HiFiNutNut said:
Right, as said above, when you mod like this:
Coupling caps from the DAC to the opamps
C375 parallel with C377/C376 parallel with C378
replaced with cupperfoil paper-in-oil caps. They are quite large and are suspended in foam to avoid that they touch any components on the PCB.
The M302A crystal and the ceramics C328-339 removed and a Tentlabs XO2 clock is applied with a dedicated PSU (transformer, rectifier, smoothing elcap in parallel with a small 100nF MKT)
the sound gets more fine grained, the soundstage becomes wider, deeper and taller, a major improvement!
i opened my 542 cd player today, i see that some caps are marked samcon, licon etc...dont know exactly, the power transformer is chinese made, the power regulators are hot to touch. one jumper has been cut "J119" dont know why they do that. any such findings? mine was made in china marked version c. is it ok that this player is made in china???
Klitgt,
Yes I did the same replacement on the caps after the DAC. I used an ICW SA Clarity cap (rather inexpensive but much better than the Solen MKP as I have done A/B tests on these two brands, the cheapest source I found on the net is www.ledeaudio.com) 2.2uF 630V that can just fit. The value of this cap is really unimportant as long as you recalculate the resistor shunt to ground after the cap using the formula R = 1 / (2 x PI x F x C). I made the -3dB pont to be fairly low using a 68k resistor. Of course, larger resistors will ensure that the low frequencies are good but they will introduce more noise which is accumulative in the audio chain. I would say a 1u to 2.2uF with 100k to 47k would be really good enough. I would say this is the most significant upgrade one can make to the player.
Did you do both mods at the same time or the clock upgrade later on? How much difference the clock makes?
Ricman,
I think these NAD542s are made in China. Mine has the OPA2134, Nichicon MUSE as the coupling cap, Nichicon Fine Gold throughout the analogue section, and Elna general type in the PSU and other more critical sections, and misc brands for other areas such as display, etc. It is not too bad. I left the OPA2134 and some Nichicon Fine Gold there.
Anyone has the service manual for the NADT550 DVD Player? (I have one I want to mod) and a NAD receiver? (I want to buy one and mod it)
Contexchen,
All NADs in recent years are made in China and I heard that there are a lot of quality issues. My NAD541i now has intermittant reading problems. As you know that there are a number of bugs in the NAD541i so very soon after its release NAD made the NAD542 release. So forget about the NAD541i and buy a NAD542. Fortunately, the NAD542 has been there for a while now without upgrade which means it should be a more reliable product. I certainly hope so. As mentioned earlier, one can't replace the DC blocking cap (or coupling cap) after the DAC before the opamp easily on the NAD541i unless you want to adopt the NAD542 circuit by mounting a separate board. That is too much for me. I have not done that and my modded NAD542 is substantially better than the modded NAD541i.
Regards,
Bill
Yes I did the same replacement on the caps after the DAC. I used an ICW SA Clarity cap (rather inexpensive but much better than the Solen MKP as I have done A/B tests on these two brands, the cheapest source I found on the net is www.ledeaudio.com) 2.2uF 630V that can just fit. The value of this cap is really unimportant as long as you recalculate the resistor shunt to ground after the cap using the formula R = 1 / (2 x PI x F x C). I made the -3dB pont to be fairly low using a 68k resistor. Of course, larger resistors will ensure that the low frequencies are good but they will introduce more noise which is accumulative in the audio chain. I would say a 1u to 2.2uF with 100k to 47k would be really good enough. I would say this is the most significant upgrade one can make to the player.
Did you do both mods at the same time or the clock upgrade later on? How much difference the clock makes?
Ricman,
I think these NAD542s are made in China. Mine has the OPA2134, Nichicon MUSE as the coupling cap, Nichicon Fine Gold throughout the analogue section, and Elna general type in the PSU and other more critical sections, and misc brands for other areas such as display, etc. It is not too bad. I left the OPA2134 and some Nichicon Fine Gold there.
Anyone has the service manual for the NADT550 DVD Player? (I have one I want to mod) and a NAD receiver? (I want to buy one and mod it)
Contexchen,
All NADs in recent years are made in China and I heard that there are a lot of quality issues. My NAD541i now has intermittant reading problems. As you know that there are a number of bugs in the NAD541i so very soon after its release NAD made the NAD542 release. So forget about the NAD541i and buy a NAD542. Fortunately, the NAD542 has been there for a while now without upgrade which means it should be a more reliable product. I certainly hope so. As mentioned earlier, one can't replace the DC blocking cap (or coupling cap) after the DAC before the opamp easily on the NAD541i unless you want to adopt the NAD542 circuit by mounting a separate board. That is too much for me. I have not done that and my modded NAD542 is substantially better than the modded NAD541i.
