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.
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.
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!!!
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