ccontreras said:Thanks!
I will try to be precise since my English is not very good
An externally hosted image should be here but it was not working when we last tested it.
1.- points white: caps blackgate FK 2200uf / 35v (before 1000uF 25v)
2.- point orange: cap Blackgate 1000uf / 16v (before 470uF 16v)
3.- points yellow: Opams AD826 (before OPA2604)
4.- points blue: caps blackgate 47uf / 25v (before 470uF 25v)
5.- points black: Auricaps 4.7uf / 200v (before 100uF 16v)
and removed muting transistors
I need suggestions and advice... thanks
Can you tell us how the sound changed (improved?) compared to pre-mod?
Anyone has any suggestions or advice for ccontreras?
The sound would definitely be better if you use better parts.
One very critical part is the DC blocking capacitor. I have modified both the 541i and 542. When I got to the 541i I got a bit stuck. I could not remove the large value output cap unless I changed the circuit around the opamp to that of the 542 for reasons somebody mentioned earlier. So both my 541i and 542 contained the same mods except the output cap, and I have to say the 542 sounds a lot better.
I have concluded that that 541i is not the best candidate for mod while the 542 is.
In the next week or so I will continue to mod my 542. I will replace the opa2134 with the opa627 and also improve the PSU for the analogue output.
If that gives me good improvement, I guess I will install 2 tent clocks. They are expensive so I will leave them to the last, and only if I think they are worthwhile for the NAD. According to NAD, they emphasized that you have achieved very low jitter. If the statement is true then it may not be worthwhile to upgrade the clocks. There are two so I would need two Tent clocks and build a dedicated PSU.
Regards,
Bill
One very critical part is the DC blocking capacitor. I have modified both the 541i and 542. When I got to the 541i I got a bit stuck. I could not remove the large value output cap unless I changed the circuit around the opamp to that of the 542 for reasons somebody mentioned earlier. So both my 541i and 542 contained the same mods except the output cap, and I have to say the 542 sounds a lot better.
I have concluded that that 541i is not the best candidate for mod while the 542 is.
In the next week or so I will continue to mod my 542. I will replace the opa2134 with the opa627 and also improve the PSU for the analogue output.
If that gives me good improvement, I guess I will install 2 tent clocks. They are expensive so I will leave them to the last, and only if I think they are worthwhile for the NAD. According to NAD, they emphasized that you have achieved very low jitter. If the statement is true then it may not be worthwhile to upgrade the clocks. There are two so I would need two Tent clocks and build a dedicated PSU.
Regards,
Bill
HiFiNutNut said:
Hi
Last week I modded 1 NAD C542, for a demo, comparing it with a non modded 542
I changed all diodes to Schottky Barier, removed the output muting transistors, changed the clock and fed the analog supply of the DAC chip with a shunt regulator.
The result is stunning. One thing that can be improved is the layout, which is a true drama. But this requires skills and experience, and time....
best
Do I need 2 XO II boards or just one for the NAD542? The XO board seems to have two outputs?
Where can I get a shunt regulator?
My next mod is going to be very tricky.
Initially for experiment I soldered 2 x 2,200uF Zubycon ZL after the regulator for the analogue output. That sounds very good. I have compared them to using 4,700uF FC or without the additional caps and much preferred having the 2,200uF ZL. It has low impedance and I supposed low ESR as well due to its size. Taking them out the music becomes very dry.
However, I am sure it is causing some resonances that I don't have a scope to measure but I can hear distortions occassionally. We all know this is due to the series inductance of the LM317 regulator and the capactance of the capacitors forming a resonce circuit, and with super low ESR caps the resistance is not high enough to damp it.
So what should I do? If I can get a good shunt regulator I would. But if you have a look at the Soundlabs group's regulator you know the price of that shunt regulator is 80% of the price of the NAD542! Insane, isn't it?
What is in my mind is to add a 1 ohm resistor in series at the output of the LM317, and use 1,000uF or 1,500uF ZL after the resistor for each chip for each rail. What do you think? Interestingly, NAD542 has those resistors marked and printed in the PCB, but they are shunted. That is very convenient. I worry by doing it this way, the impedance of the PSU is lifted, transient response may be reduced, and the sound of the ZL will be more influential (i.e. distortions). Would it be a problem? This is for the OPA627.
Do you have experience on this? Any good regulator you can recommend?
Regards,
Bill
Where can I get a shunt regulator?
My next mod is going to be very tricky.
