Hello,
I look for the Philips CD 753,723 schematic or service manual.
I would like to make a transport with this CD.
Can anybody help me?
Thanks
I look for the Philips CD 753,723 schematic or service manual.
I would like to make a transport with this CD.
Can anybody help me?
Thanks
Hi, did you manage to find a copy of this manual? I got quite a few on my links page but not this one and I'm about to modify one for a friend. If you have one, I'd be grateful Thanks 🙂
Could someone tell me what kind of modifications he has made? I'am also very interested in de CD 753.
Thanks a lot
Thanks a lot
Hi, I modded one of these for a friend. They are very very good as std. In fact they sound better than they look like they should.
I replaced the smoother in the psu (+10v before the reg) with much larger 22,000uF Panasonic TSUP's, Built a separate +/-12v regulated supply for the opamp stage and replaced the opamp with a LME49720HA, split the 5v rails for the DAC and fed with 3 independent regulators. I replaced lots of decoupling caps with Rubycon ZA's.
On the transport, I replaced the clock with decent oscillator powered from a low noise reg and replaced several caps with ZA's again.
I'm sure I did something with the elco's in the signal path on the output but I cant remember what!!!
The result was stunning. This player looks like a low end toy but would seriously give some "hi-fi" a run for its money with mods. 😉
I replaced the smoother in the psu (+10v before the reg) with much larger 22,000uF Panasonic TSUP's, Built a separate +/-12v regulated supply for the opamp stage and replaced the opamp with a LME49720HA, split the 5v rails for the DAC and fed with 3 independent regulators. I replaced lots of decoupling caps with Rubycon ZA's.
On the transport, I replaced the clock with decent oscillator powered from a low noise reg and replaced several caps with ZA's again.
I'm sure I did something with the elco's in the signal path on the output but I cant remember what!!!
The result was stunning. This player looks like a low end toy but would seriously give some "hi-fi" a run for its money with mods. 😉
Thanks for your comment. I will replace the opamp with a LM4562 and I recognise many of your mods.
I found a couple of pics showing the mods I did. Clock with decent reg, big caps on the rails, lots of small ZA caps for local decoupling and 3 separate regs on the dac. Oh and the opamp 🙂
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Very impressive. I have still a modification for you. You could remove the "mute" transistors at the output of the opamp. It is known that these transistors influences the sound, produced by the CD player.
It is not necessary to use a couple C. You could bypass the current capacitors. In other words the output of the opamp directly to the tulps.
Its not possible to bypass the DC blocking caps on the output of this player as there is approx 3v dc present
Replacing the OpAmps in my DVD/CD players with LM4562 always had an impressive result.
In one instance I did install DIP sockets so I can roll a few models - and I could compare them fairly easy.
In one instance I did install DIP sockets so I can roll a few models - and I could compare them fairly easy.
Last edited:
No.I think those sound identical - if loaded with higher impedance than 2kohm.
Only when you try to dive headphones with OpAmps (and you push them at higher disipated power) it makes sense to use HA version.
Only when you try to dive headphones with OpAmps (and you push them at higher disipated power) it makes sense to use HA version.
Hi all,
I bought a CD723 for £20 after reading about them on here, I had listened to a Technics thing until then, the 723 is a great improvement in every way.
Thanks Stainless for the link to the service manual much appreciated
I am going to do the Decibel Dungeon mods to it: Modifying a CD player's electronics. this doesn't include the clock mod that UV101 mentions though.
I just know what components look like and am quite good at soldering but I am determined to have a go at the mods.
Jim
I bought a CD723 for £20 after reading about them on here, I had listened to a Technics thing until then, the 723 is a great improvement in every way.
Thanks Stainless for the link to the service manual much appreciated
I am going to do the Decibel Dungeon mods to it: Modifying a CD player's electronics. this doesn't include the clock mod that UV101 mentions though.
I just know what components look like and am quite good at soldering but I am determined to have a go at the mods.
Jim
DC voltage on the output of the opamp
Hello UV101
I measured with my scope no DC on the output of the opamp 4562. Only some noise. So in my opinion it is still worth trying the bypass the output caps. The amplification of this opamp is appr. 1.5. I want to try to increase this amplification to appr. 4. Reason is that my tube amp, with only one tube has an amplification of only 1.
Hello UV101
I measured with my scope no DC on the output of the opamp 4562. Only some noise. So in my opinion it is still worth trying the bypass the output caps. The amplification of this opamp is appr. 1.5. I want to try to increase this amplification to appr. 4. Reason is that my tube amp, with only one tube has an amplification of only 1.
Hi, if there is no DC its worth bypassing the blocking caps for sure. It was a while ago that I modded this player for a friend. I thought I measured 3v DC but I could have been mistaken.
If you are looking to take the player further, you could try bypassing the internal opamp I/V stage on the DAC chip itself. Another easy mod would be to provide a separate +/- PSU for the opamp itself.
My attention is now with THIS!!! 😉
If you are looking to take the player further, you could try bypassing the internal opamp I/V stage on the DAC chip itself. Another easy mod would be to provide a separate +/- PSU for the opamp itself.
My attention is now with THIS!!! 😉
Hi,
sorry for disturb, I want to 'upgrade" my Philips cd753. Some help?(schematic, ..all other infos If is posible please?..what is improvement?some pics?😀
THX in advance.🙂
best regards.
sorry for disturb, I want to 'upgrade" my Philips cd753. Some help?(schematic, ..all other infos If is posible please?..what is improvement?some pics?😀
THX in advance.🙂
best regards.
- Status
- Not open for further replies.