I think you mentioned earlier that you agreed with
@Beolab who stated the Pro iCan sounds a little flat. So, my opinion may not matter much since compared to other gear I own, to me, it doesn't sound flat. Then again, I'm not quite able to afford things much more expensive. But what the heck, I'll throw some opinions down.
I connect the Mojo, Jot, H2 to the iFi Pro iCan (Also had the iDSD BL for a while earlier this year). The Mojo I only connect because it is acting temporarily as my in home streaming client while waiting for the 2Go for the H2.
The Jot has the older DAC in it, rather than the more recently available multi-bit dac.
I'm expecting the RME ADI-2 DAC too next week. Previously a friend brought his to my home to try it out for a few hours and I loved it with the iFi iCan Pro, so decided to get my own.
As a DAC that is a little more than the iDSD BL, and significantly less expensive than the H2, and with balanced outputs, I would throw that idea in as something to consider.
It has balanced outs. To me, the RME, out of the RME's own headphones ports, doesn't quite get to toe-tapping fun. The Pro iCan, on the other hand, is rather beautiful sounding, a nice hollow sound, at least compared to the headphones ports of each of the moderately priced DAC/AMP's I own. So the pairing with the RME works really well for me and I pulled the trigger earlier this month on back order and expect it to arrive next week (Finally! What a long wait, those things are always out of stock). The RME has a lot of eq controls, which, I really like. The customization on the RME + the little bass boost on the iFi iCan Pro, gives a ton of flexibility to get pretty much any headphone closer to my preferred sound profile (within limits, obviously). My other option was to get the $149 Schiit Loki and put it between an unbalanced DAC output and the unbalanced iFi Pro input. It's cheap enough that I still might consider it down the road, but for now, the RME seems the better option.
The other one already stated is the iDSD Pro. It's less expensive than the H2, and seems like it might be pretty awesome.
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It occurs to me, though, that if you're comparing the iFi iDSD BL and the H2, you have another required criteria: Battery powered transportability.
If that's the case, then I think unbalanced outputs are your only option, and the H2 and iDSD BL are spot on options to consider.
The iDSD BL has the xbass feature, which can be very useful for some headphones. For the HD800, the xbass on the Pro iCan really makes this combo the only option for me when listening to large classical orchestral pieces. Such an expansive sound, and beautiful resonating bass. Being able to have that bass boost in a transportable device can be very very nice if you have high resolution, but less punchy bass headphones. If I remember right, the iDSD BL's xbass is 20hz, right? Of course, if you already have headphones with some nice sounding bass that fits your preference, that feature is a bit of a waste. It's a great DAC all around. Since obviously everyone knows that any good DAC provides a lot more detail than going straight from a computer or smart mobile device, the iDSD BL will of course be great for detail, especially for a transportable device. There's a lot there, and it's a good fit for the Pro iCan. (I purchased an iDSD BL off Amazon early this year before deciding on the H2, used it for a while, thought the H2 was better for me, and returned the BL. I regret that, and may have to go back and buy it)
Conversely, the H2 provides a level of detail that doesn't seem to matter much on slower headphones, but for me at least, makes a big difference on fast headphones like the hd800/s, utopia, t1, casscade, kse1200/1500, the H2 can really bring up subtle sounds that disappear or are harder to hear on other chains.
I will say that when the H2 is connected to the Pro iCan, I lose some detail when compared to it's own port. When I connected the iDSD BL to the Pro iCan, I seem to have lost nothing. Listening for subtle sounds that I know are there, the iDSD BL/Pro iCan didn't lose detail, but subtle sounds were harder to hear, so I had to concentrate when listening. With the H2/Pro iCan combo, I also have to concentrate to hear specific subtle sounds I know are there. I can hear them, but they're much more in the background and overwhelmed by the louder, main sounds. Whereas the H2 straight to my headphones brought up subtle sounds such that I didn't have to concentrate to hear them, they were just there.[/QUOTE
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