Initially for experiment I soldered 2 x 2,200uF Zubycon ZL after the regulator for the analogue output. That sounds very good. I have compared them to using 4,700uF FC or without the additional caps and much preferred having the 2,200uF ZL. It has low impedance and I supposed low ESR as well due to its size. Taking them out the music becomes very dry.
However, I am sure it is causing some resonances that I don't have a scope to measure but I can hear distortions occassionally. We all know this is due to the series inductance of the LM317 regulator and the capactance of the capacitors forming a resonce circuit, and with super low ESR caps the resistance is not high enough to damp it.
So what should I do? If I can get a good shunt regulator I would. But if you have a look at the Soundlabs group's regulator you know the price of that shunt regulator is 80% of the price of the NAD542! Insane, isn't it?
What is in my mind is to add a 1 ohm resistor in series at the output of the LM317, and use 1,000uF or 1,500uF ZL after the resistor for each chip for each rail. What do you think? Interestingly, NAD542 has those resistors marked and printed in the PCB, but they are shunted. That is very convenient. I worry by doing it this way, the impedance of the PSU is lifted, transient response may be reduced, and the sound of the ZL will be more influential (i.e. distortions). Would it be a problem? This is for the OPA627.
Do you have experience on this? Any good regulator you can recommend?
Regards,
Bill
I have both the 541i and the 542 and both contain the same mods except as said I did not replace the output caps (which is very important) of the 541i. Of course the 541i uses 2604 while the 542 uses 2134. I can say the 542 is much better. Circuit difference is not that big so I suspect the difference is mainly due to the output caps (70%?) and the opamps (30%?) but I really don't know which. Simon is right on this.
I guess I will find out the answer next week when I replace the 2134 with 627.
I guess I will find out the answer next week when I replace the 2134 with 627.
I have now compared my NAD542 to many other players. All comparisons were made in my system. I now think it is neck to neck to the CEC top loading player, the Aragon DAC 2A2 on redbook CDs, the Chord DAC64 (only when using the NAD as the transport) (AUD$6,500), The Burmester Rondo (AUD$4,000-$8,000).
The mods cost me only $75 so far, but 3 months in studies, 3 weeks in design, and 7 hours labour in solding and desoldering, drilling, etc.
Details and resolution may not be as good as many of those players. However, the modified NAD542 is more transparent, dynamic, open, at the same time maintains a soft, sweet, analogue, musical sound. Each player is different but overall I think the NAD is just as good, better in some areas and worse in others.
It was hard to say how does it compare to the Audionote DAC Zero. I did compare it but they are completely different beasts.
It is a lot more musical than the Marantz SA11 I bought (AUD$4,200rrp).
But it lost to the Meridian G08 (AUD$6,800). I guess the Meridian G08 is the best CD player among all of the above. Unfortunately, it is beyond my budget. It was funny that the G08 sounds very good on my (presumed) very high-end all-diy system, but a bit cold or digital on my friends' system.
I have just bought the Marantz SA11 service manual and am currently working on it. It is such a massive (15kg), beautiful machine with pretty much premium components constructed in a very high-end way. Very impressive. However, I don't know why it does not sound very musical. It definitely gives you a Hi-End sound but not much music. For individual musical instruments, it blows the NAD542 away with its accuracy, but when putting things together, the NAD gives you music, makes you dance and cry, but the Marantz seems to be cold, hard and lack of emotions. Oh, how can I make the Marantz musical? Don't get me wrong. The NAD does not sound like an Audionote. It does not really sound warm (I mean with loads of 2nd order harmonic distortions). But it does not sound hard or cold neither. It has a natural sound. Hearing the gradual decay of the sound in the ambience it just beats many other players out there. I mean accurate sound. I mainly only listen to classical and jazz.
I will improve the PSU further on the NAD542 when I upgrade it using the OPA627. Then I may consider clock upgrade (6 times more expensive than all the mods I have done combined) but would it give 10% improvements comparing to the other mods I have done? I don't know. I may find it out. Of course, when a player gets this good, spending another a few hundred dollars to get 5% improvement may be worthwhile. It depends on how I go with my Marantz.
The most exciting thing to me now is to mod the Marantz SA11. When looking at the Marantz SA11 schematic it looks pretty good already and I simply don't know how much I can do on it. I can improve the PSU (it is using the Elna Cerefine throughout) and I can replace the output caps (100uF Elna Silimic) with a MKP. What else? unless I want to replace the HDAMs. But are the HDAMs supposed to sound better than the opamps? Of course there are no opamps to upgrade.
Regards,
Bill
The mods cost me only $75 so far, but 3 months in studies, 3 weeks in design, and 7 hours labour in solding and desoldering, drilling, etc.
