Saturday, 25 February 2012

QA350 and O2

Had a chance to connect up the O2 with the QA350. Having spent two or three sessions with the QA350, it has proven to be a very useful addition. From this, I can now take my own music and use to demo new equipment. For example, been planning on trying out the V200 with my EM4, and now, with the QA350, I can in someway have a more 'controlled' test setup - rather than using the vendor's setup. Secondly, this unit; whilst compact and light weight, is not really body wearable. Even with a jacket or suit, the size is just too large. With a bag, there is not a problem. But issues arise when you are walking around, with a delicate and shortish headphone lead, not the safest approach.

The volume control on both the QA350 and the O2 needs to be no more than a 10 degree rotation from their 'zero' position before the volume gets too loud. Not a good arrangement. I will have to find someway or padding the output volume down, or reducing the gain. This is why the V200 would be a good option, as there are DIP switches on the back to adjust pre-gain. Mated with their V800; which also has output gain selection, could tailor a solution where the EM4 can be used at sensible volume control positions - of which I deem as around 40%-60% of full rotation.

Currently listening to HD Track's 1812 Overture, downloaded as 176.4/24 converted to WAV via XLD, and then down samples by Sample Manager (using isotope Resampler set at 'High' and MBIT+ dithering) to 44.1/16. Just finished it on the O2, and to me, the sound was a little confined, in my head, and potentially a little flat. Having started with the QA350, I can't tell that much difference from first impressions. On a side note, both the O2 and the QA350 have had relatively little burning in time; probably at most 10 hours each. Whereas my EM4 have now got a very healthy 200 plus hours. The volume control on the QA350 has channel imbalance at low levels, important for me cause the EM4 are very listenable at those levels. Also the optical output light is always on, so there is a constant red dot on the main side panel. When the charger is working, I can detect a high pitched noise. Owning to the warnings about Lithium polymer batteries, I am keeping a close watch on them.

Back to the QA350. I dare to say, that with this very casual session, there isn't a lot between them. I think I could hear a few more details with the O2 then with the QA350; and the cannons were more powerful with the O2. In some way, you could feel the cannons - not the full body sensation, but just around the ears, if that makes sense... Both the sound stage is limited to between the ears. I know the EM4 can project sound around the ears (for me anyway).

Now moving onto the Computer setup. This time, O2 front end, from the Calyx, running Fidelia with the full resolution FLAC file. Immediately, the clarity returns! Soundstage is wider - straight away! The setup in Fidelia - 24 bit MBIT+ dither, device sample rate set tup 96kHz with isotope resampler set at 'High'. At this stage, I am running the volume at 100% on Fidelia and using the O2 to control. Changing Fidelia to point at '9 o'clock', has shifted the O2 to be pointing at '10 o'clock'. Differences in sound? A little loss in clarity, but very minor. With dither turned off, and the Fidelia set to 9, I could hear a difference, or missing music, that was there before, when dither is on. Overall, the presentation on this setup is more musical than through the QA350. Oh yeah, the cannons on this were way more body, substance and 'cannon-like'. Night and day. Through the QA350, they just sounded like pop guns, or cannons in the far distance.

The last test is to play the same 44.1/16 WAV file on the QA350 through Fidelia. Oh yeah, the file size is 524.4 Mb compared with 150.9 Mb. Interesting in that the jump from 176.4/24 to 44.1/16 should be a 6 times reduction in information. So, given FLAC has some compression, the full size 176.4 file should, by rights be 905.5 Mb, therefore, the FLAC file has losslessly reduced this by around 40%. But this comparison with the higher res file is moot - the Calyx is limited at 96kHz.

Firstly, the sound stage, again, much wider. The rendering of the music, is more lively and more musical than the QA350. There is a loss in clarity between the higher res file and the lower res. A little more separation in the music and instruments. It is, 'more focused' in photographic terms. But the difference between the QA350 and Fidelia is quite noticeable. I would vote Fidelia in this instance, based on this one track. Again, the cannons on this war much more powerful with more body and substance.

Finally, the same 44.1/16 WAV track through iTunes. Smaller soundstage - less clarity and detail. Very similar to the QA350. If anything, it sounds a little more confused, or muddy, than with Fidelia. What it does sound like, compared with Fidelia, is that there is a limit to the music, in both sound stage, dynamics and clarity. Fidelia sounds like these restraints have been removed. Turning up the volume does not restore, or give iTunes the same energy as it does on Fidelia. The canons are definitely more like the QA350.

