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[#21] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 if u have diyaudio account, you can see this document http://www.diyaudio.com/forums/attachment.php?attachmentid=159883 True Dual Mono setup require 2x Buffalo + 2x IVY + 2x Placid + 2x Placid BP = (289+139) x 2 = $856, not including 4 transformer for 4 PSU, really worth? and not talk about larger case for extra board. But the flexibility of DIY kit is you can add anytime if you like. |
hercules 正式會員 112.xxx.xxx.224 |
2010-06-29 23:32 | |
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[#22] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 i am talking about some basic principles about dac design . briam and russ reply not explain the issue. recommend you to read good engineering book like analog device data conversion handbook |
batmanames04 正式會員 114.xxx.xxx.255 |
2010-06-29 23:35 |
[#23] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 I'm talking about THD -108 vs -120db in v out and i out mode, not stacking dac or dual mono issue. |
hercules 正式會員 112.xxx.xxx.224 |
2010-06-29 23:45 |
[#24] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 I said it's not going to improve and not so feasible if you want to enjoy it's reclocking. from ess paper The SPDIF interface is more complex than the DSD and I2S since it must first derive the embedded clock in the bi-phase encoded data. In fact, experience with many forms of SPDIF decoder suggest that most fail in the presence of high jitter due to the lack of robustness in the clock recovery process. To avoid this potential problem the Sabre SPDIF interface avoids having to extract the clock at all: decoding is done using a method that does not require an explicit measure of the clock frequency. Specifically, the digital input6 is first corrected for 5 The DSP engine of the Sabre™ DAC operates at either 27MHz for audio rates up to 96KS/s or 40Mhz for audio data rates up to 192KS/s. Neither of these rates is integer-related to the audio clock. 6 The SPDIF input is a conventional CMOS input pin – it is not a comparator – the user must provide a comparator prior to the input pin if it is needed. Technical Details of the Sabre Audio DAC Martin Mallinson and Dustin Forman, ESS Technology Technical Staff T SABRE DAC INTERNAL OPERATIONS 2 50% duty cycle by means of a discrete digital delay line that is able to delay either the positive edge or the negative edge of the signal such that after this delay line the signal is at 50% duty cycle. Thereafter an assessment is made of the width of each pulse based on its relation to recently seen pulse widths and a decision circuit assigns each a width of 1, 2, or 3 units. A state machine then operates on the assigned widths in succession; this state machine is searching for the block boundaries and the bit states. The state machine makes no attempt to re-time or otherwise decode the clock – it simply “time stamps” the event and passes it to the downstream processor. Using this method the SPDIF interface is able to accommodate 50nS of random jitter and 200nS7 of sinusoidal jitter in the incoming data. B. Rendering the Data into the DAC clock domain The I2S and DSD are clocked data streams, they do not require the method used by the SPDIF interface, but they result in the same thing: similar to the output of the SPDIF decoder, at a certain asynchronous time, they present to the downstream processor the new bit or word from the interface. Rather than trying to lock a PLL to the data rate of this interface signal, the Sabre DSP uses the arrival time of the data as a gating signal for the first part of the processing. Specifically, we now need to apply a filter to the digital data – we must remove the image that will be created when we upsample the data to our much higher clock rate. This filter involves a number of cycles of the DSP. One desirable consequence of this method is that the over-sampling filter