In the past 2 years VentureCraft has been successfully creating amps and DAC/Amp packaged components with their GD-03, Go-DAP 4.0 for iPhone 4(s), and Go-DAP X for their multi OS (iDevice, Android 4.1+, PC USB Audio).
This is VentureCraft's first DAC-only product but with a twist. Leveraging on the existing AKM AK4353 used on the Go-DAP 4.0 and Go-DAP X, they have continued with the trend of using the same DAC in their DD. The difference between this iDevice DAC with it's competitors is the multiple choices of pre-amp OpAmps offered - OP275 (base standard), OPA627AU, Muses01, and Muses02.
As with the other Go-DAPs, the DD Socket 1 comes with a 2200mAh Lithium that can be used to charge the iDevice during play, or dedicated for the DAC use. It sports a Toslink optical and coax out and therefore can be used as a digital transport. It also sports a 9Vrms output to drive the internal OpAmps.
The different OpAmp pre-amp options are rather interesting. Each OpAmp ever so slightly influences the output from the DAC prior to feeding into the amp. In this case the loaner DD1 Socket 1 I have from VentureCraft is the OPA627AU. As such I've paired it with a matching Leckerton UHA-6 MkII with a pair of OPA627AP installed.
DD Socket 1 with OPA627AU OpAmp pre-amp
Leckerton UHA-6MkII with also a OPA627AP OpAmp.
Headphone Lounge (Chris_Himself) Silver/Gold OCC cables with Rhapsodio RDB+ v1 and FitEar tips
With the aforementioned setup, the DD seems to present a mild and mellow signature that seems quite suitable with Jazz, Classical and generally slower genre. There's also a touch of lush warmth to the signature giving a slight sense of richness to the overall signature. Despite that lush richness, detail isn't lost but more subtle rather than a glaring "right in your face" approach.
Despite being warm though, it doesn't focus on deep sub-bass but "warms up" more from a mid-bass to upper bass area. MIdrange is also rich with detail which starts to show its' emphasis in upper mids - tracks with strong female vocals benefit from this. The trebles extend high and maintain a sense of airiness without any harshness.
Aside: For no logical reason, I'm a believer of burning in amps but not DACs. This DAC with an OpAmp pre-amp is therefore somewhat unique. I've opted to burn it in to smooth out the highs. As such my comments the absence of harshness or brightness.
This DAC definitely presents an interesting alternative to the current Fostex HP-P1, CypherLabs Algorhythm Solo, and other iDevice-supported DAC offerings. In terms of it as a DDC, it supports both Toslink optical out like the HP-P1 but also with a Coax like the CLAS. An added feature which is shared with the current CLAS but not with the Fostex HP-P1 is that it can charge the iPhone. Some of the idiosyncratic charging operation is that it has to be "switched on" to charge and the operator must remember to switch off when disconnecting the microUSB charging cable (or the battery will drain). Its DAC function is also disabled whilst it's being charged - as such the use and charging operations are mutually exclusive.
Sound-wise, despite all 3 aforementioned iDevice DACs are from the same manufacturer of DAC by AKM, the models are different and in addition with the DD Socket 1's ability to swap OpAmp pre-amps provides some flexibility to the DAC that the others can't. The different DACs can influence the lineout before getting fed to the external amp. As such instead of swapping DACs altogether, one could just swap the OpAmps to have a slightly different flavour.
The DD Socket 1 is a refreshing addition to the portable iDevice DAC world.