NAD S500, AudioNote Dac1.2 upgrades

[Bryan]

Hey Guys,

I'm currently using a NAD S500 to feed an AudioNote DacKit 1.2.
I would like to upgrade the setup, and I have some basic questions.

First, where to start? Mod the dac, mod the NAD, sell something and replace???

I've searched around and have not found much information pertaining to modding the NAD. There are some options for alterations to the Dac, which could be interesting (PS, I/V transformer...) along with many others I'm sure. Maybe I would be better with a dedicated transport???

My goals here are not to spend tons of money, as I'm kinda broke and the holidays are around the corner.

Any suggestions are appreciated .

Thanks,

Bryan

 

[Elso Kwak]

Hey Guys,

I'm currently using a NAD S500 to feed an AudioNote DacKit 1.2.
I would like to upgrade the setup, and I have some basic questions.

First, where to start? Mod the dac, mod the NAD, sell something and replace???

I've searched around and have not found much information pertaining to modding the NAD. There are some options for alterations to the Dac, which could be interesting (PS, I/V transformer...) along with many others I'm sure. Maybe I would be better with a dedicated transport???

My goals here are not to spend tons of money, as I'm kinda broke and the holidays are around the corner.

Any suggestions are appreciated .

Thanks,

Bryan

Hi Bryam,
Start with the clock in the player. Then do something about the SPDIF interface and the CS8412. For the DAC see also:
http://db.audioasylum.com/cgi/m.pl?forum=digital&n=71918&highlight=elso+audionote&r=&session=
For the clock see this enlightening discussion:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=22269&perpage=15&pagenumber=1

 

[Prometheus]

I've borrowed the NAD S500 for a home trial before. Like almost all CD players with the VAM 1202/12, it's somewhat lean sounding. That's fine if you like that though.

Anyway, the VAM 1202/12 is not a very good transport. You can try selling that S500 and buying a used Marantz or Philips player with CDM 1/1mkII/2/4/9. That's an instant upgrade with money to spare.

 

[carlosfm]

I've borrowed the NAD S500 for a home trial before. Like almost all CD players with the VAM 1202/12, it's somewhat lean sounding. That's fine if you like that though.

Anyway, the VAM 1202/12 is not a very good transport. You can try selling that S500 and buying a used Marantz or Philips player with CDM 1/1mkII/2/4/9. That's an instant upgrade with money to spare.

"lean sounding" because of the transport?

You'd better have checked those op-amps.

 

[Drew]

I had a chance to play with an S500 about 1 1/2yr ago. Nice Player. Sounds a little lean heh? Sound deading the transport and chasis, do some work on the power supply side of the unit, upgrade the recitifer and power supply caps. And upgrading the op-amp would improve the unit lots. Try some different power cords too.

 

[Bryan]

Ok... Lets focus on the NAD S500

Thanks for the initial responses.

I'd like to tweak the player before selling it off, and trying something entirely new. That being said, it seems the simple steps would be to add dampening to the transport/chassis, tweak power cords (currently DIY), beef up the PS, and maybe change the clock and/or opamps.

OK, this is where my digital ignorance becomes apparent. The PS and resonance issues I can handle. What I would like to know more about is changing the clock or opamps.

Again, forgive my ignorance, but what EXACTLY does the clock and the opamp do? I've read about better clocks providing less jitter, but how does this happen? I've read about opamps being upgraded or removed for better sonics, so how do these devices work? Are these relatively easy tweaks, or do they require a significant amount of expertise? I've built a few amp, some from scratch, and the DacKit, so I know my way around the solder gun, but I have never really messed around with "digital stuff"


Also, keep in mind I'm only using the NAD as a transport, so I'm not currently interested in changing the DAC section, only the transport functions.

I'll probably sell off the NAD to my brother down the line, so I would like to keep it functional as a stand alone player during any modifications...



Any more advice from the experts? Hopefully with your help I can get a plan together, and start hearing the benefits! Of course, it would help if I bought one of those damn star-shaped pseudo-hex adaptors so I can open up the hood



Thanks Guys,

Bryan

 

[Guido Tent]

Re: Ok... Lets focus on the NAD S500

Thanks for the initial responses.

Again, forgive my ignorance, but what EXACTLY does the clock and the opamp do? I've read about better clocks providing less jitter, but how does this happen?

Also, keep in mind I'm only using the NAD as a transport, so I'm not currently interested in changing the DAC section, only the transport functions.

I'll probably sell off the NAD to my brother down the line, so I would like to keep it functional as a stand alone player during any modifications...



Any more advice from the experts? Hopefully with your help I can get a plan together, and start hearing the benefits! Of course, it would help if I bought one of those damn star-shaped pseudo-hex adaptors so I can open up the hood



Thanks Guys,

Bryan

Hello Bryan,

About jitter:

When describing the amplitude of a signal, we take a sample every once and a while. When the amplitude of the audio signal changes (which happens with music.....), the moment of taking a sample also affects the amplitude. Now the amplitude of that sample can be described very well, using 16 bits in traditional audio.

The timing of taking subsequent samples however depends on the short term stability of the clock. When converting from digital back to analog, a timing error automatically leads to an amplitude error.

Jitter is a measure to express the short term accuracy of a clock, it is expressed in ps, mostly. Forget about ppm values, they are describing long term stability.

When using a CDP as a transport, lower jitter at the digital output also helps, as most DACs are still not imune enough to incomming jitter.

