I have a CD723 with all the "Chris Found" mods plus:
KC-7,
AD826 I/V
Schottky PSU diodes
Separate transformer with emitter follower type power supplies for the OpAmp and DAC (cut down version of the Audionote PSU).
Servo 11V is still supplied off the original unregulated supply.
Output caps 22uF 63V FCs bypassed with 10nF Wima polypropylenes
Chassis damping
In varying amounts, most of the mods made improvements to the sound of the player. However it is still some way behind my lightly modified Arcam Alpha+ player (Trichord clock and a few component upgrades) and a long way behind my friend's Cambridge Audio CD2, both of which are 10+ years old. I reckon the CD723 is comparable with a decent modern £400 CD player.
Any suggestions to make the CD723 better, or have I reached the limit with this very cheap machine???
KC-7,
AD826 I/V
Schottky PSU diodes
Separate transformer with emitter follower type power supplies for the OpAmp and DAC (cut down version of the Audionote PSU).
Servo 11V is still supplied off the original unregulated supply.
Output caps 22uF 63V FCs bypassed with 10nF Wima polypropylenes
Chassis damping
In varying amounts, most of the mods made improvements to the sound of the player. However it is still some way behind my lightly modified Arcam Alpha+ player (Trichord clock and a few component upgrades) and a long way behind my friend's Cambridge Audio CD2, both of which are 10+ years old. I reckon the CD723 is comparable with a decent modern £400 CD player.
Any suggestions to make the CD723 better, or have I reached the limit with this very cheap machine???
Konnichiwa,
Hmmm.
I hope it is well implemented. I would expect the layout to be critical, much more so than the actual circuit.
Why? You like bad sound?
Hmmm. Nothing wrong with that, but again implementation is critical.
Why? You like bad sound?
In what sense?
Yes. Analyse the Circuit. identify the weaknesses and address them. You seem to have left most of the in place, the same style it is often done by "boutique" modders who like sell expensive modules and pretend that an excellent clock and analogue stage will makie a world class player out of any mediocre piece of rubbish.
I don't think so.
Sayonara
Dave S said:
Hmmm.
Dave S said:
I hope it is well implemented. I would expect the layout to be critical, much more so than the actual circuit.
Dave S said:
Why? You like bad sound?
Dave S said:
Hmmm. Nothing wrong with that, but again implementation is critical.
Dave S said:
Why? You like bad sound?
Dave S said:
In what sense?
Dave S said:
Yes. Analyse the Circuit. identify the weaknesses and address them. You seem to have left most of the in place, the same style it is often done by "boutique" modders who like sell expensive modules and pretend that an excellent clock and analogue stage will makie a world class player out of any mediocre piece of rubbish.
Dave S said:
I don't think so.
Sayonara
Dave S said:
Hi Dave,
You could try the OPA2604 or the OP275 for IV.
Jung like regulators seem to better suited for the analog stages in my experience.
A balanced power 1:1 transformer improved the sound of my Philips CD931.
Ultrasoft recovery diodes worked better for me, but this is clearly player dependent as all mods. In the Philips CD650 I heard a big difference, in the CD931 not.
Konnichiwa,
Actually, you can. Here is what is wrong with the CD-720/21/22/23:
1) Powersupply - complete joke. Fit seperate transformers/supplies for Analogue Stage & DAC (+/-12V & 5V), one for the Servo circuitry (+/-12V), one for the clock (5V) - use the basic Tent Audio Module - hard to implement it wrong if you use a fully insulated supply, fit correctly & forget and one (5V - might be 3.3V on the later verions) Supply for the main CD processor.
Build well implemented and de-noised supplies and clean up the original supply to only supply "utility" digital circuitry (uP/Display/Remote etc.). All the transformers used to supply especially the digital section should be chosen for minimal leakage between secondary and earth and suitably phased/ploarised to minimise further any leakage. Then add an external 1:1 insulation transformer and filter, non of this needs a lot of power.
2) Chassis - complete joke. For a minimum fit a serious solid wood bottom plate (spruce plywood) and fit some decoupling feet like the String Suspension thingies you get. Add solid hardwood sidecheeks and a plywood rear panel, plus a nice solid vented top cover made from thin spruce ply, for fun make the vent openings in the shape of Violin Vents. C37 laquering of wood and PCB's are optional.
3) Fit a nice superfast Op-Amp (LM6182 is still my choice) in the analog stage (more or less original circuit adjusted for 2mA Full Scale Current), no capacitor in the feedback loop and follow by a simple low impedance 1st Order LPF (I used 100R/15..22nF IIRC) and a suitable (passive) offset adjustment to get rid of the output offset.
Now the above can be done well on a fairly tight budget, within the existing case so on. For more extreme versions a string suspended drive for a toploader might be worth a try.
