After dusting my old Magnavox CDB650 and solving some problems, with the help of this wonderfull forum, I was ready for some listening.
At the beggining things were not looking very promising so I changed most all caps from the main board and also shortened the leads of the bit caps under the DAC. Things got much better but after some time I had problems with the drive not wanting to read the whole cut and was kicking out most of the times.
So I changed all the caps at the servo board underneath the CD drive. Well that did it.
Before going on I will say that all the caps had been changed about 15 years ago to good quality Panasonics HF and HFS with a couple of other brands. I was surprised to find some of caps leaking some green stuff (Panasonics). This has happened also on other gear, so don't take it for granted that if it is a P they are OK.
Well, much to my surprise the sound has changed to an exceptional one remainding me of analog days and in some ways even better. Huge sound stage and very deep plus lots of detail. Now of course I have better amplification so this also helps.
My amazement is that I can hint that there is a lot more than can be had from this chip, since I still hear details that are not fully resolved plus a certain lack of bass and HF could be better.
A general description of the actual CDP is that it has been Poogeed by Jung article in AA. Still an oversampled design using decoder SAA7210 and digital filter SAA7220 plus a TDA1541A S1 DAC.
The I/V is per Jung, if I remember this is a AD844 CF Opamp, but I'm not using a buffer so the signal goes directly from the I/V opamp stage through the output caps to the line amp. This analog section is fed by two Jung/Sultzer regs using a separate PSU. That pretty much sums it up.
I'm currently bulding a couple of PSU to feed the DACs this I assume will help the overall sound.
My main concern at this point is how can I deal with the laid back bass and better the HF.
I do have some ideas that have been posted on this forum such as the Rbroer analog stage and the Kuei OPA660 or the Adagio vacumm stage. Hopfully one of these may bring back the missing balance.
Any suggestions???
At the beggining things were not looking very promising so I changed most all caps from the main board and also shortened the leads of the bit caps under the DAC. Things got much better but after some time I had problems with the drive not wanting to read the whole cut and was kicking out most of the times.
So I changed all the caps at the servo board underneath the CD drive. Well that did it.
Before going on I will say that all the caps had been changed about 15 years ago to good quality Panasonics HF and HFS with a couple of other brands. I was surprised to find some of caps leaking some green stuff (Panasonics). This has happened also on other gear, so don't take it for granted that if it is a P they are OK.
Well, much to my surprise the sound has changed to an exceptional one remainding me of analog days and in some ways even better. Huge sound stage and very deep plus lots of detail. Now of course I have better amplification so this also helps.
My amazement is that I can hint that there is a lot more than can be had from this chip, since I still hear details that are not fully resolved plus a certain lack of bass and HF could be better.
A general description of the actual CDP is that it has been Poogeed by Jung article in AA. Still an oversampled design using decoder SAA7210 and digital filter SAA7220 plus a TDA1541A S1 DAC.
The I/V is per Jung, if I remember this is a AD844 CF Opamp, but I'm not using a buffer so the signal goes directly from the I/V opamp stage through the output caps to the line amp. This analog section is fed by two Jung/Sultzer regs using a separate PSU. That pretty much sums it up.
I'm currently bulding a couple of PSU to feed the DACs this I assume will help the overall sound.
My main concern at this point is how can I deal with the laid back bass and better the HF.
I do have some ideas that have been posted on this forum such as the Rbroer analog stage and the Kuei OPA660 or the Adagio vacumm stage. Hopfully one of these may bring back the missing balance.
Any suggestions???
apassgear said:
My main concern at this point is how can I deal with the laid back bass and better the HF.
Any suggestions???
It's only based on what I've heard from Elso, but maybe you should try TDA1543?😉
Re: Re: TDA1541A S1 come back!!!
Hi Peter,
What did I say before thinking first?....
Bass slam depends on analog powersupply, including the one feeding the TDA1543, clock in the CDP, and circuitry used for IV-converter and outputbuffer. Besides discrete circuit I am using hefty push-pull outbuffers in the IV and output.
