Huh. I hadn't come across the A30 yet. That seems to be much better spec wise than a lot of the other class T stuff I was finding earlier. I actually quite like the idea of the RCA passthrough for powered monitors. I current have the logitech z2300 speakers but was looking to upgrade those at some point, so that's a great feature at a better price than the Magni 2 Uber. That being said, I liked the O2 Amp because of it's low noise floor. I'll have to look at the specs of the A30 to compare to some others in the price point.
Have any idea how the D30 compares to the OL Dac? The OL Dac seemed to have a lower noise floor (albeit only just) than the Modi 2. Of course, the aesthetics of a matching stack are always nice to have, so the pre-amp option on the A30 is now very intriguing to pair with the D30!
The D30 is better than the ODAC. Basically the D30/A30 is a better o2 stack.
http://www.tpdz.net/en/products/d30/index.htm
https://www.jdslabs.com/products/176/ol-dac/
http://www.tpdz.net/en/products/a30/index.htm
https://www.jdslabs.com/products/35/objective2-headphone-amplifier/
The A30 has the advantage of multiple modes, 3 selectable gain levels.
On the "low power" side the max output is just a bit more than the O2 (which some people find anemic for high draw headphones) and on the high power side its 1551mw which is more than enough for even the most demanding of Cans.
Personally this was the winner for me because I tried the Schiit Fulla2 and with only a 550mw max output and a 1.7db gain it was already too loud with my Panasonic HD-10s and my 1More Triples at around 9 oclock on the volume Pot, whats worse is that the Magni2 Uber has 3x the power of the Fulla2 and many people have reported that its basically unusable with lower power/more sensitive Cans/IEM's.
Personally more and more headphones are coming with lower power requirements and higher sensitivities due to people listening to so much music on their phones. This makes these Amps fundamentally bad for many of the headphones on the market. Giving you basically 0 volume adjustment capabilities and the need to use resistor boxes or buffer jacks (which also alter sound quality a bit) to drive lower power Cans/IEMs.
Also the build quality of the A30 is top notch and it has an upgradable OpAmp but already uses a very high quality OpAmp out of the box and all the rest of the parts are top quality aswell.
On the side of the D30, it basically does everything even with DSD support (if that is your cup of tea) it uses the top end Xmos chip found in DAC's that are sometimes upwards of 10x as expensive. Its implementation is beautiful and it uses high quality TI Opamps and high quality capacitors.
I have tested the D30 against the Fulla2 (Uses AKM 4490, and the SMSL M8 aswell as the FiiO K1 and the HTC 10). The D30 has an analytical sound like that of OLDAC and is incredibly resolving. I prefer its sound to the SMSL M8 which has filters that tend to modify the sound a bit (for this reason it seems the D30 is slightly more resolving) and its much better than the K1 (even if the K1 is good for its very modest price).
The HTC 10 has been praised for excellent quality and the D30 is on part with it, although the HTC 10 is a DAC + Amp (obviously as its a phone) and its sound is more warm, therefore the comparison isn't the same as the rest of the devices since I routed the Fulla2, SMSL M8, Topping D30 all though the A30 for testing. I also tried it the other way with routing the D30 through the Fulla2 (Amp section) and testing the Fulla2 stand alone. In all scenarios the D30 is the clearest and most analytical sounding.
The Fulla2 is a brighter implementation, things sound a bit more musical and "fun" but for this reason its not as resolving especially in complex Jazz/Classical pieces. The Amp is even brighter and brightens up the D30 a bit aswell when I'm using its Amp portion (did it for testing purposes, and because the A30 didn't arrive for 3 days after the D30 was already here).
I haven't tested the SMSL M8 -> Fulla2 Amp but I don't believe that I need to (although I will upon request) because I already know that the Amp in the Fulla2 is a bit more bright. Many people have said that the Fulla2 sounds just like the Modi/Magni stack (and that would make sense as it shares most of the same components).
Sorry for the wall of text but I hope it is helpful to you
