Till,
thanks,
was it you who wants to use AD1865 ?
I think the main problem is that it needs 18bit input.
The SAA7345 could provide that, if you find a CDP with that chip...
Put a 220µ/10V Oscon close to the SAA7220 today.
The output stages of the Philips CDPs have 3,4V DC offset
So they need a coupling cap
What about the modified schematic below ?
There is a voltage divider in the feedback loop with one end connected to 6,8V instead to ground.
So DC offset on output is eliminated.
And some gain is provided.
thanks,
was it you who wants to use AD1865 ?
I think the main problem is that it needs 18bit input.
The SAA7345 could provide that, if you find a CDP with that chip...
Put a 220µ/10V Oscon close to the SAA7220 today.
The output stages of the Philips CDPs have 3,4V DC offset
So they need a coupling cap
What about the modified schematic below ?
There is a voltage divider in the feedback loop with one end connected to 6,8V instead to ground.
So DC offset on output is eliminated.
And some gain is provided.
Attachments
I would throw out all parts and start again with a discrete I/V like the ones Rbroer designed. Better do it right directly instead of doing it only half good and needing to work on it a second time. Now don't ask me which thread please.
I think your attitude towards finding information yourself is not very enthousiastic. How do you think we find things ? You can't seriously expect that every thing you ask is served at once on a silver plate....
jean-paul said:
But that's what I want, because I have only one live and do not like to waste it, searching forums.
Seriously, the question is more complex, the garbage of the oversampling DAC has 4x higher frequency, so letting it pass could be more of a problem compared to non os.
I do not like to turn the CD880 into a rat nest, I was lucky enough all the MKPs and the Oscon fitted...
The one and only solution would be to rebuild the whole board including microprozessor.
So I only change all parts for the best I can get and leave the topologie as is.
Then I can compare sound to the external 4chip DAC later.
Thats the only purpose of the modding.
Also unfiltered oversampling would be only an option for the external DAC.
So far:
An externally hosted image should be here but it was not working when we last tested it.
I understand what you mean as I like to work tidy as well. It is not an excuse for leaving a technical less good solution because of tidyness...
Rbroer offers nice PCB's for his discrete I/V stage. No ratsnest whatsoever.
Besides that, why change the parts if you'll build an external DAC anyway ?!?! Better make it analog stage-less and omit the SAA7220 and implement a low jitter clock. Less garbage on the supply lines too. You'll be surprised how much a low jitter clock can do for the soundquality.
This is not more complex, on the contrary. The 176 kHz of os DAC's is more easy to filter than the garbage in non os DAC's ( that's a lot closer to the audible band ). After all it was one of the advantages that came along when oversampling became standard. Simple Bessel filtering instead of brickwall filtering was one of the features that helped to sell oversampling to the consumer...
This is the last reaction you get from me. I don't want to waste my time on people asking questions that all have been covered before just because they're too lazy to do some effort. Good luck with your 4 x parallel TDA1541A that will probably sound better than that dreadful non os TDA1543 ( that you never heard )
jean-paul said:
I understand what you mean as I like to work tidy as well. It is not an excuse for leaving a technical less good solution because of tidyness...
Rbroer offers nice PCB's for his discrete I/V stage. No ratsnest whatsoever.
Besides that, why change the parts if you'll build an external DAC anyway ?!?! Better make it analog stage-less and omit the SAA7220 and implement a low jitter clock. Less garbage on the supply lines too. You'll be surprised how much a low jitter clock can do for the soundquality.
This is not more complex, on the contrary. The 176 kHz of os DAC's is more easy to filter than the garbage in non os DAC's ( that's a lot closer to the audible band ). After all it was one of the advantages that came along when oversampling became standard. Simple Bessel filtering instead of brickwall filtering was one of the features that helped to sell oversampling to the consumer...
This is the last reaction you get from me. I don't want to waste my time on people asking questions that all have been covered before just because they're too lazy to do some effort. Good luck with your 4 x parallel TDA1541A that will probably sound better than that dreadful non os TDA1543 ( that you never heard )
* I want to compare the sound of the standard topologie with that of the external DAC, so I just put same quality parts inside the CD880.
