OK, I promise I searched, but I just couldnt find out the exact answer to my question: I have a cd player that I plan to put an upsampling DAC on that reads at 192Khz. My question is, is a HDCD transport different than a normal CD Transport, and if it is not, then if I put a upsampling DAC in this cd player, will it actually play the HDCD information. If it is, then how difficult is it to put a new transport in a cd player and have it still run off of the same controls as the original one so that I will actually have an HDCD player that upsamples regular CDs. I would try to get a HDCD player, but this is a modification to my car cd player, and I dont know of any car audio cd players that do HDCD, and I would like to do this in the spirit of learning about these things. Thank you very much
>>My question is, is a HDCD transport different than a normal CD Transport, and if it is not, then if I put a upsampling DAC in this cd player, will it actually play the HDCD information.
The answer to the first part is no. HDCD doesn't refer to a transport. It is a digital filter which operates on the CD bitstream. An HDCD disc will play on ANY CD player, however HDCD decoding will only occur in a unit which features the HDCD decoder.
To an ordinary CD player, the HDCD bitstream looks just like any other bitstream. Only units with the HDCD decoder can identify an HDCD bitstream.
When you say "play the HDCD information", I assume you mean decode it for playback. The DAC comes after the decoder, so it is feasible that the DAC could upsample the data at an incoming bistream rate of:
44.1kSamples/sec. * 16bits
Note that in some units the HDCD decoder in integrated into the DAC. Burr-Brown (now part of Texas Instruments) does this. If your upsampling DAC contains the HDCD filter, you'd be in business.
>>If it is, then how difficult is it to put a new transport in a cd player and have it still run off of the same controls as the original one so that I will actually have an HDCD player that upsamples regular CDs.
The transport alone has no effect on HDCD decoding.
Are you actually referring to swapping the transport, servo controller, decoder IC, and the DACs? In this case, getting the buttons to work is a trivial exericse, assuming the CD player firmware supports all the functions of the buttons on the new unit.
The answer to the first part is no. HDCD doesn't refer to a transport. It is a digital filter which operates on the CD bitstream. An HDCD disc will play on ANY CD player, however HDCD decoding will only occur in a unit which features the HDCD decoder.
To an ordinary CD player, the HDCD bitstream looks just like any other bitstream. Only units with the HDCD decoder can identify an HDCD bitstream.
When you say "play the HDCD information", I assume you mean decode it for playback. The DAC comes after the decoder, so it is feasible that the DAC could upsample the data at an incoming bistream rate of:
44.1kSamples/sec. * 16bits
Note that in some units the HDCD decoder in integrated into the DAC. Burr-Brown (now part of Texas Instruments) does this. If your upsampling DAC contains the HDCD filter, you'd be in business.
>>If it is, then how difficult is it to put a new transport in a cd player and have it still run off of the same controls as the original one so that I will actually have an HDCD player that upsamples regular CDs.
The transport alone has no effect on HDCD decoding.
Are you actually referring to swapping the transport, servo controller, decoder IC, and the DACs? In this case, getting the buttons to work is a trivial exericse, assuming the CD player firmware supports all the functions of the buttons on the new unit.
Are you sure about the Burr-Brown information? I'm not aware of any HDCD filter from B-B. Maybe they made one in the past?
The best way to get into the HDCD business is to buy a second-hand HDCD player with the PMD-100 or PMD-200 digital filter, and remove it for your own purposes.
PS: HDCD really does sound better. But in a car?
PPS: gig 'em
The best way to get into the HDCD business is to buy a second-hand HDCD player with the PMD-100 or PMD-200 digital filter, and remove it for your own purposes.
PS: HDCD really does sound better. But in a car?
PPS: gig 'em
Thanks for all the info...Now that I started looking more into it, the DAC design I am using does not have a HDCD Decoder in it. I guess I'll have to find one of the chips that were mentioned that will work for me. Do any of you have a design for a HDCD decoder? I have found many different DAC designs, but so far havent found any HDCD decoders, only upsampling units. Perhaps I am just looking in the wrong spots. And yes, I realize it might be a little extreme to do this in a car, but that is exactly what i'm going for, and I am positive that this will pay off in the end.
Pacific Microsonics does not provide any documentation on their filters, but I once found a schematic on the Burr-Brown website that describes the pinout and function of the PMD100.
http://www-s.ti.com/sc/psheets/sbau029/sbau029.pdf
I saved it locally in case they decide to remove it from their website some day.
http://www-s.ti.com/sc/psheets/sbau029/sbau029.pdf
I saved it locally in case they decide to remove it from their website some day.
No, they never made an HDCD decoder, but earlier BB dacs (PCM1702 etc) were fairly commonly used with the Pacific Microsonics PMD-100 HDCD digital filter. The current implementation is the PMD-200 which IIRC is implemented via generic dsp.. Incidentally Microsoft now owns the rights to HDCD technology and licenses it to manufacturers that are interested in using it.
Microsoft WMP also supports HDCD decoding, not enabled by default. (I can't remember if HDCD playback capability came native or as an add on, but having largely left the windows world I am not in a good position to check.)
Strangely enough there are a surprising number of HDCDs in circulation with absolutely no identification of the fact that they are HDCD. (I have a bunch of them) Unfortunately my current DIY dac does not support HDCD decoding, at some point I will design a new one that hopefully does.
I had a PSA Ultralink II that decoded HDCD using the PMD-100 and Ultra-Analog dacs, I got rid of it when my modded Zhaolu 2.5A ended up sounding better on most non HDCDs than it did. The current dac is a big improvement over that, now if it only supported HDCD... (HDCDs did sound a lot better which based on more current dac experience leaves me wondering if standard CD playback on the Ultralink II was deliberately so much worse???)
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This Classe CDP10 used the PMD200 and then used 2 x PCM1738's in quad diff output it has 8 x i/v amps!!!!.
I also have a Cal CL15 that uses the PMD100 with dual PCM1702's
Red Book verses HDC the Classe CDP10 has a bigger difference between the two discs. The PMD200 showing it's better sounding and has the bigger difference than the PMD100.
Yet on Red Book only, the CAL CL15 has more detail more drive/punch goes lower has more dynamics and seems just as sweet as the Classe. Both machines are direct coupled from dacs to I/V's to buffers to output. I think someone here said the PCM1738E was a Delta Sigma, I must just have a personal preference for Multibit dacs verses Delta Sigma dacs then.
Cheers George
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I was dead wrong, shortly after posting this I discovered that they had indeed made a dac chip with integrated HDCD digital filter (PCM1732) - and it seems to have been used in a lot of different places as well. I did not have spare time to come back and apologize for my error - guess it would have paid to double check..
Best I can tell it does appear to have been discontinued as it is not listed in the current TI production database, although there are many references to it online..
This could have been a great dac, except that it is voltage output dac and doesn't have current output taps.
Usually find the integrated I/V stages to be inferior to what one can do externally. They commonly use something like NE5534 as internal I/V stages.
Cheers George
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