The Digital Filter and DAC in the CD-723 are "good enough for CD", if you make sure to eliminate the other problems.
Sayonara
sreten said:
Actually, you can. Here is what is wrong with the CD-720/21/22/23:
1) Powersupply - complete joke. Fit seperate transformers/supplies for Analogue Stage & DAC (+/-12V & 5V), one for the Servo circuitry (+/-12V), one for the clock (5V) - use the basic Tent Audio Module - hard to implement it wrong if you use a fully insulated supply, fit correctly & forget and one (5V - might be 3.3V on the later verions) Supply for the main CD processor.
Build well implemented and de-noised supplies and clean up the original supply to only supply "utility" digital circuitry (uP/Display/Remote etc.). All the transformers used to supply especially the digital section should be chosen for minimal leakage between secondary and earth and suitably phased/ploarised to minimise further any leakage. Then add an external 1:1 insulation transformer and filter, non of this needs a lot of power.
2) Chassis - complete joke. For a minimum fit a serious solid wood bottom plate (spruce plywood) and fit some decoupling feet like the String Suspension thingies you get. Add solid hardwood sidecheeks and a plywood rear panel, plus a nice solid vented top cover made from thin spruce ply, for fun make the vent openings in the shape of Violin Vents. C37 laquering of wood and PCB's are optional.
3) Fit a nice superfast Op-Amp (LM6182 is still my choice) in the analog stage (more or less original circuit adjusted for 2mA Full Scale Current), no capacitor in the feedback loop and follow by a simple low impedance 1st Order LPF (I used 100R/15..22nF IIRC) and a suitable (passive) offset adjustment to get rid of the output offset.
Now the above can be done well on a fairly tight budget, within the existing case so on. For more extreme versions a string suspended drive for a toploader might be worth a try.
The Digital Filter and DAC in the CD-723 are "good enough for CD", if you make sure to eliminate the other problems.
Sayonara
sreten said:
I simply don't care. My bog standard Cambridge Audio
CD4SE is miles better than any modded cheap CD player,
tubes added or not, and as far as I'm concerned thats it.
If you don't care why react in this thread ? You can't compare apples and pears but there are really a lot of possibilities with cheap cdplayers. Especially if you dont like to watch tv in your spare time and have a soldering tool waiting.
For bog standard more or less expensive cdplayers without needed work you're on the wrong forum
Besides that there are plenty expensive cdplayers with excellent build quality that sound absolutely mediocre. The fun with DIY can be making a very good cdplayer with a cheap basic model and some hard earned knowledge.I don't want to challenge you but your remark "miles better than any modded cheap CD player" is like walking on thin ice.
jean-paul said:If you don't care why react ? You can't compare apples and pears but there are really a lot of possibilities with cheap cdplayers. Especially if you dont like to watch tv in your spare time and have a soldering tool waiting.
For bog standard more or less expensive cdplayers without needed work you're on the wrong forum
I don't want to challenge you but your remark "miles better than any modded cheap CD player" is walking on thin ice.
Except the CD4SE is allegedly accepted to be a "giant killer".
(At ~ twice the cost of a budget CD player at the time.)
IMO if you want the best don't make it difficult for yourself.
You can improve a cheap CD player, this I'm not arguing.
But you can't IMO mod a basic CD player into the "ultimate".
What I'm suggesting is take a good / very good CD player and
adding mods that should improve matters is surely easier than
trying to take a cheap (but more to the point average design)
CD player to somewhere it will eventually refuse to go.
sreten.sreten said:
Who said so?!
You should take a listen to my old Marantz CD52 SE with internal TDA1543 NOS Dac and dedicated trafo/PSU.
And Tent clock.
Well, yes, it's useless to loose much time on a player with a bitstream Dac (like my Marantz), but you can easily do something very special out of it.
THIS is giant killer, miles ahead of your BUDGET Cambridge CD4SE.
And I spent much less money than you, with all this.
Deam it, these days people use "giant-killer" and "high-end" too easilly, banalizing this words.
You haven't heard anything yet.
carlosfm said:You should take a listen to my old Marantz CD52 SE with internal TDA1543 NOS Dac and dedicated trafo/PSU.
And Tent clock.
Well, yes, it's useless to loose much time on a player with a bitstream Dac (like my Marantz), but you can easily do something very special out of it.
I wonder what the results would be like if the same level of attention was given to the original Bitstream DAC????
Cost vs benefit
What are those "high quality build practices"?
And
Who said anything about "bypassing" them?
Looking at Kuei Yang Wang's recommendations, I don't see any evidence of short-cuts. Every aspect of the player's build/design is addressed.
How do you know this?
"Allegededly accepted whom"?
A "giant killer" at twice the cost of a budget CDP???
Is this a contradiction?
The giants that it is killing must be even more expensive. How did it manage to do this? - By somehow bypassing the "high quality build practices" of the very expensive machines??