Details and resolution may not be as good as many of those players. However, the modified NAD542 is more transparent, dynamic, open, at the same time maintains a soft, sweet, analogue, musical sound. Each player is different but overall I think the NAD is just as good, better in some areas and worse in others.
It was hard to say how does it compare to the Audionote DAC Zero. I did compare it but they are completely different beasts.
It is a lot more musical than the Marantz SA11 I bought (AUD$4,200rrp).
But it lost to the Meridian G08 (AUD$6,800). I guess the Meridian G08 is the best CD player among all of the above. Unfortunately, it is beyond my budget. It was funny that the G08 sounds very good on my (presumed) very high-end all-diy system, but a bit cold or digital on my friends' system.
I have just bought the Marantz SA11 service manual and am currently working on it. It is such a massive (15kg), beautiful machine with pretty much premium components constructed in a very high-end way. Very impressive. However, I don't know why it does not sound very musical. It definitely gives you a Hi-End sound but not much music. For individual musical instruments, it blows the NAD542 away with its accuracy, but when putting things together, the NAD gives you music, makes you dance and cry, but the Marantz seems to be cold, hard and lack of emotions. Oh, how can I make the Marantz musical? Don't get me wrong. The NAD does not sound like an Audionote. It does not really sound warm (I mean with loads of 2nd order harmonic distortions). But it does not sound hard or cold neither. It has a natural sound. Hearing the gradual decay of the sound in the ambience it just beats many other players out there. I mean accurate sound. I mainly only listen to classical and jazz.
I will improve the PSU further on the NAD542 when I upgrade it using the OPA627. Then I may consider clock upgrade (6 times more expensive than all the mods I have done combined) but would it give 10% improvements comparing to the other mods I have done? I don't know. I may find it out. Of course, when a player gets this good, spending another a few hundred dollars to get 5% improvement may be worthwhile. It depends on how I go with my Marantz.
The most exciting thing to me now is to mod the Marantz SA11. When looking at the Marantz SA11 schematic it looks pretty good already and I simply don't know how much I can do on it. I can improve the PSU (it is using the Elna Cerefine throughout) and I can replace the output caps (100uF Elna Silimic) with a MKP. What else? unless I want to replace the HDAMs. But are the HDAMs supposed to sound better than the opamps? Of course there are no opamps to upgrade.
Regards,
Bill
I have 542 also. Can someone please send me the service manual? My e-mali is:
bukoljubac@yahoo.co.uk
I haven't done any mods yet, but I'm gathering parts for clock and analog section regulation. How's the sound with OPA627?
bukoljubac@yahoo.co.uk
I haven't done any mods yet, but I'm gathering parts for clock and analog section regulation. How's the sound with OPA627?
Here is my new report.
Over the weekend I did another upgrade to my NAD542.
To reduce the risk of getting possible resonance I added a 1 ohm resistor in series with the LM317 / LM337 and installed some large value low impedance capacitors. It sounded very different but eventually I decided to ditch it. Definitely no resistors after the regulators. The lower the impedance the better the sound. I will let it resonate if it does.
The new capacitors have an impedance of only 0.012R at 100kHz. I thought that was pretty low and took out the 0.01uF polystyrene bypass caps. It sounded bad. The were back on.
I never thought that the capacitors before the regulators 317/337 are important. The NAD has the 1000uF Nichicon Fine Gold that is supposed to be a good capacitor. I thought using lower value capacitors would reduce the conduction angle during the charge cycle. That might be right. But as far as sonic is concerned, I was wrong. Putting on the Panasonic 4,700uF made a huge improvement.
Finally, I replaced the OPA2134 with the OPA627. By the way, I bought 2 pairs of "dual" OPA627 mounted on browndogs from eBay (seller: ca2832) and another pairs of single AD825 on browndogs. Chris is the guy selling them. They are the cheapest I found. Most important of all, they are genuine products and Chris shipped them in no time. I am very happy with the purchase and can highly recommend Chris.
When the OPA627 was plugged in, I found basically no difference at the time. Perhaps I was still getting used to the much improved sound from the big Panasonic FC before the regulators. The next day, I unplugged the OPA627 and plugged in the OPA2134, I heard the difference immediately. The sound was less clear. I then put the OPA627 back on. It sounded clearer.
Basically, both have the same sound character and presentation. Both are nice. The OPA2134 is more coloured making the tone slightly warmer. The OPA627 is more transparent as if it does not have its own sound, and more detailed. They are more similar than different, unlike the AD825. The OPA627 is overall better than the OPA2134.
