replace a DAC (the chip)????

Jan 12, 2003 at 7:22 PM Thread Starter Post #1 of 16
robert

robert

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just saw the AD8620 thread. which raises the question: are DACs pin compatible, and therefore replaceable?? and if so, any notion what might be better than the BB PCM63?? had a look at the TI/BB site a while back. the PCM63 has been obsoleted for some time.

robert
 
Jan 12, 2003 at 7:52 PM Post #2 of 16
Nope, you can't replace the DAC chip as almost every single chip has a different pin layout.

The PCM63 may be old and discontinued (and a few modern DAC's have better paper specs) , but it is still probably the best sounding 44.1/16 redbook DAC chip ever made. It's also the most expensive DAC chip ever made; it was probably discontinued because of its high cost rather than inferior performance...
 
Jan 12, 2003 at 9:10 PM Post #4 of 16
the only DAc chips I know that are pin-for-pin direct replacements are the AD1860/1851/1861 with the AD1860 being discontinued.

The PCM1702/04 may be , Iwould have to check my data sheets.

but if changing the chip is really important I see no reason you could't make an adapter board for the replacement. I remember seeing a webpage devoted to a universal DAC board with adapter for each DAC tried

Quote:

do you have any info about the pcm66p (the one in d-25 ) I can not find the specs anywhere....


Are you sure it is a PCM66 and not 56 ?
 
Jan 13, 2003 at 1:00 AM Post #7 of 16
just a senior moment: the 66 is from the d-25; the 63 is (if memory serves
eek.gif
) in my adcom 600 dac. it's the d-25 that i'd experiment with. the 66 isn't on the TI/BB site at all. a few sites list them as available, but don't show specs.

sorry about my confusion

robert
 
Jan 13, 2003 at 1:44 AM Post #8 of 16
There are DAC chips which are interchangeable - CS4328/4329 and 4390 were. So are CS4396/97/122. Also AD1866 and AD1868. I'm sure there are some BB that fit this category too.

Almost all chips are however SMD and replacing one with another is not something to be attempted without SMD rework workstation. It's fine and dandy to risk something cheap but if the unit was worth anything before - and if one contemplates replacing chips it probably was - then it's a risk one shouldn't take.
 
Jan 13, 2003 at 4:59 PM Post #10 of 16
Quote:

the 66 IS either a 63 or 56 , just that the package is an OEM part


According to icmaster.com (an online IC parts search database) these are all separate Burr Brown (now TI) parts. The PCM56 and PCM66 are listed as 16-bit devices, with power dissipations of 260 mW and 50 mW, respectively. The PCM63 is of course a 20-bit device.
 
Jan 15, 2003 at 1:43 AM Post #11 of 16
Quote:

There are DAC chips which are interchangeable - CS4328/4329 and 4390 were. So are CS4396/97/122. Also AD1866 and AD1868


AOS,
Have you tried the AD1868? It's numbers are slightly better than the AD1866 I think.

Stu
 
Jan 15, 2003 at 6:53 PM Post #12 of 16
1868 is 18-bit and I'm not aware of a digital receiver that can deliver 18 bits- it's usually either 16 or 24. Filter chips can do that which makes sense as AD1868/6 are supposed to be used with digital filters anyway. So for me personally AD1868 has no appeal.
 
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