I must also preface my post by stating that I was not really sure where the D7 would fit into the extensive line of portable devices produced by iBasso; It seemed at first glance as though it might be in competition with the D6 or D12, but after examining it in detail and listening to it, my thinking has changed.
Not only is it a very high-quality DAC, sounding as good, if not better, out of the box than my desktop DAC. It is also in its own right, a superb headphone amplifier. Size-wise, it is the same length as the D6 but about 1/8" thinner and very slightly wider. Because of the reduced thickness, it appears to be smaller than the actual dimensions.
Packaging is similar to that of the other iBasso products. Included with the D7 were 2 USB cables of differing lengths, a leather carry case, rubber feet and an extra set of panel screws, although there is no necessity to ever open the case.
The first challenge was to see if the D7 would be recognized by my Linux OS, as some previous DAC's by other manufacturers were not. I was pleased to find that the D7 was immediately recognized, showing as "XMOS Audio USB 2".
There are several small LED indicator lights; a red that indicates "ON", a front panel white that indicates "Playback" and blinks until a USB signal is locked and a small amber LED on the rear above the USB input which indicates a live USB connection. This amber light extinguishes when the power is turned off, indicating that the D7 is drawing no input from the USB when switched off.
The On/Off/Volume knob must be turned on to output a signal, either from the headphone jack or any of the 3 outputs. (RCA, Coax or Line Out).
As the D7 is powered entirely by USB power, it cannot be used as a typical portable amplifier, it is primarily a DAC, requiring a USB connection for all functions, and I must admit, it is very reassuring to not have to be concerned about batteries, recharging, extra circuitry, etc.
Soundwise, the Class A amplifier circuitry sounds superb, with a very well-balanced presentation that provides plenty of low-end punch as well as smooth and extended highs. I would say that this is a very neutral but accurate amplifier section with instrumental timbre being very portrayed in a very realistic manner.
Despite the limited voltage supplied by the USB input, the D7 was able effortlessly drive my 600 ohm DT880's, in fact the output actually seems to exceed that of the D12 and D6 although I have not measured and compared the actual outputs of each.
Soundstage and imaging are definitely two of the highlights of the D7. Instrument and vocal placement is precise and solid. The size of the soundstage always seems appropriate to the genre of the music and size of the venue.
While the D7 does not allow for opamp rolling, iBasso has certainly not considered the headphone output of this DAC to be a "me too" amplifier as they have chosen excellent-sounding and expensive chips for this section of the D7.
I can also understand why there is no opamp rolling capability for the D7, as the circuit board is very heavily populated with caps on the top side and many SMD devices on the bottom side. There is simply be no room for DIP sockets without having to make the entire device significantly larger.
It will be interesting to see how the sound changes with additional play hours, considering the many caps that are used in the circuit.
In summary, I feel that iBasso has accomplished their design goal of producing a small no-compromise DAC that can hold its own against many desktop DAC's costing considerably more than the D7. The quality of the headphone output is an added bonus, adding to a package that will certainly appeal to those desiring a high-quality DAC at a very modest price.
Edited by HiFlight - 12/27/11 at 1:49pm