Since the Cayin YB04 is so goddamn neutral, you should be cautious with your source. It takes on the voice of the amp with enthusiasm. If the source is too neutral/analytical, these monitors could become very boring very quickly. I recommend warmer devices with a strong, robust character.
I suspect many are interested in how the Cayin YB04 pairs with the Cayin N6ii ($1,099). Both are flagship products from the same company, and you oughtn’t be surprised to know they vibe beautifully with one another. The N6ii is a warm, powerful DAP, with equal parts clarity and resolution. It adds boldness and heft to the YB04, and the soundstage has never felt bigger. If you desire to ride a full-on Cayin stallion all the way to Pleasure Town, this is a sick system that I really dig.
However, for those who are extra weary of the YB04’s tuning, the iBasso DX220 with AMP9 ($899 + $250, Review HERE) is my recommendation. The Korg Nutubes of AMP9 meld with the already rich signature of the DX220, creating a beast of refined musicality. Something the YB04 needs as much of as it can get. In general, I like the N6ii best, but for this IEM, I prefer the iBasso system.
Shanling has a brilliant option that gives you much of the iBasso sound but at a significant cut in cost: the M5s ($409, Review HERE). It is gloriously musical, with bad-ass dynamics, and a silky smooth tone. The YB04 eats it up, becoming imbued with its virtues. If you’re on a budget, it’s hard to do better.
I met delightful results with my new tube amp, the xDuoo TA-20 ($366). There is no hiss, which is something I worried about, and the amp filled out the YB04 like a motherf**king boss. These in-ears suddenly had meat on them bones.
Sadly, the Cayin N5ii did not make the greatest companion. It’s too neutral, and makes the YB04 too bright.
My favorite of the budget players, the Hidizs AP80 ($150, Review HERE) sounded pretty good. It paired better than the N5ii, but I felt it could use a little more warmth.
Now, the Shanling M2s was perfect. Like the M5s and the DX220, it had all the warmth and richness to help the YB04 reach its potential. Although the M2s is discontinued, I suspect the M2x ($219) retains its predecessor’s spirit.