What is "the best" and how do you know when you've got it?
Doing that which is difficult is what this forum is all about. For most of us, there is a certain satisfaction in taking a machine with humble beginnings and turning it into something much better. We are not bypassing high quality build practices - we are trying to identify the short-cuts and cost cutting that the manufacturer has made, and then address those items.
How does one know that the designer of the more expensive CDP has got it right? These players are still built to a price point and will still be compromised in some way. Yes, the more expensive machine may sound better than the unmodded budget one - but once the modding process starts, a lot more innovative ideas and best sounding or engineering practices can be implemented in the more basic models. For instance, a mid priced CDP may have some reasonable quality componentry or sections. It is less likely that you would rip these out to replace them with the best options. If you do rip them out, then you have wasted you money in the first place by paying for their inclusion in your CDP. It is also possible that the more expensive machines rely more heavily on the selection of specific components and less on the critical layout.
sreten said:
What are those "high quality build practices"?
And
Who said anything about "bypassing" them?
Looking at Kuei Yang Wang's recommendations, I don't see any evidence of short-cuts. Every aspect of the player's build/design is addressed.
sreten said:
How do you know this?
sreten said:
"Allegededly accepted whom"?
A "giant killer" at twice the cost of a budget CDP???
Is this a contradiction?
The giants that it is killing must be even more expensive. How did it manage to do this? - By somehow bypassing the "high quality build practices" of the very expensive machines??
What is "the best" and how do you know when you've got it?
Doing that which is difficult is what this forum is all about. For most of us, there is a certain satisfaction in taking a machine with humble beginnings and turning it into something much better. We are not bypassing high quality build practices - we are trying to identify the short-cuts and cost cutting that the manufacturer has made, and then address those items.
How does one know that the designer of the more expensive CDP has got it right? These players are still built to a price point and will still be compromised in some way. Yes, the more expensive machine may sound better than the unmodded budget one - but once the modding process starts, a lot more innovative ideas and best sounding or engineering practices can be implemented in the more basic models. For instance, a mid priced CDP may have some reasonable quality componentry or sections. It is less likely that you would rip these out to replace them with the best options. If you do rip them out, then you have wasted you money in the first place by paying for their inclusion in your CDP. It is also possible that the more expensive machines rely more heavily on the selection of specific components and less on the critical layout.
Forunately for all of us, the designer of the CD4SE seems keener on promoting DIY modding than Sretin.
Actually, the CD4SE was not really suitable for upgrading (electronically) as it was already extensively 'modded', hence the excellent sound quality. Much better for a DIYer to start with something like the CD723 which is basic and cheap!
As ever the last words should be 'each to his (or her) own!'
Actually, the CD4SE was not really suitable for upgrading (electronically) as it was already extensively 'modded', hence the excellent sound quality. Much better for a DIYer to start with something like the CD723 which is basic and cheap!
As ever the last words should be 'each to his (or her) own!'
Fin said:
Of course it was.
And I have two independent RCA outs on the player, I can even A/B.
There's no comparison between a bitstream Dac, the better that it may be, and a good multibit Dac.
Yes, the TDA1543 is good.
Forget the specs, well done it's very good.
Bitstream Dacs always sound undynamic to me.
I'm not trying to give anybody a hard time! Life does that well enough for all of us.
But the original question was how could the CD723 be modified to sound better. You introduced the subject of starting off with a 'better' product. That's fine if the person asking the question was enquiring about how to get a good CDP from scratch. But he already has his CD723 and has spent time and money on it.
For my part, I was just saying that having heard the CD4SE and a modified CD723, I would prefer to go with the CD723 from a modders point of view.
If I just wanted to have a really good sounding CDP without opening the case, I would take your suggestion and try to hunt out a CD4SE although they are rare as hens teeth and I doubt any owners are prepared to sell theirs - would you?
I also speak from experience in saying that the CD4SE is not a good CDP for modding!
I greatly respect your vast knowledge of speaker building and if you came on a thread about speakers and put me right, I wouldn't think that you were giving me a hard time
But the original question was how could the CD723 be modified to sound better. You introduced the subject of starting off with a 'better' product. That's fine if the person asking the question was enquiring about how to get a good CDP from scratch. But he already has his CD723 and has spent time and money on it.
For my part, I was just saying that having heard the CD4SE and a modified CD723, I would prefer to go with the CD723 from a modders point of view.
If I just wanted to have a really good sounding CDP without opening the case, I would take your suggestion and try to hunt out a CD4SE although they are rare as hens teeth and I doubt any owners are prepared to sell theirs - would you?
I also speak from experience in saying that the CD4SE is not a good CDP for modding!
I greatly respect your vast knowledge of speaker building and if you came on a thread about speakers and put me right, I wouldn't think that you were giving me a hard time
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