

Haha I am still deciding what to do with it, it's either I leave it as it is then when got more budget get a better player or mod this player to sound better and then keep at this setup for a few more years to go because I don't really spent alot of time listening to my setup these days so I need to consider it first.

 

haha the price is good but tell me also no use because I don't know how to DIY lolx

 

plus this CDP lens is still very strong, hhaha

[huangyong 0]

New_typ3, i think you should buy a new CDP la.. this philips low end CDP sucks.. i mod it is to learn electronics and prepare me for my bigger project. my ultimate goal is to build my CDP using DVD-ROM.

[N3w_Typ3 0]

New_type, just realize u replied.. the external power supply board shouldn't be expensive, as long as don't use exotic caps like blackgates.

power plug to 3 pin type is cheap, but need a lot of hard work, need to cut the casing.

Haha I am still deciding what to do with it, it's either I leave it as it is then when got more budget get a better player or mod this player to sound better and then keep at this setup for a few more years to go because I don't really spent alot of time listening to my setup these days so I need to consider it first.

 

haha the price is good but tell me also no use because I don't know how to DIY lolx

 

plus this CDP lens is still very strong, hhaha

haha was thinking for the same thing, if I wanted to get was looking at MF X-ray player but haha I have no idea how much it cost.