I used to run a 32' Purist Dominus RCA IC from an Aesthetix Callisto Sig to CAT JL-3 amps and there was not a hint of hum or noise. So keep the non-balanced option open indeed.
But if you do become set on a balanced product, the Callisto Sig meets your requirement to a T.
As for going back to 1980s vintage gear, once you get used to the refinements of newer products, i.e., low-level resolution and clarity, often due to the significant improvements in passive parts, it's REALLY tough to let that go.....no matter how much "warmth" or "bloom" or other distortions we liked so much before. Relaxed or mellow upper frequencies do not have to come at a cost of layers of details lost elsewhere.
But if you do become set on a balanced product, the Callisto Sig meets your requirement to a T.
As for going back to 1980s vintage gear, once you get used to the refinements of newer products, i.e., low-level resolution and clarity, often due to the significant improvements in passive parts, it's REALLY tough to let that go.....no matter how much "warmth" or "bloom" or other distortions we liked so much before. Relaxed or mellow upper frequencies do not have to come at a cost of layers of details lost elsewhere.