I have learnt a lesson here. It all depends. If you look at the datasheet, you can find that the OPA627 has much better PSRR than the OPA2134. So when used in a noisier PSU, I presume, the OPA627 will outperform the OPA2134 by a large margin. If used in a very quiet PSU, the OPA627 only has slightly higher bandwidth and higher slew rate so it would give you better details but not a "night and day" difference. If you hear people saying the OPA627 being substantially better than the OPA2134. That may probably be right. The other way may also be true - if you hear people saying the OPA627 being no difference to the OPA2134. It all depends on many other factors.
I would think replacing the PSU capacitors makes bigger difference than replacing the opamps. On my system, all the major caps are replaced. So the OPA627 stay. They are definitely better.
But if you have not replaced anything yet, spending $30 on capacitors may give you 80% sonic improvement, spending $100 on the opamps may give you 20% improvement.
I also helped my friend with his Aragon DAC. It had NE5534s in it. We first replaced it with OPA2134. The sound was a lot better. Then we replaced the OPA2134 with AD825. The difference was huge. It immediately gave a high-end feeling. Much better resolution, high frequency details, etc. But after 10 minutes, we both agreed that the sound was a bit cold comparing to the OPA2134, and vocals might not be as sweet as the OPA2134. My friend then took it back. After one week, he told me the AD825 is definitely better than the OPA2134. Either he is now used to the new sound, or in his warm system the AD825 simply sounds a lot better. He believes that the AD825 is not lesser than the OPA2134 in the mid range. It is because the high and low frequency extremes now sound better it makes the midrange appears to be less sweet.
In any case, my NAD542 now sounds really nice with the latest round of upgrade, so nice that I really have no intension to do anything else on it. I have lost the interests in installing new clocks on it.
Regards,
Bill
Over the weekend I did another upgrade to my NAD542.
To reduce the risk of getting possible resonance I added a 1 ohm resistor in series with the LM317 / LM337 and installed some large value low impedance capacitors. It sounded very different but eventually I decided to ditch it. Definitely no resistors after the regulators. The lower the impedance the better the sound. I will let it resonate if it does.
The new capacitors have an impedance of only 0.012R at 100kHz. I thought that was pretty low and took out the 0.01uF polystyrene bypass caps. It sounded bad. The were back on.
I never thought that the capacitors before the regulators 317/337 are important. The NAD has the 1000uF Nichicon Fine Gold that is supposed to be a good capacitor. I thought using lower value capacitors would reduce the conduction angle during the charge cycle. That might be right. But as far as sonic is concerned, I was wrong. Putting on the Panasonic 4,700uF made a huge improvement.
Finally, I replaced the OPA2134 with the OPA627. By the way, I bought 2 pairs of "dual" OPA627 mounted on browndogs from eBay (seller: ca2832) and another pairs of single AD825 on browndogs. Chris is the guy selling them. They are the cheapest I found. Most important of all, they are genuine products and Chris shipped them in no time. I am very happy with the purchase and can highly recommend Chris.
When the OPA627 was plugged in, I found basically no difference at the time. Perhaps I was still getting used to the much improved sound from the big Panasonic FC before the regulators. The next day, I unplugged the OPA627 and plugged in the OPA2134, I heard the difference immediately. The sound was less clear. I then put the OPA627 back on. It sounded clearer.
Basically, both have the same sound character and presentation. Both are nice. The OPA2134 is more coloured making the tone slightly warmer. The OPA627 is more transparent as if it does not have its own sound, and more detailed. They are more similar than different, unlike the AD825. The OPA627 is overall better than the OPA2134.
I have learnt a lesson here. It all depends. If you look at the datasheet, you can find that the OPA627 has much better PSRR than the OPA2134. So when used in a noisier PSU, I presume, the OPA627 will outperform the OPA2134 by a large margin. If used in a very quiet PSU, the OPA627 only has slightly higher bandwidth and higher slew rate so it would give you better details but not a "night and day" difference. If you hear people saying the OPA627 being substantially better than the OPA2134. That may probably be right. The other way may also be true - if you hear people saying the OPA627 being no difference to the OPA2134. It all depends on many other factors.
I would think replacing the PSU capacitors makes bigger difference than replacing the opamps. On my system, all the major caps are replaced. So the OPA627 stay. They are definitely better.
But if you have not replaced anything yet, spending $30 on capacitors may give you 80% sonic improvement, spending $100 on the opamps may give you 20% improvement.