After this track, Adele's 'Daydreamer' came up quickly, and it sounds pretty good on iTunes. The guitar strumming and her vocals, focused and articulate. Moving quickly to Fidelia with up sampling to 96kHz, improvements in the sound; but the extent mot as great as that with the 1812 Overture.

Now, what does this short hour session tell me;

  • I can hear differences between the same track (source at 176.4/24) played between 44.1/16 and 96/24.
  • Dithering on Fidelia is required when using it as the volume control.
  • The headphone amp sections on the O2 and the QA350 is in principle very similar - but sure to be differences that can be told over a longer, more rigorous session. 
  • There wasn't a huge difference between playing from the SD card and the computer. Perhaps this whole jitter issue, etc, is the storm in a tea-cup? 
  • The soundstage, clarity and body is much better on my Fidelia setup than the QA350. 
  • QA350 hasn't been burned in. 
  • Cannon love on 44.1/16; best Fidelia, then by a long margin iTunes, and close behind that QA350. 
What I cannot conclude;
  • QA350 sounds inferior to the computer. Using different files and sampling is surely more of a difference.
  • That my opinions or observations can be repeated. This is not a double blind A/B. This is me on a quite afternoon listening to the same track on 5 different setups. Not switching back and forth between each one. Each one in its entirety and in full, followed by the next. So take the above with a grain of salt. Also, this was done with one track, a classical track. At the end of the day, YMMV, and so will mine, from day to day.

Wednesday, 22 February 2012

QLS QA350 Mod V2

Just purchased the QLS Mod V2 - to try out some decent portable audio in contrast (and comparison) to my iPhone 4. The first thing I noted was the supplied SD Card (A Sandisk Class 2 2 GB card) did not work with the player. I had to use my Class 10 Sandisk - this works fine. At the same time, I have also tried to convert my files into WAV. For this, I am currently using XLD to convert to WAV format, and then Audiofile's Sample Manager to down-sample to 44.1 kHz and 16 bit. A little bit convoluted, but still, it works.

At the moment, the first track, after 0 hours burning in was Holst's Mars from HD Tracks. I have only had a very brief time with this, and a few quick notes when listening to a more familiar CD, Coldplay's X&Y. The interface is refreshingly simple. Some say too simple, but I think its a great minimalist approach. I have no issues with that. It is quite a nice departure from a full blown computer playback - absolutely no frills.

When I am listening to music, I am not too concerned about the CD cover, track name, etc. I just want the music. So far, there isn't much hiss or noise when using the EM4. Which is a good sign. Increasingly, I am of the feeling that at 59R the EM4 aren't as susceptible to noise as I thought that they would be. Which is a good thing, but also, I am of the feeling that they probably need more voltage to drive well, as opposed to being current hungry. So perhaps they can be seen more like my HD650 in terms of amplification.

Anyway, back to the QA350. With the Mod V2, this had apparently an upgraded headphone section; using AD8397 as the driver. I must say, that at this stage, the sound is quite enjoyable and articulate. Nothing overly wrong, or excessive at all. The bass is probably a little loose, but the mids and highs quite well defined and controlled. It lacks a little bit of life and energy, especially on complex parts, it feels like it is losing some control over the music. But in simple guitar passages - quite lovely. Bear in mind, this unit has had zero play time thus far; so all comments need to be seen in this light.

Doing a quick comparison with the D-Zero over one track - 'Hardest Part'. The sound is a little more lively and wider on the QA350. The bass is more 'focused' and a little softer in the mix than with the QA350. This was played back through Fidelia, with volume control all the way up, and volume controlled from the D-zero. The vocals on the D-zero has a slightly duller and small image. The music in general was more lively than the QA350. In very short, brief and un-critical manner, the QA350 had a more musical balance, that already feels more enjoyable. But then, the problem (?), maybe there are just so many variables with computer playback, that it's hard to figure out just WHAT is the source of the negatives and positives.

