We also have a tube system, and the most transparent cables we have found are either the Verastarr Silver Reference (or Signature) or Z-Squared Au/Au, with the Verastarr's sounding the cleanest. I would describe the Verastarr's exactly as you did in your post. The Z-Squared cables have a little more body in the low mids.
Every other cable I've tried, and I have tried at least fifteen at or above your price range, veiled the highs. I have not heard the Signal Silver cables, but their Analog II does not sound transparent IMO. The AU24 was as described by Stehno, but to my ear it did not fit your stated requirements. And it too smoothed over the highs in our system.
We have a SET amp with 104dB horns, so transparency is our goal, FWIW.
Every other cable I've tried, and I have tried at least fifteen at or above your price range, veiled the highs. I have not heard the Signal Silver cables, but their Analog II does not sound transparent IMO. The AU24 was as described by Stehno, but to my ear it did not fit your stated requirements. And it too smoothed over the highs in our system.
We have a SET amp with 104dB horns, so transparency is our goal, FWIW.