It is my all-out attempt to get the same bass slam from the CD as from the LP.
I realize I only partly succeeded...
HF I believe is better from the TDA1543 and bass also....
Kuei Y.W. I realize this is my own personal taste as heard on my set including K-hornspeakers. I know you don't concur... 😉
Peter Daniel said:
Hi Peter,
What did I say before thinking first?....
Bass slam depends on analog powersupply, including the one feeding the TDA1543, clock in the CDP, and circuitry used for IV-converter and outputbuffer. Besides discrete circuit I am using hefty push-pull outbuffers in the IV and output.
It is my all-out attempt to get the same bass slam from the CD as from the LP.
I realize I only partly succeeded...
HF I believe is better from the TDA1543 and bass also....
Kuei Y.W. I realize this is my own personal taste as heard on my set including K-hornspeakers. I know you don't concur... 😉
Elso,
After reading your post I imagine that my main problem is not using an output buffer.
I understand of course that bettering the other aspects will still improve things.
Coming back to the I/V and buffer what would be your suggestion taking in consideration that I have at hand the following Opamps?
AD8620AR
AD825AR
AD811JR
AD827
LM6172IM
LM6181IM8
After reading your post I imagine that my main problem is not using an output buffer.
I understand of course that bettering the other aspects will still improve things.
Coming back to the I/V and buffer what would be your suggestion taking in consideration that I have at hand the following Opamps?
AD8620AR
AD825AR
AD811JR
AD827
LM6172IM
LM6181IM8
Peter,
Using 1543 would mean to redo all the PCB, I dont think even that the number of pins are the same.
Beenig an old and trashy CDP I dont think it's a good idea to to put much work on it since the remaining life of the lasser is dificult to predict. So in this case I only want to test the potential of the DAC and use it until the lasser dies and maybe in a future redo the PCB using another CDdrive but using the same DAC.
Regarding the 1543 I would like to test it but I'll have to wait until the end of the year. I have read a lot about it on this forum and looks very promising
Using 1543 would mean to redo all the PCB, I dont think even that the number of pins are the same.
Beenig an old and trashy CDP I dont think it's a good idea to to put much work on it since the remaining life of the lasser is dificult to predict. So in this case I only want to test the potential of the DAC and use it until the lasser dies and maybe in a future redo the PCB using another CDdrive but using the same DAC.
Regarding the 1543 I would like to test it but I'll have to wait until the end of the year. I have read a lot about it on this forum and looks very promising
Outputbuffer
Hi Tony, I would use none of the above.
Sonnya's circuit comes closest to mine:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=1794&highlight=sonnya+AND+cascode
😉
apassgear said:
Hi Tony, I would use none of the above.
Sonnya's circuit comes closest to mine:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=1794&highlight=sonnya+AND+cascode
😉
apassgear said:
You don't really have to redo anyting. Here's how complete TDA1543 circuit is looking like, including PS: 1 chip, 5 resistors and 2 caps. You can build it in one hour😉
Even without reclocking it sounds amazingly good. A friend of mine listening to it, commented that it's better than Copland and I know for myself, that it's better than Bel Canto.
Attachments
You are a good salesman Peter. Do you work for Philips? (just kidding).
As much as you show on the pic this is a much simppler circuit than what Elso suggested as an output stage!!
Which circuit are you following?
Is the DAC a special selection?
As much as you show on the pic this is a much simppler circuit than what Elso suggested as an output stage!!
Which circuit are you following?
Is the DAC a special selection?
Elso,
Thanks for the input but your suggestion is far reaching for me, I'm looking for something simple and good, not a discreet opamp.
Any further suggestion in lieu???
Thanks for the input but your suggestion is far reaching for me, I'm looking for something simple and good, not a discreet opamp.
Any further suggestion in lieu???
Mlloyd,
Thanks for the reference, I've seen this thread before, but strange I don't see a Joko's full schematic.
