Going a little off topic now, but I have just bought a Cambridge Audio DACMagic II on ebay for £42.00, I have it here now, and have to say it sounds quite good, although so far, the only transport I can use with it is my DVD drive in my PC as my CD player has a BNC out and I don't have any cables that wil fit yet (only an optical one, which I can connect to my PC's soundcard).
But what I was wondering is does anyone know if this is a truelly differential DAC design, or does it just a take a single channel output from a DAC chip and split it to produce the ballanced output on the back (I haven't tried it with the balanced connections yet, as I still need to build an amp that will accept them).
If anyone can answer this I would be quite interested to know (or hear any info on this DAC in general), as this will now be refference to try and beter and I would like to know a little about it before I criticaly comare it to somethig I have built myself.
But what I was wondering is does anyone know if this is a truelly differential DAC design, or does it just a take a single channel output from a DAC chip and split it to produce the ballanced output on the back (I haven't tried it with the balanced connections yet, as I still need to build an amp that will accept them).
If anyone can answer this I would be quite interested to know (or hear any info on this DAC in general), as this will now be refference to try and beter and I would like to know a little about it before I criticaly comare it to somethig I have built myself.
Re: Re: New ACG design uses CS43122
I am 4-6 weeks away from having first PCBs so right now there is nothing to take pictures of. I have posted images of the PCB. Here is one showing three of the four layers (top signal, bottom signal, power, and top component placement; ground not shown).
The functional prototype for XD0 is the 24 bit 96k upgrade to X-DAC 3.0 called X-DAC 3.24. Here is a picture of X-DAC 3.24.
Details of how X-DAC 3.24 evolved are on my R&D page.R&D page
When XD0 is completed it will be finished to a standard like my X-DAC 3.0 Signature shown below.
happy listening (and soldering)!
I am 4-6 weeks away from having first PCBs so right now there is nothing to take pictures of. I have posted images of the PCB. Here is one showing three of the four layers (top signal, bottom signal, power, and top component placement; ground not shown).
An externally hosted image should be here but it was not working when we last tested it.
The functional prototype for XD0 is the 24 bit 96k upgrade to X-DAC 3.0 called X-DAC 3.24. Here is a picture of X-DAC 3.24.
An externally hosted image should be here but it was not working when we last tested it.
Details of how X-DAC 3.24 evolved are on my R&D page.R&D page
When XD0 is completed it will be finished to a standard like my X-DAC 3.0 Signature shown below.
An externally hosted image should be here but it was not working when we last tested it.
happy listening (and soldering)!
Norman, I always loved the MMCX (I think?) terminated coax in your X-DAC prototype. I copied it in my DAC for carrying around the 300mV sine wave from the clock module. It looks like there are at least six more sites for coax connectors (shaped like the 5-side of a die). Are these test points or what?
Hi all,
I did not read all posts in this thread
If I had to start right now I would take AD1955
Forget about Application and Demo boards of manufacturers They give a fast start but no good sound, not to mention the lousy board layout (I have not yet see decent ones).
I tend to design something like a double layer board with SMD based shapes for the major components like input receiver, digital filter and 2 DACs, does something exist already ?
succes
I did not read all posts in this thread
If I had to start right now I would take AD1955
Forget about Application and Demo boards of manufacturers They give a fast start but no good sound, not to mention the lousy board layout (I have not yet see decent ones).
I tend to design something like a double layer board with SMD based shapes for the major components like input receiver, digital filter and 2 DACs, does something exist already ?
succes
Hi, if you are talking about any design that I have started, no (I got a little distracted the other day when my two giant transformers turned up for the large monoblocks I aam wanting to build) but I had almost settled on the idea of using a crystal CS43122 allong with a one of their input recievers for the main parts in the design. As, this seams to be a nice simple unit for me to start out with (no microcontroler required, and it comes in a larger surfcae mount packeage than most otheres which is nice for me as I have never done any SMD soldering before). Although, if the burr brown PCM1792 still isn't available by the time I get enough free time to have a go at a second design, I would probably consider the AD1955, as they seem fairly well matched for features.
Andrew.
One more thing, which I have forgotten to ask up till now, is this:
If I use two or more of the current output DACs in parallel, will the performance of the overall design be significantly inmproved (I imagine that it would allow the S/N ratio and dynamic range for the out put stages to be more easily attained).?
Andrew.
One more thing, which I have forgotten to ask up till now, is this:
If I use two or more of the current output DACs in parallel, will the performance of the overall design be significantly inmproved (I imagine that it would allow the S/N ratio and dynamic range for the out put stages to be more easily attained).?
bigparsnip said:
Andrew,
You may win 3 dB
I do not like paralleling the devices as you have to drive more (clock) gates etc
Put money and effort in (low noise) power supplies, componets and low jitter (PLL, reclocking etc)
http://members.chello.nl/~m.heijligers/DAChtml/dactop.htm
succces
Guido Tent said:
Hi Guido,
Can you give good reasons for choosing this one? Curious about.
