here are some comments from the SD folks on the A/D chip in the V3 vs the 722/744T, taken from the SD support forum. Of course, the A/D chip itself is only part of the story, implementation has a lot to do with how things eventually sound, but I thought it was interesting:
>The V3 uses a PCM1804 from TI, and the 744 uses a CS5361. As a side note - we started this design with the 1804, but it turned out to be such a poor chip in almost every regard, we sold them all back to TI and switched to the much better, cleaner 5361. It is quieter, lower distortion, lower group delay, draws less current, has MUCH better anti-aliasing at higher sample rates, and has no idle tones, and most importantly, sounds much better.<
FWIW.
Steve
marc laughs ass OFF. 
Todd laughs ass off upon hearing Marc finding justification when the Sound Devices design engineer claims his component selection is be better than his competitors.
Did you think he'd say, oh I picked crappy parts for my design?
Ok, so I looked these up a bit to compare:
Claim:
- Cirrus CS5361 (722) is quieter - DOUBTFUL, but maybe true. The CS5361 and the TI PCM1804 both have minimum A-weighted Dynamic range of 106db. The CS5361 claims "typical" operation at 114db, while the PCM1804 on claims 112db "typical" operation. Even if these typical values are true, that isn't much in the way of a whopping difference. [BTW, semiconductor mfgs only need to meet min and max performance levels. Typical values are only marketing claims and should be taken with a huge grain of salt.]
- CS5361 is lower distortion - again, maybe. The CS5361 and the PCM1804 both have maximum THD+Noise of -95db. The CS5361 claims with "typical" operation THD+Noise is no more than -105db; the PCM1804 only claims typical THD+Noise to be -102db. Once again, even if true, not much of a difference.
- CS5361 has much better anti-aliasing at higher sampling frequencies. True, but very misleading. The CS5261 and the PCM1804 have identical anti-aliasing specs for 44k, 48k, and 96k operation. The CS5361 only exceeds the PCM1804 at 192kHz operation -- only the highest sampling frequency, not "higher" frequencies. So unless you're recording 24/192, you won't see a difference.
- CS5361 has lower group delay. True. Frankly, I don't know what practical effect group delay has. Guess it's time for more research.
- CS5361 draws less current. YES. The cs5361 draws only 135mW, compared to 225mW for the PCM1804. From our standpoint, this means the 722 will get better battery life. My bet is that this is exactly why the design engineer chose this part of the TI part. All the rest is marketing fluff. Power management, esp for portable products, is a HUGE concern to design engineers. These are high current draw devices to begin with, much moreso than most of the rest of the components used. Saving 30% here is a big savings.
- CS5361 sounds much better. One man's opinion, and a very, very biased opinion at that.
So much for all his claims. I think the real statement should have been more like this:
The V3 uses a PCM1804 from TI, and the 744 uses a CS5361. As a side note - we started this design with the 1804 way back when we started the 722 project, but since we were way, way, way behind schedule, we were able to use the CS5361 that only came out in late 2004. This was a great opportunity, since it draws less current and totally saved our asses, since we had already gone way beyond on our power consumption in the rest of the design. We had all those TI PCM1804's sitting around in the stock room which we couldn't put to use since we totally missed our design targets. Since we had no money coming in from this project and since the TI parts were in high demand and limited supply, we sold them all back to TI which really helped with our quarterly earnings, which were really sagging since we were way, way, way behind with getting the 722 to market.
Topic: V3 vs 722/44 A/D (comments from SD) (Read 15559 times)