time constant tracks the data rate. The data we have after this process is, of course, mathematically correct, but if we use this data in the higher clock domain we will have a great deal of noise, since as soon as we try to sample the data we must decide at which edge of our high speed clock this data is to be used. That choice is never correct – this sample delivered from the interface is supposed to be at some point between our high speed clock edges. The problem then is this: we have the data stripped off the transport medium – the data is mathematically correct but we don’t know where in time this data is supposed to be, and even if we did we cannot snap it to our high speed clock because that represents a quantization in time and hence noise. The conventional solution is well known: first a digital PLL is used to remove the jitter of the incoming data (since it will suffer from jitter in the transport clock) and then a polyphase filter is employed to rate-convert the signal8 into the new clock domain. These kinds of sample rate converters work well but they are limited to certain ranges of operation (they have a limited ratio of rate conversion – typically about 8:1) and a DNR less than that in the digital data itself. The Sabre DAC rate converter has two advantages compared to the poly-phase filter approach and is described in great detail in the pending patent. Firstly the rate conversion is unlimited – allowing the Sabre to always achieve a conversion into its 7 200nS is even greater than the nominal SPDIF clock period – but nevertheless the SPDIF interface correctly decodes the data stream if its FM modulation is at a sufficiently low frequency. 8 For an introduction to this technique see the Analog Devices AD1896. |
batmanames04 正式會員 114.xxx.xxx.255 |
2010-06-29 23:45 |
[#25] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 but i have to correct, buffalo can set to left board and right board, feeding same spdif stream, the board will recover L data from spdif for left board, R data for right board, no external transciver or receiver required. |
hercules 正式會員 112.xxx.xxx.224 |
2010-06-29 23:49 |
[#26] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 that's why i said ess chip is not traditional DAC due to it's highly complex and integrated reclocking and dejittering architecture when compared with high-end chip offered by BB, AD and Wolfson. If you feeding the ESS with I2S signal, with MCLK recovered from External SPDIF receiver, NONE of the PLL reclocking features will be employed as the ESS paper stated. 最後修改時間: 2010-06-29 23:56:01 |
hercules 正式會員 112.xxx.xxx.224 |
2010-06-29 23:53 |
[#27] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 thanks please let me know the performance of buffalo vs w4s vs sim vs dac202 in future i think moon and mcintosh should be the best, the others are quite similar in performance |
batmanames04 正式會員 114.xxx.xxx.255 |
2010-06-29 23:57 |
[#28] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 For Dual mono: http://www.twistedpearaudio.com/forum/default.aspx?g=posts&t=1025 Hi Nic, there is a very real benefit. What happens is that the Bal/SE stages are really now just halves of a differential signal. You still get all that normal benefits that each fully symmetrical half would normally have. :) The key here is the fact that the I/V stages combine to increase the dynamic range. Also the outputs load the two halves of the DAC with the same signal, but in exactly the opposite phase. This further increases dynamic range and increases channel separation. So while, yes, its a lot of parts in there, it does indeed make things better. :) Cheers! Russ I think the Dynamic Range high enough for a 32-bit chip, as we have 90% chance playing 16/44 recording, 9.9% of 24-bit (144dB DNR, already over 120dB threshold of pain for human) and very few chance to have 32-bit recording. and I don't have speaker (even headphone) and quiet listening room to accommodate the dynamic range of over 100dB playback in my poor home. So the real benefit is channel separation, I think. |
hercules 正式會員 112.xxx.xxx.224 |
2010-06-30 00:08 |
[#29] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 For dual mono, It's using 4 DAC (1/2 of ESS9018) parallelly for each phase, that's 4 for L+, 4 for L-, 4 for R+, 4 for R-, but I'm going to use Single End only, not balance out, it's not so beneficial in my case. MCD500 also using single ESS 9008 chip (4+4) for stereo http://www.mcintoshlabs.com/products/1219.asp • Quad Balanced Digital to Analog Converter The 8 channel 24-bit, 192kHz Digital to Analog Converter is used in a Stereo Quad Balanced mode. All levels of music are reproduced with a wide dynamic range and extremely low distortion. 最後修改時間: 2010-06-30 00:35:40 |
hercules 正式會員 112.xxx.xxx.224 |
2010-06-30 00:22 |
[#30] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 suspect dac202 using 2 single chips as some measurement data showing 125db 0.000056% and also some c hing mention the other side of pwb with another 9018 |
batmanames04 正式會員 114.xxx.xxx.39 |
2010-06-30 01:20 |
[#31] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 ES9008Sの8chをモノラルモードで使用して、LchとRch用に2個使用した場合には134dB以上のDNRを得ることが出来ます、と書きましたが、S/PDIFデコーダー内蔵DACを単純に2個並べて、各々のS/PDIF端子にデジタル信号を入力させればDIR回路のロックイン・タイミングが一致して左右DACのアナログ信号位相が合致するのか?問い合わせていますが、まだ回答はありません。小生は15年前に、DIRにYM3623Bを用いたDACユニットを2台並列動作させてみたのですが、この場合はその時々でロックイン・タイミングがバラバラで左右DACのアナログ信号位相が回転しまう、という経験がありました。この現象をオシロで確認する前は、「音の良い(左右位相が比較的揃った状態)時と、ヘンテコリンな音の時がある・・・・」不思議でした。 たまたまポータブルDSOを持っていたので波形を確認したところ、一同、口をアングリ状態でした。しかし当時、CS8412を用いたDACを2台並べて同様の並列動作をさせてみたところ、この場合にはロックイン・タイミングが毎回合致し、左右DACのアナログ信号位相は揃っているのを確認していました。 問い合わせ後、日にちが経っても返事が無いので自分で確認することにしました。 DAC評価基板をもう一枚借用して検証してみました。 |
batmanames04 正式會員 114.xxx.xxx.66 |
2010-06-30 18:42 |
[#32] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 spdif driving 2 ess reference board |
batmanames04 正式會員 114.xxx.xxx.66 |
2010-06-30 18:46 |
[#33] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 Left and right channels O.K |
batmanames04 正式會員 114.xxx.xxx.66 |
2010-06-30 18:49 |
[#34] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 ess |
batmanames04 正式會員 114.xxx.xxx.217 |
2010-07-01 02:02 |
[#35] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 found a review http://www.odysseyaudiohk.com/cgi-bin/yabb/YaBB.pl?num=1278154729/5#5 |
batmanames04 正式會員 114.xxx.xxx.123 |
2010-07-04 16:06 |
[#36] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 moon 750d review http://www.techradar.com/reviews/audio-visual/hi-fi-and-audio/cd-players-and-recorders/moon-750d-673709/review?src=rss&attr=all |
batmanames04 正式會員 114.xxx.xxx.17 |
2010-07-07 12:56 |
[#37] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 moon 750d http://www.ultraaudio.com/twbas/twbas_20100601.htm |
batmanames04 正式會員 114.xxx.xxx.17 |
2010-07-07 13:21 |
[#38] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 http://www.my-hiend.com/leoyeh/2010b/20100613a.pdf |
batmanames04 正式會員 114.xxx.xxx.17 |
2010-07-07 13:21 |
[#39] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 quoted from sim audio s president 預測Ethernet將成數位音樂傳輸的主流 750D最吸引人的賣點當然是完善的數位輸入,包括USB、Ethernet都整合在內,但Jean最後強調,他認為USB並不是未來最終的解決方案,而是這一兩年比較方便和流行的界面。Jean建議音響迷如果要用電腦當作數位訊源,最好搭配比較高階的音效卡,選擇S/PDIF輸出,效果一定比USB更好。至於未來數位傳輸的主流呢?Jean大膽地說,未來一定是Ethernet的天下,不僅可以整合家庭所有數位音源,同時也可以支援網路遠端操作,不在家裡也可以聆聽自家音樂資料庫。但無論未來數位訊源如何演變,Jean說只有750D預先為所有音響迷準備好了,而且是不折不扣的Hi End產品。與Jean Paulin一席談,我們似乎預見了數位音源未來發展的真知灼見。 |
batmanames04 正式會員 114.xxx.xxx.211 |
2010-07-07 14:03 |
[#40] moon750d vs wyred4sound dac2 vs dac202 vs mcd500 yes, ethernet is the best, both in terms of convenience (no need to have a computer nearby) and for control of jitter. BUT the problem for a hifi manufacturer is that it has to write it own software for playback and networking interfacing. This is beyond the expertise of 99% of them. You can't just open itune or cplay and hit play with such ethernet devices. |
mahi 正式會員 219.xxx.xxx.137 |
2010-07-07 14:15 |