Ahead of sound impressions … some other thoughts …
General
As claimed, the Cobalt is a bit smaller than the Red and Black models. The finish is quite a bit darker than the official pictures seem to show show. The package is the usual form-fitted plastic tray inside a box. And you get the normal DragonFly slip-case that accompanies the other models with the (welcome) addition of a USB-C equipped “DragonTail” cable/adapter/extender.
Build
Unlike the Black and Red models, this unit rattles if you shake it and this is clearly due to the PCB, to which the USB and 3.5mm connectors are directly mounted, moving around in the case. You can easily see and hear them wiggling if you shake or move them.
I don’t know if the original versions were potted, were just a more tightly toleranced fit, or had some additional support, but both the Red and Black models feel a lot more solid than the Cobalt in this regard, which is surprising given the price difference.
This has been reported elsewhere, also. It seems more prevalent than not (i.e. there are some units that don’t have any play in the connectors). About half the people that contact AudioQuest about it said that they were told it was a defect, the other half appear to have been told its normal.
Unsupported TRS connectors for headphones, especially on mobile devices, are something I personally consider to be a potential problem.
Drive & Headphone Matching
If your current headphones play well with the Red, from a power perspective, they’ll play well here too.
This is not surprising as the Cobalt uses the same output stage, the same voltage rail ratings as the Red and consequently drives headphones with about the same ability. If you’re looking for more power/grunt or to drive more demanding headphones than the Red then you will not find it here.
I was surprised how well it drives the Rosson Audio RAD-0 … but harder to drive stuff is not better off than it was before:
Quirks:
Something I’ve never seen on the Red or Black models, but ran into immediately with the Cobalt, relates to how you connect it up. On the Red or Black it never seem to matter if I plugged the headphones in, or out, with music playing, while being driven from the iPhone.
On the Cobalt, several times now, swapping headphones on the fly has triggered the “This accessory uses too much power” message, resulting in having to disconnect and re-connect everything. In normal use, just connecting your headphones before connecting to the iPhone will avoid this - so shouldn’t be too much of an issue.
Proper sound impressions to follow …