As noted earlier, it was the first gen. Bitstream DAC -- specifically noise-shaping -- that convinced Rob Watts (Chord digital designer) that digital was a viable alternative to vinyl. Take Watt's comments for whatever it's worth. He has said it in various video seminars and interview on YouTube; I think I posted a few video links to the noise-shaping comment in another thread, including:
https://www.diyaudio.com/community/threads/xmos-xu208-or-amanero-usb.323116/post-7276885
Watt's implements Chord digital filters and d/a all in FPGA. He supposedly has been working on digital filters and d/a algos since the early 1980s.
Myself, having worked in the industry (but not audio), I'm not sure FPGA -- even with latest fast chips -- is the best way to approach audio. ASICs are probably still optimal.
About "overromanticising" old tech. Indeed part of may be boredom ... just need a change of pace, regardless of sound quality. That said, forum like SBAF do active threads that compare old dacs and CDPs (Mark Levinson) to latest high-end R2R or DS dacs. And compare and contrast the results.
And the subjective tests are a mixed bag.
https://www.superbestaudiofriends.org/index.php?threads/marveys-dac-chart-of-awesomeness.63/
Last edited:
Can someone point themselves to the OP's interest in finding the reason why they sounded different, while nobody can point to an exact measurement result that explains that, and also point themselves to the fact that the OP wasn't interested in arguing about what supposedly can not be heard?
Seems to me that that is the only thing here being off-topic.
Peace out.
On-topic, as far as I'm concerned:
HQPlayer has many filters and modulators to process musical data. My best experience has been with a Twisted Pear Chronus together with a Beaglebone and Botic driver.
It is really easy to pick out the differences between the modulators. I've measured them many times, noise, thd etc can differ a little bit, but the SQ ranges from thicker, noisier, more laid back, to a thinner sound, more clean, more detail brought up front etc.
I am guessing the 2nd gen Sony's had just a lot better processing (dither etc.as mentioned here before), the power supply had incorporated a few more years experience, as well as the output stage. We'll never know for sure unless we change these parts with 1st gen parts, or one is sure the only difference between 1st gen and 2nd gen was the processor on the pcb.
No chance that is the case.
Seems to me that that is the only thing here being off-topic.
Peace out.
On-topic, as far as I'm concerned:
HQPlayer has many filters and modulators to process musical data. My best experience has been with a Twisted Pear Chronus together with a Beaglebone and Botic driver.
It is really easy to pick out the differences between the modulators. I've measured them many times, noise, thd etc can differ a little bit, but the SQ ranges from thicker, noisier, more laid back, to a thinner sound, more clean, more detail brought up front etc.
I am guessing the 2nd gen Sony's had just a lot better processing (dither etc.as mentioned here before), the power supply had incorporated a few more years experience, as well as the output stage. We'll never know for sure unless we change these parts with 1st gen parts, or one is sure the only difference between 1st gen and 2nd gen was the processor on the pcb.
No chance that is the case.
In that video he talks about Bitstream being 256fs. Afaik the TDA1547 could only manage 192fs.
Either he is wrong, I am mistaken or he based his experience on something else than 1st gen Philips Bitstream players.
Wouldn't be the first.
I remember DSD being raved about by first listeners, while later it turned out it was the DSD-Wide format they listened to which sadly didn't come to market.
DSD Wide, also known as PCM narrow? 
The first generation Philips bitstream DAC appears to be the SAA7320, https://www.datasheetarchive.com/pd...5f8c80260b3391a6f0548ab39&type=O&term=SAA7320
According to its January 1988 datasheet, it uses 256 times oversampling, second-order noise shaping and a switched-capacitor DAC.
The first generation Philips bitstream DAC appears to be the SAA7320, https://www.datasheetarchive.com/pd...5f8c80260b3391a6f0548ab39&type=O&term=SAA7320
According to its January 1988 datasheet, it uses 256 times oversampling, second-order noise shaping and a switched-capacitor DAC.
Last edited:
It gets much better than that, trust me. I bought the various diy options out there and tried them before eventually designing my own. Wasted some money finding out what didn't work all that well until finally deciding to do it diy, more or less from scratch.
I took the newer dac as it seemed to me this would be the fastest of any predecessor, besides not knowing which was the first one, haha;-)DSD Wide, also known as PCM narrow?
The first generation Philips bitstream DAC appears to be the SAA7320, https://www.datasheetarchive.com/pd...5f8c80260b3391a6f0548ab39&type=O&term=SAA7320
According to its January 1988 datasheet, it uses 256 times oversampling, second-order noise shaping and a switched-capacitor DAC.
I still think this didn't happen though, does anybody know a Philips cdplayer that had a 22MHz clock? I can't remember ever seeing one from the insideor a schematic, but that is one of the players I hardly saw for repairs. Can be just me.
Mea culpa, I made a calculus error, you're right of course.
Btw, here's the datasheet:
https://datasheet4u.com/mobile/1305402/SAA7320.html
Btw, here's the datasheet:
https://datasheet4u.com/mobile/1305402/SAA7320.html
Probably Watts is wrong. But thinking about sampling and bit rate, purely as the-higher-the-better , is not optimal. The first gen TDA1540 dac could only do 14-bits, but it may have been so optimized for 14 bits, so that handled it data and throughput easily and effortlessly. In certain ways, and all else held equal, the 1540 outperformed the successor 1541 (and beyond).
It's confusing to conflate DSD with Bitstream/MASH/DS. DSD is SACD and high-rez digital audio in a type of pulse-density modulation. See: https://en.wikipedia.org/wiki/Direct_Stream_Digital
Technically, with DSD (SACD), you don't need a DAC. Just a LPF.
First gen Bitstream was SAA7320 and that indeed was 256fs. But TDA1547 was designed for use (originally) with SAA7350 which uses a 3rd order modulator (SAA7320 being 2nd order) so it wasn't necessary to have such high levels of OS.
Indeed after 7321 there was 7323, I still have a few samples in my box, albeit with bent leads after so many years.
DSD (real DSD, not DSD Wide/PCM narrow) is a single-bit sigma-delta modulate, which is a kind of time-discrete pulse density modulation. The exact same holds for the output signal of a bitstream converter. The only difference is that DSD is transported as a sigma-delta modulate, not as PCM and then converted to a sigma-delta modulate in the DAC.
If you want acceptable sound, you need something with a very reproducible and low-noise high and low level to drive the filter. You also have to make sure that differences between the transitions between high and low and between low and high don't affect the sound and you have to be very careful with the phase noise floor. The resulting circuit is usually called a single-bit DAC. It can be as simple as a flip-flop with a clean supply and ground, but it can also be much more complicated than that. The exact same that holds for DSD holds for bitstream or for any other single-bit sigma-delta (a.k.a. delta-sigma) modulate.
Last edited:
