The Bitstream Chip
The star here is the TDA1305T. It was once a popular core IC in many famous DACs and CD-Players, to name a few, Cambridge Audio CD6, Cyrus dAD3, NAIM CD5, Rotel RCD-975. Those are legendary good sounding machines.
In a way, it must be the DAC that contributed (at least partially) to the good sounding result. Technically the specification of DAC chip is nothing fantastic compared to the latest chip like the Burr-Brown PCM179x series, or the Analogue Device’s latest DAC chips. It is using fairly outdated Bitstream conversion technology; check that out on Google for more information. However, many audio freak claims that this earlier CD technology is in fact producing more analogue and better sound compares to many latest DACs. For this, the Bitstream Philips TDA1541 has become a legend and one of the most raved DAC among HiFiers worldwide. Why a decades old product can sound so good? Many discussions have been going on in forum. I shall leave that to the experts.
The DAC Design and implementation
The USB signal is converted by the Burr-Brown PCM2902 and fed into the receiver chip through a buffer chip to reduce signal losses. The coaxial and optical inputs are fed into the receiver chip in the same way. The Crystal CS8414 is a very common receiver chip in many DACs which is able to decode digital signal up to 92kHz. There is nothing really innovative in this design, but there is something to take note, there are no output opamps because they are already built-in, the output is just simply coupled by few kinds of capacitors.
Test Equipments
Entry-level Speakers Set-up: KEF Q15.2 Bookshelf Speakers, NAD C320 Integrated Amplifier, NAD C541 CD player, Atlas Compass Digital Cable
Overall the DAC sounds better than direct analogue output from the C541. I shall not elaborate more on this, as I only listened briefly to this set up when I was back home in Malaysia for a while. That is my room set-up.
Earphones: Direct driving modded Xbrand with 100ohm resistor, laptop running vista and Foobar2k.
I spent most of the time using the modded xbrand to test out this unit. The direct output from this DAC is loud, damn loud, and I have to add 100ohm resistors to the earphones to tame down the loudness. The volume control could be done from the computer but NOT advisable as the volume is too loud even set at low level. Basically you need a headphone amp to work with this
The Sound
(The following tested using modded xbrand)
When first power up, there is nothing special about the sound, just normal, it could not compare to any of the other 2 DAC I reviewed, the Mini USB DAC and the NG27. I got disappointed and just gave it to my roommate to drive his PC speakers. The unit somehow left turn on till the next day when I saw the power light still on. It feels warm, so I plug in my xbrand to test whether it is ok.
Amazingly, it is not just OK, it is as if a total make over, the sound is smooth, very smooth, especially the highs, expansive soundstage, loose bass (tubey kind), and more importantly, neutral sounding in my opinion, the lows, mids, and highs just blend so well that none of them is overwhelming each other. I sat in front of the desk and having audio orgasm the whole morning.
I only heard of such sound signature when I was younger, when my dad was playing CD using LD player (bitstream?). I know it is weird, but it just reminded me of that.
I decided test out using different kind of music and format to check out the performance, there are few things I want to highlight here:
It can cure bad recordings by smoothing out the edginess or sharpness that irritates the ear. I don’t know how the DAC achieve this, but it is simply amazing. I have some badly recorded MP3s; playing them using Mini USB DAC is just making my ear bleeds. The revealing nature of the Mini produces some high pitch sound whenever there is not enough data in the MP3 to be converted in waveforms. The bitstream DAC is different, when there is not enough data in the MP3, it just somehow smoothen and roll off the waveform to generate some kind of smooth wave (just my guess, haha). The end result is it really makes bad recordings and low bitrate MP3 alive.
The expansive soundstage. In my own explanation, it is like dragging and expanding the original music to produce a kind of airiness, wide soundstage. Sometimes it feels a little bit artificial and weird, but I simply love it, it makes music listening much less tiring (using earphones). Listening to new age music is particularly enjoyable due to the soundstage.
I call it transparent; some call it bass-shy? The bass and mids are much less colored compared to the NG27. The bass is just adequate but and slamming, go deep and loose, sound like tube kind of bass in my opinion. The mids are sweet, a little bit too sweet for female vocal and string instruments. It is different from some kind of outstanding mids which the lows and highs are recessed just to make the mids stand out. In this case, the blend is good.
I believe this DAC is not something for everyone as it has its own character. It doesn’t excel in bass and detail which many consumers are looking for. It takes about 20 to 30 min to warm up, and you need an amp to drive your headphones.
However, if you are like me, who likes the sound I mentioned above, then it is a good DAC for you. Let me make a clearer comparison, NG27 is like Senn HD600, and the TDA1305 is like the AKG K501. Both serve different master.
Of all 3 DACs I reviewed so far, I like this most. Although it is the cheapest among all, just slightly over RM200, but I don’t think it sound cheap at all. Now it stays in my primary set up…hahahaha…
original post:
http://isnoopyu.com/tda1305-dac-review/