Sunday, 19 February 2012

Calyx Coffee - The Inside Story

On a roll, here are the innards of the Calyx Coffee. It appears from my causal observation that the headphone output is not driven by its own amp circuit, and is paralleled with the RCA outputs; which I presume is coupled by the Fine Gold caps directly to the ESS9023's output.

  1. ESS9023P - DAC
  2. Tenor TE7022L - USB Receiver
  3. SC12.000 A1026 12 MHz clock
  4. LD1117A - Adjustable regulator
  5. Atmel ATMH038 - Some sort of Microprocessor to control the buttons
  6. Nichicon Fine Gold 220uF/35V (x2)

Saturday, 18 February 2012

iBasso D-Zero - The Inside Story

Finally (!) had the chance to open up the iBasso D-Zero and have a peek on the inside. Enjoy. Some of the major components;

  1. WM8740SEDS - DAC Chipset.
  2. AD8656 - Dual CMOS Amplifier
  3. PCM2706 - USB Receiver
  4. HEF4011BT - Input NAND Gate
  5. NEC UD2-4 - Relay
  6. Nichicon FW(M) 470uF 16V (x4) and 100uF 10V (x2) Capacitors
  7. KDS 12.000 MHz Clock of some sort.

Wednesday, 15 February 2012

Great link - The complete DAC D/A converter list, showing various DAC and digital players and their chipsets.

Hi Res Music

I just purchased a few more albums from HD Tracks, so in total I now have seven HD albums;

  1. REM - Out of Time 96/24
  2. Nirvana - Nevermind 96/24
  3. Janos Starker - Cello Suites 176/24
  4. Janos Starker - Cello Concertos 176/24
  5. Holst - Planets Chesky 96/24
  6. Diana Krall - Quiet Nights 96/24
  7. Charles Mingus - The Black Saint and the Sinner 96/24

What I really wanted to try out are the higher resolution of 176 (which is 4 times 44.1 or CD format) files. At the moment, my DAC tops out at 96 kHz, so some software downsampling will be required, I will get them to play at 88.2 kHz. The next step is now to look for a DAC that can play these files, it seems, up to 176/192 kHz.

The short list so far;

  1. Metrum Octave (can't do 192)
  2. Violectric V800
  3. Mytek DSD-DAC Preamp (can also do DSD)
  4. Bel Cano DAC3.5VB
  5. Weiss DAC202
  6. Weiss DAC2
  7. Musical Fidelity M1 DAC
  8. Aqvox USB-DAC
  9. Junilabs Jundac Two
  10. Anedio D2

The option exists for a dedicated computer to DAC interface and a separate headphone amp.

Tuesday, 14 February 2012

Some DAC Thoughts

Looking at the 'Stereophile' reviews and measurements for some DACs, and it looks pretty interesting. John Atkinson notes that the Weiss DAC202 is the best DAC he has yet to measure. To use that as the 'benchmark', I then compared this superficially to three other DACs, Bel Canto e.One DAC35vb, Musical Fidelity M1-DAC and Musical Hall PH25.2.

An interesting aspect is how close the Bel Canto and M1 comes to the 202's performance. The 50Hz sine wave spectrum for the Bel Canto looks really nice, with a nice decaying set of harmonics, with each higher harmonic less than the previous. But seems to be some weird left and right channel mis-match. But the best looking one would be the Musical Hall, with only a slight peaking on the 5th harmonic. Perhaps this is due to the tube output stage?

Secondly, the graphs on the jitter also presented some interesting issues. The Music Hall has a lot higher noise floor at around -125dB, but shows a relatively tight base, especially with over-sampling, and no side bands. Whereas all the other DAC had side banding at 16 bit, but none with 24 bit. The Weiss floor hovers below -145dB, whilst the Bel Canto just below 135dB and the Music Fidelity at -145dB.

What this very cursory and laymen's review of these measured performance is that the $550 Music Hall and Music Fidelity $750, compares very well to the $3,500 Bel Canto and the $6,500 Weiss. And it also seems that when the lesser ones are paired with a good digital input (that has itself good performance in terms of jitter, noise, etc) the DAC can perform at very high levels.

Saturday, 11 February 2012


After researching through some DAC, I have come to realise that my gut says the segmented R-2R 24 bit 96 kHz DAC PCM1704U-K could be the right direction for me. The following is a short list of DAC, either in kit or complete form, that uses the PCM1704 DAC Chip.