I wonder if I should use a simpler approach, something like Kuei proposal with the OPA660, but unfortunately I don't have this Opamp.
Thanks for the reference, I've seen this thread before, but strange I don't see a Joko's full schematic.
I wonder if I should use a simpler approach, something like Kuei proposal with the OPA660, but unfortunately I don't have this Opamp.
CDP Mods
Hi Tony,
One of the first things I did to my Sony was replacing opamps by AD827, 12 years ago! Then I added a discrete output booster. Very simple circuit by Walt Jung using only two transistors. I continued and eventually made a complete discrete opamp.
You can use BUF634 but I found it less transparant than a discrete buffer.
😉
Interestingly BUF634 is used by Wadia, Madrigal & Linnenberg.🙄
Of the list of opamps you mentioned I tried the AD811 as IV-converter only. In my Philips CD-650 I tried the LM6171 too in the original position as IV-converter and outputbuffer.
I liked the AD827 more in this player. I have a dislike for the AD825.😉
AD827 is obsolete now and succeeded by AD826.😎
apassgear said:
Hi Tony,
One of the first things I did to my Sony was replacing opamps by AD827, 12 years ago! Then I added a discrete output booster. Very simple circuit by Walt Jung using only two transistors. I continued and eventually made a complete discrete opamp.
You can use BUF634 but I found it less transparant than a discrete buffer.
😉
Interestingly BUF634 is used by Wadia, Madrigal & Linnenberg.🙄
Of the list of opamps you mentioned I tried the AD811 as IV-converter only. In my Philips CD-650 I tried the LM6171 too in the original position as IV-converter and outputbuffer.
I liked the AD827 more in this player. I have a dislike for the AD825.😉
AD827 is obsolete now and succeeded by AD826.😎
Peter Daniel said:
Wow! that's so simple.
I wonder about the detail of this circuit, please... :>
Peter,
Thanks for the posted circuits.
I understand that the 1543 is considered by Philips as a budget DAC but I wonder if there are some special selections?
Heard also you built a multichip version a la Kusunoki but you seem to preffer the single chip?
Thanks for the posted circuits.
I understand that the 1543 is considered by Philips as a budget DAC but I wonder if there are some special selections?
Heard also you built a multichip version a la Kusunoki but you seem to preffer the single chip?
I requested some OPA660 to try TL I/V but they are out of stock.
So for the moment I intend to try the AD811 I/V. Could you point me to a circuit using this implementation?
Coming back to the CDB650 I can report that with further brake-in the bass is coming in nicely but somewhat rounded at the low end. I also realized that the CDP is inverting so changed polarity to the speaker cables.
----------------------------------------
I noted also on the bass speaker certain low freq movement which is related to the sound but certainly not actual signal. The movement is like what you have on analog with disc wrapage.
My first impresion is that it is a PSU voltage IM.
So for the moment I intend to try the AD811 I/V. Could you point me to a circuit using this implementation?
Coming back to the CDB650 I can report that with further brake-in the bass is coming in nicely but somewhat rounded at the low end. I also realized that the CDP is inverting so changed polarity to the speaker cables.
----------------------------------------
I noted also on the bass speaker certain low freq movement which is related to the sound but certainly not actual signal. The movement is like what you have on analog with disc wrapage.
My first impresion is that it is a PSU voltage IM.
apassgear said:
Sometimes budget chips are better, because of simpler design. And I found out, that simple circuits usually work better. I tried 4 chips and 2 chips in parallell with different voltages and clearly a single one with 5V supply works best. More resoulution, smoother and relaxed. I also tried Lundahl transformers at the output, but they definitely degraded the sound. A friend of mine tried those transformers at the output of oversampling DAC (SF DAC1) and he was raving about them.
Actually I can't complain much about that circuit. It only needs more extention in HF, more soundstage and slightly improved tonal balance. When this is achieved, it will be a very good DAC. I compared it to modified high end one box player (which supposed to be one of the best currently) and this little DAC was still a match. Looking at simlicity and investment, I'd say, it's not bad😉
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