PCM1702 sensitive to ESD?

klitgt · 10th February 2006, 01:45 PM

I plan to replace the PCM1702 J-grade with K-grade DAC chips in a Denon DCD2700 CDP.

1. Is this worth while?

2. Will the new 1702's die

if I solder them into the PCB without anti ESD protective devices?

Anyone has anything to say about changing DACs in general?

Charles Hansen · 12th February 2006, 02:18 AM

Don't bother. Most of the J-grade parts actually meet the K-grade specs. It's just that they are not *guaranteed* to do so. You won't notice any improvement, and it will cost a lot of time and money.

klitgt · 13th February 2006, 08:11 AM

Oh thank's! I also suspected this, but in a Danish forum some religious persons say it is a MUST to replace the J grades.

I stay with the J's!

Charles Hansen · 13th February 2006, 01:22 PM

Please remember that my opinion is just that -- an opinion. I have never directly compared the two in a strict listening test. We are a manufacturer and use the K-grade because people expect it in an expensive product. I know another manufacturer that uses a lower grade (I can't remember if it is J-grade or ungraded), and he claims there is no difference.

On the other hand, if the Danish person did a careful experiment then that could have more validity than my opinion. You would have to read many of his postings and try to decide if you think he is a careful experimenter and a good listener. I would be surprised if there is a meaningful difference between the two grades, but I have been surprised before!

anatech · 13th February 2006, 01:33 PM

Hi klitgt,
Just a note to say I haven't killed any DACs or other chips by removing and replacing them. As long as you are careful and your equipment (plus yourself) are referenced to ground through a resistor. 1 Meg ohm is normal. Also connect the equipment chassis to the same reference.

It's important to use a controlled temperature soldering station so you don't damage the PCB. Your method is as important as your equipment.

Try not to work with the power on!

-Chris

anatech · 13th February 2006, 01:37 PM

Hi Charles,
The PCM1702 is my current fav D/A chip. What would you say in your opinion are the better sounding chips? My Denon DCD-S10 uses two per channel, co-phased again then summed (stock).

I'm a bit out of touch these days.

-Chris

Bernhard · 13th February 2006, 01:55 PM

I have measured plain and J 1702.
They all vary a lot, no matter what grade and it is like coing to casino.
By the way IMHO 1702 is not very good at all.

Hurtig · 13th February 2006, 02:09 PM

I have recently changed a PCM1702 that had died.... I did it at home with no special ESD-care, and I had no problems.
But remember... Often ESD failure shows long time after the problem started. Typically the device will get a partial damage, and often it works fine for months. And then some day it quit.

The discussion about J and K-grade... Remember, that these are the same devices. A THD measurement decide if the device will get a white og red dot (J or K-grade).
In real life applications it don't think you will notice any difference. Often the analog stage after the PCM1702 is much worse than the worst grade of PCM1702.

Have anyone made some serios testing of PCM1702 vs PCM1704. They are almost pin-compatible... Just remember that the digital supply is swapped.

Bernhard · 13th February 2006, 02:31 PM

Quote:

Originally posted by Hurtig
A THD measurement decide if the device will get a white og red dot (J or K-grade).
In real life applications it don't think you will notice any difference. Often the analog stage after the PCM1702 is much worse than the worst grade of PCM1702.

Not for low level dist.
Also I believe the chips tend to change performance after time.
So grades are not worth a penny.
In some datasheets you can read about additional burn-in screening beeing offered, which means that the chip will be tested after burn-in wether it still meets grade specs or not.

Jocko Homo · 13th February 2006, 02:58 PM

The low-level performance of all the '170x DACs isn't that good. Does not matter what (if any) letter they stick on the end.

As for ESD.........they seem rugged, unlike the AD1862. Great low-level performance, a lot died in the field, though.

Jocko

10th February 2006, 01:45 PM	#1
klitgt diyAudio Member Join Date: Sep 2004 Location: Denmark	PCM1702 sensitive to ESD? I plan to replace the PCM1702 J-grade with K-grade DAC chips in a Denon DCD2700 CDP. 1. Is this worth while? 2. Will the new 1702's die if I solder them into the PCB without anti ESD protective devices? Anyone has anything to say about changing DACs in general?

13th February 2006, 02:58 PM	#10
Jocko Homo Banned Join Date: Feb 2002 Location: As far from the NOSsers as possible	Casino.........I like that....... The low-level performance of all the '170x DACs isn't that good. Does not matter what (if any) letter they stick on the end. As for ESD.........they seem rugged, unlike the AD1862. Great low-level performance, a lot died in the field, though. Jocko

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12th February 2006, 02:18 AM	#2
Charles Hansen diyAudio Member Join Date: May 2003 Location: Colorado	Don't bother. Most of the J-grade parts actually meet the K-grade specs. It's just that they are not guaranteed to do so. You won't notice any improvement, and it will cost a lot of time and money.

13th February 2006, 08:11 AM	#3
klitgt diyAudio Member Join Date: Sep 2004 Location: Denmark	Oh thank's! I also suspected this, but in a Danish forum some religious persons say it is a MUST to replace the J grades. I stay with the J's!

13th February 2006, 01:22 PM	#4
Charles Hansen diyAudio Member Join Date: May 2003 Location: Colorado	Please remember that my opinion is just that -- an opinion. I have never directly compared the two in a strict listening test. We are a manufacturer and use the K-grade because people expect it in an expensive product. I know another manufacturer that uses a lower grade (I can't remember if it is J-grade or ungraded), and he claims there is no difference. On the other hand, if the Danish person did a careful experiment then that could have more validity than my opinion. You would have to read many of his postings and try to decide if you think he is a careful experimenter and a good listener. I would be surprised if there is a meaningful difference between the two grades, but I have been surprised before!

13th February 2006, 01:33 PM	#5
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi klitgt, Just a note to say I haven't killed any DACs or other chips by removing and replacing them. As long as you are careful and your equipment (plus yourself) are referenced to ground through a resistor. 1 Meg ohm is normal. Also connect the equipment chassis to the same reference. It's important to use a controlled temperature soldering station so you don't damage the PCB. Your method is as important as your equipment. Try not to work with the power on! -Chris

13th February 2006, 01:37 PM	#6
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Charles, The PCM1702 is my current fav D/A chip. What would you say in your opinion are the better sounding chips? My Denon DCD-S10 uses two per channel, co-phased again then summed (stock). I'm a bit out of touch these days. -Chris

13th February 2006, 01:55 PM	#7
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	I have measured plain and J 1702. They all vary a lot, no matter what grade and it is like coing to casino. By the way IMHO 1702 is not very good at all.

13th February 2006, 02:09 PM	#8
Hurtig diyAudio Member Join Date: Feb 2005 Location: Denmark - Århus	I have recently changed a PCM1702 that had died.... I did it at home with no special ESD-care, and I had no problems. But remember... Often ESD failure shows long time after the problem started. Typically the device will get a partial damage, and often it works fine for months. And then some day it quit. The discussion about J and K-grade... Remember, that these are the same devices. A THD measurement decide if the device will get a white og red dot (J or K-grade). In real life applications it don't think you will notice any difference. Often the analog stage after the PCM1702 is much worse than the worst grade of PCM1702. Have anyone made some serios testing of PCM1702 vs PCM1704. They are almost pin-compatible... Just remember that the digital supply is swapped.