Hope this helps a little

 

[Bryan]

OK, that makes perfect sense...

Thanks for the lesson!

So then, how do I determine the quality of the existing clock, and if needed, go about changing units. Are the clocks "plug-and-play" type tweaks, or is it a more involved substitution which involves altering support circuitry to accomidate the new device?

Also, any info about opamps?

Would you know if it would be possible for me to contact NAD and request the schematic and/or service manual?

Thanks,

Bryan

 

[Guido Tent]

Re: OK, that makes perfect sense...

Thanks for the lesson!

So then, how do I determine the quality of the existing clock, and if needed, go about changing units. Are the clocks "plug-and-play" type tweaks, or is it a more involved substitution which involves altering support circuitry to accomidate the new device?

Also, any info about opamps?

Would you know if it would be possible for me to contact NAD and request the schematic and/or service manual?

Thanks,

Bryan

Bryan,

Most (nearly all) clocks in CD players are off the shelf designs which are not designed and implemented with real low jitter in mind. They can be bettered, hence will enhance playback.

Commercially available clocks can be implemented quite easilly, no changes needed except removal of crystal, mostly 2 capacitors and injecting new clock (which needs power supply as well, to be extracted from CDP).

I like AD797 and the OPA627

No clue on NAD, just try it and otherwise www.doknet.nl will work

 

[Bryan]

Were getting closer....

Guido,

What are the "best" available replacement's, and where does one source them? Is there ample support literature to guide one throught the implementation of the new clock?

Lets deal with the opamps later.....
I assume the above are your favorites.

How much money do clock replacements cost, and how long of a project is it to finish, 1 hour, 1 day, few days???

Also, does the new power supply come from tapping into an existing supply in the CDP, or is it built/added alongside during the clock swap? I assume this PS needs to be very clean?

Always learning more!!!

Thanks,

Bryan

 

[Guido Tent]

Re: Were getting closer....

Guido,

What are the "best" available replacement's, and where does one source them? Is there ample support literature to guide one throught the implementation of the new clock?

Lets deal with the opamps later.....
I assume the above are your favorites.

How much money do clock replacements cost, and how long of a project is it to finish, 1 hour, 1 day, few days???

Also, does the new power supply come from tapping into an existing supply in the CDP, or is it built/added alongside during the clock swap? I assume this PS needs to be very clean?

Always learning more!!!

Thanks,

Bryan

Bryan,

I propose you do a search on DIYaudio. There are many clocks available:

Trichord
Audiocom
Elso Kwak
LCaudio
TENTlabs

and probably more that I am not aware of

I haven't been able to compare them all soundwise, but by measurement I found differences. Pricewise they differ a lot, as well as the DIY level of what is delivered and required to mount them.

Power supply in general should be very clean, and adding seperate transformer / rectifier is recomended.

As I am one of the manufacturers, I will not comment any more, but I am sure other members may be of help.

 

[Bryan]

Guido,

Understood

I'll do a detailed search, and ask around for feedback.
I appreciate you getting me started.

If anyone else wants to add any more input, please do so.

Thanks All,

Bryan

 

[Ulas]

Re: Re: Ok... Lets focus on the NAD S500

The timing of taking subsequent samples however depends on the short term stability of the clock. When converting from digital back to analog, a timing error automatically leads to an amplitude error.

Well said. But the timing error and subsequent amplitude error is only significant if the amplitude of the digital sample can be reconstructed to exactly equal the amplitude of the original analog signal. It cannot.

First, the digital sampling, with a finite number of bits, cannot accurately represent an analog signal. There will be a sampling error in the range of +/- ½ LSB.

Second, most modern-day digital audio production adds dither to the signal, which amounts to another ½ to 1 LSB of random noise.

Third, DACs are rarely linear down to the LSB.

Fourth, the typical DAC settling time is usually far greater than any XO jitter.

Fifth, given the inherent jitter in any digital circuit, especially one implemented in slow HC logic I fail to see how a little XO jitter can be a bad thing.

In fact, the effects of jitter are really no different than the effects of dither; they both introduce a small random error to the reconstructed audio signal.

 

[Guido Tent]

Re: Re: Re: Ok... Lets focus on the NAD S500

Well said. But the timing error and subsequent amplitude error is only significant if the amplitude of the digital sample can be reconstructed to exactly equal the amplitude of the original analog signal. It cannot.

First, the digital sampling, with a finite number of bits, cannot accurately represent an analog signal. There will be a sampling error in the range of +/- ½ LSB.

Second, most modern-day digital audio production adds dither to the signal, which amounts to another ½ to 1 LSB of random noise.

Third, DACs are rarely linear down to the LSB.

Fourth, the typical DAC settling time is usually far greater than any XO jitter.

Fifth, given the inherent jitter in any digital circuit, especially one implemented in slow HC logic I fail to see how a little XO jitter can be a bad thing.

In fact, the effects of jitter are really no different than the effects of dither; they both introduce a small random error to the reconstructed audio signal.

Hi

My ears and measurements tell me that clock oscillator jitter still counts, at least improving the average oscillator in a CDP improves sound in my ears.

I am not refering to the lsb only, modern DAC are linear to and beyond 16 bits, which is on the disc, I do not expect more to come of.

Settling time is rather constant, though depends on (local) power supply variations, so I do not see the correlation with jitter you include here.

Oh, and the well know everywhere to find 121 ps jitter requirement is not valid. I dd some simple tests using a VCXO and well defined signals on the control port to show that.

best regards