I’m posting this part of my reply for others as well, since I don’t want others to think the Go Bar is unusable with sensitive headphones! It is usable, as my experience shows:
I have tried the IEMMatch feature, and it works well actually. if I set it to 3.5, it lowers it enough that I can still hear the hiss, but at the 4.4 setting I can only hear the hiss if I really listen for it. Unfortunately, it steals a little bit from the low end and bass, which is weird… It certainty doesn’t affect the quality of the sound at all, its just the Andromeda headphones, they are known to have a change in frequency response based on output impedance of the source. I’ve long heard this with my ears, and then I later saw a graph on Crinacle in their IEM frequency response database for Andromeda 2020’s (the model I have) where they measured with a standalone IEMMatch, and indeed there is more bass roll-off… These headphones are picky!
The Andromeda’s like more power than you would think… They sing when given some good juice! Also, the features like the filter settings and the X Bass and X Space are amazing to have. Buying the DDHifi TC09S Nyx USB C to C cable really did help too, so for others this is actually a solution. You will still hear a hiss between songs, but during music playing it will be absent, it is so low you won’t hear it in quiet passages. I would say that this is a great pairing because the quality of the Gold Bar is amazing, and the Go Bar isn’t supposed to be *that* far behind, and the Andromeda’s can take advantage of that quality. The soundstage is so vast, that when watching movies you can hear as though you are listening to a surround sound system. When listening to music the sounds come from behind you, in front of you, to your sides, all around! You can hear every last detail too, things I’ve never heard before in music I’ve been listening to all my life!
I have been planning on buying custom Campfire Supermoon’s sometime too, and those are quite insensitive planar IEMs (15.5 Ohms, 94 dB @ 1 kHz: 54 mVrms). The Gold Bar should be a decent pairing with those beasts, I hope!
I know that its almost impossible, or it may actually be impossible to design a headphone amplifier with both high output power and a low noise floor for super sensitive headphones! It really is one or the other, either you design an amplifier for sensitive headphones that has lower output power, or you design a powerful amp and it will have a higher noise floor. Personally, I bough the Gold Bar for its quality, which is unsurpassed by cheaper, less powerful amps with a lower noise floor, so I’m OK with the hiss, especially since I’ve found a way to make it better with a better USB cable! Also, I am thinking of buying an iDefender and trying an external power source for the DAC to give it clean power when its hooked into my laptop. that should also help!
Its the analog output stage, not the chip that is in it that makes the difference. The engineering that goes into the analog output and the signal path after the chip in the analog stage will make two DACs that have exactly the same chip sound different from one another!
This is apparent on iFi products, like the Gryphon and the Diablo. They both use a Burr Brown chipset, yet they sound different, with the Diablo having wider and deeper soundstage, better bass extension with cleaner notes, not to mention higher output power and a blacker background with sensitive headphones. Measures better too, with higher dynamic range, THD/N and SNR, leading to cleaner sound with larger differences between the softest and loudest notes.
The power supply is important too, this determines the noise floor of the DAC, and a lot more. The power supply filtering and the quality of components used there is another factor separating the cheap from the more expensive DACs, but I think its secondary to the engineering that goes into the analog output and how the chip is incorporated into the analog stage.