So I thought I'd share my thoughts on the CLAS -dB with a few different balanced amps and using different transports and ear/headphones. These are very early impressions and therefore not a full review of the CLAS -dB.
Left: CLAS -dB (pre-fix) + self-custom (workaround) ALO balanced IC + ALO Rx Mk3 + balanced FitEar 000 + FitEar TO GO! 334
Right: CLAS -dB (post-fix) + ALO balanced IC + RSA SR-71B + balanced Beat Audio Cronus + Unique Melody Merlin CIEM
Fostex TH-900 in single ended 1/4" -> 1/8" adapter :-
The Good Things
Balanced All The Way Throughout
Oh my, once you've gotten balanced to work nicely, it's almost hard to go back! I'm a definitely a believer of portable balanced despite in theory it may not necessarily make sense. Even with IEMs I hear an improvement of "bigger sound" - bigger soundstage, tighter yet deeper bass, and airy trebles. And with the TH-900, it's even easier to discern despite using being single ended. If I dare say especially for IEMs, I find that the backend IC of SE vs balanced to be a greater difference than with IEM cables SE vs balanced. In other words, at least in my experience if you own IEMs balancing IEM cables yields less rewards than balancing the IC between the DAC and amp.
Some tracks such as HDTracks Buena Vista Social Club at 24/96 via PC USB sounds so involving. I've not compared to my iDevice version of the same album but despite iOS's 16/48kHz limitation, I don't think it'll make too much of a difference in this respect.
Some Thoughts Of Rx Mk3 vs SR-71B
I've mentioned on some other posts that despite owning the SR-71B I've never really been a fan of it and that's mainly because I've been using it in SE mode. In the past few months, I've tried balanced cables for my IEMs and I still wasn't satisfied with the SR-71B. So finally when the CLAS -dB appeared I finally could try a fully balanced setup with the SR-71B and it's only then that the SR-71B started to shine more. It seems to benefit more from a backend balanced IC than from the frontend balanced earphone cables. Or maybe the SR-71B is simply not so IEM friendly.
On a fully balanced setup of Rx Mk3 vs SR-71B, I think it's now more a merely of personal preference of taste rather than which one is more superior than the other. To me the Rx Mk3 still has the more modern Hi-Fi sound of great bass and treble emphasis whilst the SR-71B has a stronger mid focus. I'd consider my listening to be still somewhat more immature so for me, I'd go for the easy Rx Mk3 as my preferred sound for all the genre of music I listen to. However if I'm listening to specifically strong vocals such as Adele or Lana Del Rey, then I may enjoy the SR-71B a tad more (but not by much).
iDevice Battery Recharging
The battery recharging to me is an absolute bonus. So often my iPhone 4S battery drains quickly (especially on Tapatalk checking Head-Fi so regularly!!). So this battery charging is a huge blessing. But how is this different from my Go-DAP 4.0? The Go-DAP 4.0 (or X for that matter) runs out of juice in an hour despite having a 2200mAh battery whilst the iPhone 4S having a 1432mAh. This means David at CypherLabs has gotten something right about charging the iPhone. I don't know what size battery he uses but I think I'm more inclined to to think he's placed some thought and logic to charge the iPhone intelligently rather than just brute battery size.
Regardless, all the requests and questions potential customers have asked of how to switch off charging, to me it's no harm having the phone charging all the time. With a full iPhone 4S battery charge and the CLAS -dB plugged in, it lasts for 14 hrs. If the iPhone 4S is empty, the CLAS -dB charges the iPhone in 2 hrs 15 mins and still continues running to play music for a further 3 hrs at least (in my trials). So to I don't care if there's no switch to disable charging.
EDIT: I've snipped off the issue I had about the hum I got in high gain when using PC USB -> CLAS -dB -> Balanced IC -> Rx Mk3 -> headphone when touching the Rx Mk3 chassis. I think this hum is specific to my setup after talking to a few ppl. In addition, I don't use high gain for my setup, nor do I use the PC USB as much as I do with an iDevice.
Conclusion for Personal Use
When I've got my rig setup properly, I'm actually very happy with the setup and a fully balanced portable rig truly works. Balancing isn't for speaker or long cable setup but it seems even portable setups can benefit from it.