Regards,
Bill
Bill: Did you do both mods at the same time or the clock upgrade later on? How much difference the clock makes?
I did both at the same time and do not know which is most important. However, the total improvement was so large, that I can not imagine that it is a credit to the cap alone and the clock as a minor contributor.
I did both at the same time and do not know which is most important. However, the total improvement was so large, that I can not imagine that it is a credit to the cap alone and the clock as a minor contributor.
My mods
Hi!
I just wanted to report my mods, as I got a nice pdf service manual from Mosez the other day.
I've done these things to my C541i (unfortunately as one batch):
- Changed some "Fine Gold" caps to OS-CON SA's (pwr supply bypass for output opamps).
- Changed clock to TentLabs XO w/ pwr supply as per tentlabs example on website.
- Removed muting transistors.
- Removed OPA 2604's and put sockets in. Put OPA2132P's in sockets.
How does it sound? Well, it's more fine-grained and detailed, but it actually lacks some punch compared to un-modified. I'd really like to remove these ugly 'lytics in the signal chain, but after looking at the schematics I think about making a completely new output stage. BTW, does the C541i invert the signal, or am I not getting it?
- Pelle
PS. The datasheet for these "Fine Gold" caps didn't contain much technical data, but rather lots-o-crap-phrases, snake oil warning!
Hi!
I just wanted to report my mods, as I got a nice pdf service manual from Mosez the other day.
I've done these things to my C541i (unfortunately as one batch):
- Changed some "Fine Gold" caps to OS-CON SA's (pwr supply bypass for output opamps).
- Changed clock to TentLabs XO w/ pwr supply as per tentlabs example on website.
- Removed muting transistors.
- Removed OPA 2604's and put sockets in. Put OPA2132P's in sockets.
How does it sound? Well, it's more fine-grained and detailed, but it actually lacks some punch compared to un-modified. I'd really like to remove these ugly 'lytics in the signal chain, but after looking at the schematics I think about making a completely new output stage. BTW, does the C541i invert the signal, or am I not getting it?
- Pelle
PS. The datasheet for these "Fine Gold" caps didn't contain much technical data, but rather lots-o-crap-phrases, snake oil warning!
Re: My mods
You should probably not change the "fine gold" caps, they seem OK.
The clock should be the XO2 with a separate PSU (just a small transformer 9V, rectifier, smoothing 470uF elcap parallel with 100nF MKT. Guido recommends it as a step up from the XO DIY version.
Try the OPA2134, it is in the C542, or the SMD version of OPA627, 2 on an adapter from Browndog
http://cimarrontechnology.com/index.asp?PageAction=VIEWCATS&Category=5
With the OPA2134 or OPA627 it is possible to remove the output capacitors C368/369 and C379/382 and apply jumpers. The OPA2134/627 have practically no DC offset.
You must keep the C375/376 and C377/378 blocking DC from the V-out DAC, but replace them with polypropylenes or the like audio caps.
If you can afford the OPA627 you do not need a new output stage. The OPA627 is very fast, dry and deep in the bass register, while maintaining the good qualities, if not doing better, in the mids and treble than the OPA2132/2134.
eplpwr said:
You should probably not change the "fine gold" caps, they seem OK.
The clock should be the XO2 with a separate PSU (just a small transformer 9V, rectifier, smoothing 470uF elcap parallel with 100nF MKT. Guido recommends it as a step up from the XO DIY version.
Try the OPA2134, it is in the C542, or the SMD version of OPA627, 2 on an adapter from Browndog
http://cimarrontechnology.com/index.asp?PageAction=VIEWCATS&Category=5
With the OPA2134 or OPA627 it is possible to remove the output capacitors C368/369 and C379/382 and apply jumpers. The OPA2134/627 have practically no DC offset.
You must keep the C375/376 and C377/378 blocking DC from the V-out DAC, but replace them with polypropylenes or the like audio caps.
If you can afford the OPA627 you do not need a new output stage. The OPA627 is very fast, dry and deep in the bass register, while maintaining the good qualities, if not doing better, in the mids and treble than the OPA2132/2134.
My mods, clarification
Hi klitgt!
