ODAC IMPRESSIONS
I am giving an initial impression of the audio performance of the ODAC and comparing it with the other gear I have. The technical aspects and measurements are already on the designers blog.
NwAvGuy: ODAC Released
https://hifiduino.wordpress.com/2012/04/18/odac-revealed/
EQUIPMENT:
Source: Dell L502X USB3.0 Ports
USB Cable: FiiO USB Cable with two ferrite cores at either ends.
Source Material: FLAC / ALAC / 320kbps mp3
Amplifiers: FiiO E9, FiiO E7, DIY Beyerdynamic A1 Clone, Embedded Hybrid Headphone Amplifier (EHHA) BJT Version. (Will check with my FiiO E11 later).
DAC: ODAC, Quad Wolfson 8740 DAC (donated by a fellow forum member), FiiO E7 (Single Wolfson 8740), DIY Burr Brown 1798 DAC, Hifiman HM601 Philips NOS DAC.
Headphones: Sennheiser HD650
Test Albums: Eagles Hotel California, Drooling Dalton, Shania Twain, MJ Billie Jean, Santana, Madonna (Frozen), George Micheal, Piya Basanti by Ustad Sultan Khan (Great bass lines), Rehman (Tracks from Roja, Bombay, Rang De Basanti), Gazals by Jagjit Singh & Mehdi Hassan etc....
ODAC:
First Impression. A very small PCB with two ICs, one being the tenor TE7022 USB interface chip and other the Sabre ES9023 DAC chip with all parts being SMD. Installed it in the FiiO E11 packaging case with still room to store the E11. No windows drivers required. Windows performs a quick check and loads the drivers and the device is recognised as ODAC. Can be connected to ipad using powered USB and camera connection kit and not directly as it derived power from the USB.
Dead Silent as expected (however all the DAC are dead silent except for some noise in the E7 around the audibility threshold). there is no audible evidence of any jitter.
24 bit Adaptive Interface. Software volume control becomes viable without loss of detail.
I prefer tight and textured bass, with the right amount of kick. On the other hand I hate treble with even a slightest bit of harshness as I find it highly fatiguing. The best part of the ODAC is it extends the high frequency spectrum without any harsh treble thereby giving a very detailed presentation (very prominent in the Hamma track from Bombay).
The midrange is very forward sounding, detailed and revealing. One can hear when the singer inhales between lines (especially prominent with some tracks by Jagjit Singh). The guitar riffs from Eagles tracks materialized in front of you with space between the various instruments unlike the low end muddied presentation of some devices that I have heard.
This detail and resolution has some caveats. Poor quality tracks (either heavily compressed or badly mastered) are unbearable to hear even on my HD650s (which is known to be forgiving). This leads to fatigue over prolonged listening sessions especially with less forgiving or treble happy headphones (As a protective mechanism in the human ear the stapedius muscle becomes taut listening to impactful bass decreasing the sensitivity to bass frequencies while higher frequencies lead to ear and headaches, so keep the volume level in check and take frequent breaks). On the other hand the HM601 retains the midrange quality however makes even 128kpbs rips sound decent (courtesy its NOS DAC and a high end roll off).
The transparent presentation helped me in distinguishing the sound signature of my amplifiers with the EHHA and E9 having a flat frequency response and the slight coloration (bass enhancement) of my DIY Beyerdynamic A1 clone due to its high output impedance (though I like its visceral effects on kick drums).
Comparisons:
The ODAC is audibly better than the FiiO E7. Its tonality is similar to the DIY burr brown DAC however its extracts more detail. When compared to the quad Wolfson 8740 the ODAC performs better in the bass and treble region however the midrange is smoother in the former.
The problem is not with the chip itself but its implementation. At the same time the Operational amplifier introduce a sound signature of their own. This may be beneficial to those who are into DIY and try opamp rolling to tailor the sound signature to their preference according to their headphone capabilities.
Final words: Great performance for the price. An ideal external sound card. Though I think the $50 custom enclosure by JDS labs is a rip off. Make your own enclosures. DIY cooking is better.
Future objective audio devices that I am interested in.
I am interested in the "Wire" headphone amplifier. If people are interested some from the forum may try with getting PCBs made from PCB power for a group buy. Here is the link:
"The Wire" Ultra-High Performance Headphone Amplifier - PCB's - diyAudio
