Probably because of the DC Offset, I havent tested it though
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Probably because of the DC Offset, I havent tested it though
Following middachten's post above, I've ordered an OP249. Should have it in a week or so. I'll post how this goes and maybe a follow up post with the OpAmps and Tube combinations I have for reference.
Anyway, regards JITTER and the TubeMagic I've read a few posts on other forums that Airport Express jitter is very high and that ideally a DAC-subsystem that can re-clock the signal is best i.e. either get a standalone re-clocker + DAC - OR buy a DAC with an in-built re-clocker (like the Benchmark).
In my understanding all Delta Sigma based dac chips reclock which is why some claim there is not as much benefit between transports. R-2R based chips on the other hand are not as advanced for better or for worst.
Sorry ninjikiran - you lost me lol
If you can dumb-it-down that'd help - in essence, are you saying that the D1 is an R-2R based design and as such would need something like attenuated 3db's Teralink X2 to reclock the jitter from the Airport Express (Optical) which might alter (improve) the performance/output of the audio before it gets to the DAC, whereas other DAC's that DO reclock aren't going to show a huge difference by having an additional box added to handle the jitter because there's not so much gain to be had by changing the 'reclocking part' of the setup (i.e. by adding a Teralink X2). Also, can you elaborate on your comment about not handling the jitter 'for better or worse' as this jitter-surpression is all quite new to me and I'm struggling to understand the pro's and con's. In the meantime, I'll keep trawling the web and keep reading
attenuated 3db - I'm intreagued by the Teralink X2 and remember you mentioning something to me before either in an earlier post or PM - since the Airport Express uses an optical/toslink out to the DAC, will there be any/much of a gain to your knowledge or in your experience?
Maybe instead of reclock I am thinking about upsampling which according to most threads really diminish the advantages of a good transport as it reduces jitter intrinstically. When people start talking about these huge differences in transports I tend to get weary of whether somethings being attenuated somewhere. They should in theory do one and only one thing, provide the cleanest digital signal such that your dac can do its job properly.
The D1 is based off of a Cirrus Logic chip, meaning it is Delta Sigma.
I couldn't explain the concept of Delta Sigma, but R-2R ladders is a classic way of converting any digital signal to an analog signal through as series of resistors.
Thanks for the reply ninjikiran,
So with your comment:
and earlier comment:
So......Delta Sigma based DAC's such as the D1 reclock, BUT according to attenuated 3db's assertion
....the D1 DOESN'T reclock.
I suppose what I *really* need to know is - irrespective of whether or not the D1 does/doesn't reclock - would I benefit from yet another box (arghhhh) to combat the jitter from the Airport Express. Looking at attenuated 3db's comments that the Teralink made a HUGE difference, I thought I should consider something that will reduce jitter that can take in an optical signal and output an optical/coax signal for the D1.
I've not found anything particularly cheap in my short time of looking but the Monarchy Audio DIP has been reviewed as having made a substantial difference (to certain setups). Ideally I'd like to get hold of one to experiment for myself, but they seem as rare as hens teeth on the pre-loved market.
Any thoughts/comments to the above?
Thanks again guys,
I'll give it a try.....
The D1 uses a delta/sigma design (from the 'old' Crystal Semiconductors school). This type of design is a bit less susceptible to jitter than an R-2R DAC (like the famous TDA1541 and PCM1704).
But more important is the SPDIF receiver chip in this case. Thats the place where the actual clock is being recovered from the digital input signal. The D1 is not particularly good at this job (not really bad either). Not sure what chip is being used, but likely its something like the CS8416.
Main issue in your case is that the output of the Airport is quite jittery. Comparing it to the USB input is not particularly useful. This is not the strongest point of the D1...... More telling would be a comparison with the digital output of a decent CD player.
To improve your signal chain when using the Airport you either need a DAC with an excellent jitter rejection or something like an X2 or the Audio GD DI to straighten-up the digital signal.
The strongest points of the D1 are its analog stages, the versatility (DAC/PreAmp/HeadAmp) and flexibility (Tube AND OpAmp rolling).
But, to be frank, there are no DACs in the sub-$200 range that do a better job in terms of jitter handling. The nearest option price-wise that does an excellent job in terms of jitter rejection is the Audio-GD NFB-11 ($280).
Not sure if I actually dumbed-it-down or made things even more complicated
Some straight advice: if you want to use the D1 with an Airport I would advise you to invest in something like an X2.
Confused Reclock with Upsample, but upsampling rejects jitters. A good transport will give you the audio spectrum 44.1khz-96khz though. USB on the D1 is not goood
SPOT ON middachten! - Now I get it
Regards your advice - do you know of something like the X2 that would be worth looking in to?
I'd be happy to try the X2 but the Airport Express (although it has a USB port) only outputs through optical.
Thanks for the info though! Just what I was after - and more importantly at a dumbed-down enough level
Hi Ninjidiran, What do you mean the USB is not good. I am really not good at all this terminalogy. I thought the only way to get the signal out of my computer was to use the USB. Is there a better way?
Spdif on the mav is the best connection, the optical pops on some optical sources and the USB receiver is not high grade.
The D2 should be using the Tenor chip which is quite a bit better.