I also helped my friend with his Aragon DAC. It had NE5534s in it. We first replaced it with OPA2134. The sound was a lot better. Then we replaced the OPA2134 with AD825. The difference was huge. It immediately gave a high-end feeling. Much better resolution, high frequency details, etc. But after 10 minutes, we both agreed that the sound was a bit cold comparing to the OPA2134, and vocals might not be as sweet as the OPA2134. My friend then took it back. After one week, he told me the AD825 is definitely better than the OPA2134. Either he is now used to the new sound, or in his warm system the AD825 simply sounds a lot better. He believes that the AD825 is not lesser than the OPA2134 in the mid range. It is because the high and low frequency extremes now sound better it makes the midrange appears to be less sweet.
In any case, my NAD542 now sounds really nice with the latest round of upgrade, so nice that I really have no intension to do anything else on it. I have lost the interests in installing new clocks on it.
Regards,
Bill
Simon,
Well, when the NAD542 was released, in NAD's literature it said that they paid a lot of attention to reducing jitters and they achieved it. Of course that is NAD's statement.
My NAD now sounds very good - dynamic, open, transparent, musical and reasonably detailed. It is not as accurate or as high-end as the Marantz SA11 I have, but it does give the same level of musical enjoyment. As said, I have compared it to many players and it only lost to the Meridian G08, which is the only player I am really happy with.
I do believe that replacing the clocks would help. However, this player costs only AUD$680. My mod (including 4 x OPA627) cost just under AUD$200. Its current level of performance would not be lesser than players up to $5,000. I should be happy. The problem is that for the NAD542 you need to install two clocks according to the TentLab Australian agent GeorgeHiFi. The DIY costs including buying two Tent clocks and buying components to build a dedicated PSU for the two XO clocks would be above AUD$300. Further more, I must find the space within the enclosure to fit in and mount 3 separate boards. If I have not had the Marantz SA11, I would possibly go for it. But my NAD is only my second player so I will leave it. I did seriously consider installing new clocks but now finally decided not to proceed.
I will start modding my Marantz SA11 tonight. You guys wish me good luck?
Regards,
Bill
Well, when the NAD542 was released, in NAD's literature it said that they paid a lot of attention to reducing jitters and they achieved it. Of course that is NAD's statement.
My NAD now sounds very good - dynamic, open, transparent, musical and reasonably detailed. It is not as accurate or as high-end as the Marantz SA11 I have, but it does give the same level of musical enjoyment. As said, I have compared it to many players and it only lost to the Meridian G08, which is the only player I am really happy with.
I do believe that replacing the clocks would help. However, this player costs only AUD$680. My mod (including 4 x OPA627) cost just under AUD$200. Its current level of performance would not be lesser than players up to $5,000. I should be happy. The problem is that for the NAD542 you need to install two clocks according to the TentLab Australian agent GeorgeHiFi. The DIY costs including buying two Tent clocks and buying components to build a dedicated PSU for the two XO clocks would be above AUD$300. Further more, I must find the space within the enclosure to fit in and mount 3 separate boards. If I have not had the Marantz SA11, I would possibly go for it. But my NAD is only my second player so I will leave it. I did seriously consider installing new clocks but now finally decided not to proceed.
I will start modding my Marantz SA11 tonight. You guys wish me good luck?
Regards,
Bill
My Marantz CD63 also needs two clocks, but in reality they can be fed from the same source, with the use of a divider cicruit. Reclocking the DAC made a huge improvement (timing, detail, imaging etc.), then feeding the servo a new clock signal made another huge improvement (finally really detailed and a more lifelike top end).
I wonder if this would be the case in the Nad.
Good luck with your SA11
I wonder if this would be the case in the Nad.
Good luck with your SA11
Hi Bill,
CD67 just needs the one clock. If you spend time separating supplies for the 5v parts and you reclock you will be stunned. Also change the op-amps to LM4562. You may also like the sound with 'HDAM' bypassed. Just look at all the people doing it on the mammoth thread elsewhere here.
Sorry, this is off-topic.
Simon
CD67 just needs the one clock. If you spend time separating supplies for the 5v parts and you reclock you will be stunned. Also change the op-amps to LM4562. You may also like the sound with 'HDAM' bypassed. Just look at all the people doing it on the mammoth thread elsewhere here.
Sorry, this is off-topic.
Simon
HiFiNutNut said:
If you want to install a better clock you need to replace only one (labeled M302 on the board) in your NAD542 since I have done the same in mine too.
NAD542 is a bit tricky but it can be upgraded to a significant degree at reasonable cost.
Many tweaks that are generally known work here too.
Regards,
Baka
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