Non os, discrete, tubes maybe, parrallel chips, low jitter clock, all that is for the external, and I will be able to hear the difference and know if it is worth the trouble.
* It is clear that 176kHz is more easy to filter, but what happens if you do not filter ?
176kHz garbage could be more of a problem than 44 kHz.
* I heard the 1543 in os and did not like it.
To my logic it seems that both chips should benefit from non os if they do. So why use the inferior 1543 ?
Also you should know that people have different opinions.
Some like 1543, others 1541.
Some like non os, some don't.
Some prefer S1, others plain 1541
Some love 5532, others 627.
Some trust in Paper in oil, others believe it's crap.
And I definitely do not like the 1543.
Bernhard will beat me because this appears in his pure 1541 thread.
As i learned i need to set the CD PRO to another than default DAC mode. OK. I don´t know which of the modes, and i need to programm a PIC for sending at least [Set Dac mode ??] and [play] as DSA commands to the CD PRO 2.
Or use that damned spdif and a 8412.
As i learned i need to set the CD PRO to another than default DAC mode. OK. I don´t know which of the modes, and i need to programm a PIC for sending at least [Set Dac mode ??] and [play] as DSA commands to the CD PRO 2.
Or use that damned spdif and a 8412.
bad idea, very bad idea
After putting Oscon close to SAA7220, I compared again to CD304.
Still CD304 sounds faster, smoother, more relaxed, while CD880 sounds a little nervous, bass is hard, highs too bright.
After all the mods...
One last thought before killing myself:
What difference is left between these two players
Both CDM1(mkII)
CD304 chip decoupling, CD880 HQ MKP ---> better.
CD304 NE5532 plastic, CD880 NE5532A ceramic ---> better.
Both same coupling cap @ output but CD304 additional silver mica bypass
CD304 cheap electrolytic for SAA7220, CD880 OSCON ---> better.
CD304 cheap electrolytic + KP bypass for opamp decoupling, CD880 MKP
CD304 4556 for headphone amp, CD880 2x4556 parallel
Both plain 1541 chip
Guess what it was ?
I cut six legs
Now the CD880 sounds like heaven
No audible difference between these two so far.
After putting Oscon close to SAA7220, I compared again to CD304.
Still CD304 sounds faster, smoother, more relaxed, while CD880 sounds a little nervous, bass is hard, highs too bright.
After all the mods...
One last thought before killing myself:
What difference is left between these two players
Both CDM1(mkII)
CD304 chip decoupling, CD880 HQ MKP ---> better.
CD304 NE5532 plastic, CD880 NE5532A ceramic ---> better.
Both same coupling cap @ output but CD304 additional silver mica bypass
CD304 cheap electrolytic for SAA7220, CD880 OSCON ---> better.
CD304 cheap electrolytic + KP bypass for opamp decoupling, CD880 MKP
CD304 4556 for headphone amp, CD880 2x4556 parallel
Both plain 1541 chip
Guess what it was ?
I cut six legs
Now the CD880 sounds like heaven
No audible difference between these two so far.
I currently have Marantz CD80 (CDM1/Mk2, 1541a S1 Selection), Philips CD960( CDM1 and swapping in Sa7220p/b & 1541 S1), Arcam delta Cd 70.2 (CDM4/11 and TDA1541 S1 silver Crown) and Rotel RCD855 (CDM4/19 TDA1541a). Without modification they were all sound poor but after mods they sound fantastic, and very close to each other. I certainly like the CD960 most, may be CDM1 makes sound better!..
Cheer
Cheer
They are just very diffrent.
Both have brushless motors (each one diffrent),but CDM 1 is all aluminium cast,even swing arm and lens holder.
You have both at home.
Just put them apart and compare opticly...you will understand.
Bartek
CDM1/MKII is more like better version of CDM 4
CDM 1 is totaly diffrent thing.