I am fiddling around for a new DAC design and up to now I am at the PCM1704’s for it. Two of them per channel in balanced mode and transformer coupled out. Besides tackling jitter, a good I-V converter stays the trickiest part.
Cheers
HeadSh0T said:
One reason why TDA1541 sounds so good, might be that it uses switched current sources for most of the bits, which means that the output current is the sum of paralleled currents that directly come from somewhere.
By the way of comparison, a R2R DAC has that ladder network and this is a large number of resistors, current flows through chains of resistors which might not be healthy for sound.
Resistor noise & thermal voltages will add up.
Could be compared like R2R is a long chain of resistors on a pcb, connected with lots of solder joints in the signal path, and TDA1541 is a pcb with a number of paralleled resistors.
So maybe from this point of view, parallel R2R DACs could really sound better...
TDA1541A vs CS, AD, BB chips
I am upgrading my Philips CD753 player. Originally I planned to put there a new DAC card with CS8414 + CS4397 and connect it through SPDIF. There is other solution: change the TDA1549T DA converter chip to the TDA1541A or TDA1541AS1(connect it directly to the serial output of CD drive) make some new output circuit(I/V, filtering, buffering..). Which is a better solution? Can I get the maximum from the CD with TDA1541? Is there any advantage of the CS4397 or AD1852/53 compared to TDA1541A?
Which opamps do you recommend for I/V conversion?
Thank you!
Frank
I am upgrading my Philips CD753 player. Originally I planned to put there a new DAC card with CS8414 + CS4397 and connect it through SPDIF. There is other solution: change the TDA1549T DA converter chip to the TDA1541A or TDA1541AS1(connect it directly to the serial output of CD drive) make some new output circuit(I/V, filtering, buffering..). Which is a better solution? Can I get the maximum from the CD with TDA1541? Is there any advantage of the CS4397 or AD1852/53 compared to TDA1541A?
Which opamps do you recommend for I/V conversion?
Thank you!
Frank
AD1955 vs. AD1852
Hi,
as I've mentioned in another thread :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=17119&perpage=10&pagenumber=2
by now, bearing in mind design differencies, AD1852 outperforms AD1955. Yes, I wonder why is it so!
Hi,
as I've mentioned in another thread :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=17119&perpage=10&pagenumber=2
by now, bearing in mind design differencies, AD1852 outperforms AD1955. Yes, I wonder why is it so!
Hi,
did many comparisons of different DACs and Eval-Boards.
My favourites are the TI/BB PCM1794A, very closely followed by the AD1955 and the PCM1796A, if You could bypass it´s digital filter. All chips running onn 24Bit/176 or 192kHz.
The PCM1704 was the best R2R DAC but sounds a bit grainy compared to the above mentioned chips. Cost of the chip is very high.
Haven´t compared the ESS-DACs yet, which offer some interesting features, but are expensive too and the company´s support policy is ridicolous.
The sonic differences between actual DAC chips are quite small. Peripheral circuits like the digital filters and analogue stages show greater influence on sound. For a good sounding DAC-board the actual DAC-chip is of lower interest.
jauu
Calvin
did many comparisons of different DACs and Eval-Boards.
My favourites are the TI/BB PCM1794A, very closely followed by the AD1955 and the PCM1796A, if You could bypass it´s digital filter. All chips running onn 24Bit/176 or 192kHz.
The PCM1704 was the best R2R DAC but sounds a bit grainy compared to the above mentioned chips. Cost of the chip is very high.
Haven´t compared the ESS-DACs yet, which offer some interesting features, but are expensive too and the company´s support policy is ridicolous.
The sonic differences between actual DAC chips are quite small. Peripheral circuits like the digital filters and analogue stages show greater influence on sound. For a good sounding DAC-board the actual DAC-chip is of lower interest.
jauu
Calvin
It is not easy to compare R2R DACs with other kinds like "continuous calibration" (TDA1305, AD1955) and several sigma-delta (Cyrrus logic CS4396, PCM1715U), because top quality I/U converter still needed. If you use OP-Amps for I/U like OPA627/AD844, still grainy sound is present.
With discrete MOSFET I/U approach like that one from Mr. Nelson Pass (Pass D1) you will get best results with R2R topology. In all the other cases PCM63-PCM1794 isn't best choice - then AD1955 (sometimes even a cheap TDA1305) is clearly better.
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