Well, really, the OPA2132P's that I'm using is sort of the high-spec'd version of the OPA2134. The 2132's (esp the 'P' version) got somewhat lower offset and better CMRR.
I actually have a separate trafo for the Clock, with separate rectifier and smoothing caps. The only difference between my "PS" and the schematic on the TentLabs site, is that I'm using an '317T instead of a '7808 as the first regulator.
Regarding the OPA627, I will try these soon as I have both SMD and DIL versions available. To get going as fast as possible, I'll make my own adapters this evening. I'm currently using OPA627's in my preamp, and so far I haven't found anything that can match these devices when it comes to sound quality.
I will remove the output caps soon, and also try to replace the DC-blocking caps on the DAC's output with large'ish film caps. The biggest problem I've had so far with the C541i is to remove the cables between the CD transport and the main PCB gracefully, these small connectors (on the transport side) are really a tight fit.
Regarding the "Fine Gold" caps, I'm just not impressed with datasheets that claim "Rich sound in the bass register and clearer high end" but leave out such important information as ESR. Well, thats my opinion and since I know there are other opinions I would not like to start an endless discussion on that topic.
Regards,
Hi klitgt!
Well, really, the OPA2132P's that I'm using is sort of the high-spec'd version of the OPA2134. The 2132's (esp the 'P' version) got somewhat lower offset and better CMRR.
I actually have a separate trafo for the Clock, with separate rectifier and smoothing caps. The only difference between my "PS" and the schematic on the TentLabs site, is that I'm using an '317T instead of a '7808 as the first regulator.
Regarding the OPA627, I will try these soon as I have both SMD and DIL versions available. To get going as fast as possible, I'll make my own adapters this evening. I'm currently using OPA627's in my preamp, and so far I haven't found anything that can match these devices when it comes to sound quality.
I will remove the output caps soon, and also try to replace the DC-blocking caps on the DAC's output with large'ish film caps. The biggest problem I've had so far with the C541i is to remove the cables between the CD transport and the main PCB gracefully, these small connectors (on the transport side) are really a tight fit.
Regarding the "Fine Gold" caps, I'm just not impressed with datasheets that claim "Rich sound in the bass register and clearer high end" but leave out such important information as ESR. Well, thats my opinion and since I know there are other opinions I would not like to start an endless discussion on that topic.
Regards,
New output stage
adinica,
I've compared the C542 output stage with the original in my C541i, and there seem the've made several improvements in design and component choices, like the OPA2134 instead of OPA2604, better caps et al.
I also note that the output of the C542 is "true to the original", in that they have two gain stages with positive gain. The C541i has an inverting stage first, followed by a unity gain stage: the result is an inverted output, which I think is bad engineering.
Since I didn't like the output stage of the C541i I've designed a new output stage (Gain=+4.5), using one OPA627 per channel. I am quite happy with the sound of it.
Best Regards,
adinica,
I've compared the C542 output stage with the original in my C541i, and there seem the've made several improvements in design and component choices, like the OPA2134 instead of OPA2604, better caps et al.
I also note that the output of the C542 is "true to the original", in that they have two gain stages with positive gain. The C541i has an inverting stage first, followed by a unity gain stage: the result is an inverted output, which I think is bad engineering.
Since I didn't like the output stage of the C541i I've designed a new output stage (Gain=+4.5), using one OPA627 per channel. I am quite happy with the sound of it.
Best Regards,
Hi every one
Again, a question that previously asked by some one in this thread:
NAD is very bad at its mechanism. My C541 CD tray and mechanism is degraded now, and my CDP also has tracking problem. If any of you have experience with this, please share how did you solve the problem?
Do you think it's a good idea to change to a new mechanism? Is it too complicated to do so?
Many thanks and hear from you.
Again, a question that previously asked by some one in this thread:
NAD is very bad at its mechanism. My C541 CD tray and mechanism is degraded now, and my CDP also has tracking problem. If any of you have experience with this, please share how did you solve the problem?
Do you think it's a good idea to change to a new mechanism? Is it too complicated to do so?
Many thanks and hear from you.
Guido Tent said:
Hi Guido Tent
what you said is a very popular practice among audioplayer in my city. I have checked my CDP and it doesn't have problem with the lens. The problem comes from the mechanism. I have lubricated the rail on which the lens moves, but seems not work. I'm thinking of tweaking the NAD by having a new mechanism, but many said, it costs and complicated.
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.
C541i mods
Thanks!
I will try to be precise since my English is not very good
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
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
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