Both have brushless motors (each one diffrent),but CDM 1 is all aluminium cast,even swing arm and lens holder.
You have both at home.
Just put them apart and compare opticly...you will understand.
Bartek
CDM1/MKII is more like better version of CDM 4
CDM 1 is totaly diffrent thing.
Re: bad idea, very bad idea
CD880 uses one NE5532 per channel for the headphones.
Two opamps in each chip are paralleled.
And that does not sound as good as one opamp alone.
Thats why I cut 6 legs, 3 per chip.
Beside beeing happy, having found the error, I find that very interesting...
Bernhard said:Guess what it was ?
I cut six legs
CD880 uses one NE5532 per channel for the headphones.
Two opamps in each chip are paralleled.
And that does not sound as good as one opamp alone.
Thats why I cut 6 legs, 3 per chip.
Beside beeing happy, having found the error, I find that very interesting...
I do not believe this
First, There is another problem, my analyzer does not show much with the -60dB signal.
And I have no preamp, so I misused my relais volume control by turning a buffer into a 20dB amp.
Now there is some 100Hz noise, but it won't affect the result too much.
The real problem is the result itself, before posting I need to recheck it, but maybe take a seat...
First, There is another problem, my analyzer does not show much with the -60dB signal.
And I have no preamp, so I misused my relais volume control by turning a buffer into a 20dB amp.
Now there is some 100Hz noise, but it won't affect the result too much.
The real problem is the result itself, before posting I need to recheck it, but maybe take a seat...
O = below noise floor (-65dB because of bad preamp)
CDP = CD880
SAA7220A
S1 Silvercrown
K2 -56,4 K3 -44,9 K4 -57,8 K5 -53
S1 CD880
K2 -56,6 K3 -46,3 K4 -58,6 K5 -53
1541 CD304 1
K2 -56 K3 O K4 -57,5 K5 -60,6
1541 CD304 2
K2 -56,2 K3 -46,2 K4 -58 K5 -52
1541 CD650
K2 -57,3 K3 -58,2 K4 -59,3 K5 O
1541A
K2 -56,2 K3 -43,1 K4 -57,6 K5 -50,4
SAA7220B
S1 Silvercrown
K2 O K3 -58,1 K4 -62,4 K5 -53,3
S1 CD880
K2 O K3 -57,5 K4 -62,6 K5 -62,5
1541 CD304 1
K2 O K3 -60,9 K4 -62,6 K5 -58,5
1541 CD304 2
K2 O K3 -57,2 K4 -62,5 K5 -57,7
1541 CD650
K2 O K3 -56 K4 -62 K5 -63,5
1541A
K2 O K3 O K4 -62,7 K5 -55,9
For best sound, shouldn't the spectrum go down continiously with higher orders ?
Then my choice would be 1541 from CD650 with SAA7220A
CDP = CD880
SAA7220A
S1 Silvercrown
K2 -56,4 K3 -44,9 K4 -57,8 K5 -53
S1 CD880
K2 -56,6 K3 -46,3 K4 -58,6 K5 -53
1541 CD304 1
K2 -56 K3 O K4 -57,5 K5 -60,6
1541 CD304 2
K2 -56,2 K3 -46,2 K4 -58 K5 -52
1541 CD650
K2 -57,3 K3 -58,2 K4 -59,3 K5 O
1541A
K2 -56,2 K3 -43,1 K4 -57,6 K5 -50,4
SAA7220B
S1 Silvercrown
K2 O K3 -58,1 K4 -62,4 K5 -53,3
S1 CD880
K2 O K3 -57,5 K4 -62,6 K5 -62,5
1541 CD304 1
K2 O K3 -60,9 K4 -62,6 K5 -58,5
1541 CD304 2
K2 O K3 -57,2 K4 -62,5 K5 -57,7
1541 CD650
K2 O K3 -56 K4 -62 K5 -63,5
1541A
K2 O K3 O K4 -62,7 K5 -55,9
For best sound, shouldn't the spectrum go down continiously with higher orders ?
Then my choice would be 1541 from CD650 with SAA7220A
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