I have a Delos. I do not hear a rising high end at all. It sounds completely neutral in that regard. It is loaded at 183 ohms into a lundahl 1941. And why would you say that it sounds fine on good Analogue Production records but wrong elsewhere? I find it hard to believe that the vast majority of recordings have a rising top end, or conversely, that Analogue Production records are all rolled off in the highs.
Maybe your hearing in the higher frequencies is better than mine?
FWIW, I also do not find the Delos to be lean and/or analytical in my system. I keep reading that this is the Lyra house sound. But it does not apply to the Delos. Each recording sounds distinctive - as they should. The Delos reveals the positive and negative attributes of recordings so clearly that I have no doubt that I am hearing a good chunk of what was captured. Great performances with solid engineering are magnificent to listen to - and there are thankfully many such records to choose from.
Maybe your hearing in the higher frequencies is better than mine?
FWIW, I also do not find the Delos to be lean and/or analytical in my system. I keep reading that this is the Lyra house sound. But it does not apply to the Delos. Each recording sounds distinctive - as they should. The Delos reveals the positive and negative attributes of recordings so clearly that I have no doubt that I am hearing a good chunk of what was captured. Great performances with solid engineering are magnificent to listen to - and there are thankfully many such records to choose from.