This list will continue… More will follow.

Monday, 6 February 2012

O2 Amp and the EM4

I finally (!) got around to purchasing a 3.5mm to RCA cable so that I can now connect the Calyx Coffee to the O2 amp from JDS Labs. Also of note, was the trial installation of Amarra Mini. Last night and right now, I am listening to music stored on an external firewire drive connected to my Macbook Pro. The music is running through iTunes/Amarra and the out to the Calyx and then O2, finally to the EM4. Currently listening to Adele '19'. Last night, I did a quick A/B between 16/44 and 24/96 on REM's 'Losing My Religion', as well as some casual listening with my favourite tracks.

Back to Adele, the first track, I can only describe the guitars as one of the most realistic I have heard through my headphones before. The articulation and intonation of the guitar, along with the strumming and 'shimmer' sounds very real. Having limited experience with both orchestral performance and guitar/drum band gives me some basic insight into how things sound when played live.

From this, and with the current setup, I can say that the bass and guitars have a very clear definition and sound to it. Comparing this to the other tracks, I can say two things about guitars and the EM4s. Acoustic guitar sounds phenomenal; warm, crisp and articulate. Bass guitar sounds just like on stage through - compared to my own bass playing experience. Mind you, this O2 has NO burning it and hasn't had its battery charged since it was delivered. Again, due to my laziness, I have not yet got an AC adaptor...

Again, with the current setup, I am convinced that the headphones (and by this assumption, speakers) play the largest part in the tone and sound signature of the music. Having dabbled very briefly into 24/96, I can say that, the resolution has the next most important effect. I am not not 100% sure of how and to what extent the Transport, DAC and Amp affects the music. But I can say that through the iPhone and this current setup, there are differences. But surely not as much as changing headphones. If I had to break it down, I would say that for now it'd be 50% headphones, 25% source and 25% transport/DAC/Amp. Perhaps this will change over time, but it will need far more exploration.

Well, the next few tasks are to decide between Audirvana and Amarra; and then find the right DAC setup.

A few quick thoughts regarding the DAC setup, after long thought, I am really looking for a compact solution that is airline luggage suitable. That rules out 19" wide units, and really limits this to one or two boxes that are at least half rack width. Not knowing how much travel is installed for the future, I would like to have a relatively portable system. Perhaps an A and B system, where A is the more permanent one, and the B is the one that I can take on short trips. As much as possible, I would like to share components, as I am trying hard to simplify my setup. So thinking more and more, the Halide Bridge or DAC HD makes so much sense, it removes cables and power supplies. It just makes sense. But the question really is going to be, will they deliver an improvement and get me closer to the music and quicker to relaxation. The search continues.

Wednesday, 1 February 2012

DAC and EM4 Progress

Currently listening to Norah Jones'Come Away with Me on the iPhone and all I can say us that the sound is warm, effortless and intimate.What more can I say about it? The other night I was walking home and listening to Muse's Resistance and let's just say that the hairs in the back of my neck was tingling. Amazing.

My search now turns back to a suitable DAC. The long term goal us to have a computer based system with a DAC and headphone amplifier. Nothing special. The quest to search for the right DAC had led me to a few thoughts. Firstly computer technology changes faster then audio. In the sense that DAC technology moves relatively slowly. Bit USB or firewire changes much faster. And on that vein I have decided to separate the computer souse to the audio side so to speak. That is to get a USB or firewire to SPDIF or other interface without a DAC separate. This results in two points, one more box and the ability to greatly choose the best suited DAC available. One possibility is that I can then use the twisted pear audio buffalo, which is sitting waiting to be put together. Another alternative its to get a DAC that has digital output as well which allows me to choose which to use.

In the initial search for a computer to digital audio interface, leads to a few very standard offerings. M2Tech, SoTM, Lindemann, Halide, Wyred4sound, Audiophileo, Musical Fidelity, Berkeley Audio, and others. However the choice of this CDI is somewhat dependent on the choice of the DAC itself due to the interface type it can accept. For example the halide and Evo had only a single output, coax it RCA. Whereas the V-DAC has more. But at this point the most relevant question is whether or not I ever want to use DSD format. But that is almost another topic unto itself. So for the moment I will continue to enjoy the music whilst the search continues.