Testing some more today, Steven Wilson: What life brings, in Nightowl headphones from Teac Nt-505 in main system vs Topping e30ii in office system. Streaming from Qobuz. - No contest, Teac is better. No surprise. But it is a gradient. Not night and day difference.
Maybe my budget should be 600 usd. This is still ca four times the price of the Topping. With a clear sonic improvement. If this is too much to ask for, maybe I should wait.
My office system is my secondary system. I dont want to reinvent the whole system, invest in a streamer, power conditioner, top grade cables, better speakers, amps or whatever. I like it as a modest system, specialized to my liking (single driver speakers, OTL sound etc).
Yet I do want to consider good-sounding DACs. This is also based on my experience from developing the analog chain in my main system, starting from the source (there, the cartridge) and going from there.