if I solder them into the PCB without anti ESD protective devices?
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!
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!
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
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
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.
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.
Hurtig said:
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.
Are there any sources left for AD1862? I'm thinking about building a DAC and can't decide between PCM1704, AD1862 and PCM1794.... The 1794 is really easy to implement compared to 1704 and has really good specs.. but the fact that it is some kind of heavily modified sigma delta with an integrated digital filter makes me suspicious.
I have the same reservations. My sources at BB tell me to think of a '179x as more of a DSP chip than a DAC. Supposedly, they do some clever things inside. Some more for their benefit than ours.
The thing that looks most interesting is the current output. Hot enough to actually realise the dynamic range of the DAC. Hopefully, it looks better than the '170x.
Only source of '1862s for me is the pull-out bin. If a unit comes back with a dead one, I upgrade the unit to '1704s, and keep the working ones for guys who won't upgrade.
Jocko
The thing that looks most interesting is the current output. Hot enough to actually realise the dynamic range of the DAC. Hopefully, it looks better than the '170x.
Only source of '1862s for me is the pull-out bin. If a unit comes back with a dead one, I upgrade the unit to '1704s, and keep the working ones for guys who won't upgrade.
Jocko
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