Another tube preamp "What should I buy" question.

Congratulations!

Happy for you mate.

Did you consider the Audio Cary SLP-05?

I am in a similar situation looking for a long term preamp. My system is currently comprised of Gustard R30->Anthem AVM90->Simaudio Moon W10->Aerial Acoustics 20Tv2s and have an issue with the upper end sounding a bit clinical and harsh. AI has suggested that the SLP-05 would be a top contender and Rhumba Extreme 1.4, Motherlode XL and PL400EVO are also great contenders.

To @rowester,  good for you. I can imagine you are going to like this preamp feeding your Michi S5. That’s a neat amp. I’ve been retracing old Rotel steps myself. It’s been enjoyable using a 6SN7 tube preamp to feed any of my former solid state or tube amps. The newer tubes are getting to better too. Trying different 6SN7s to achieve a particular sound can be fun. It will be worth the wait. 

These for $6,500? I haven’t seen trustworthy reviews of them. It seems a high price tag has become a defining characteristic of boutique brands.  Yes, Jupiter caps, Takman resistors, Clarity film capacitors, etc., might be high quality—but how much can they really add up to?

This type of pure wire-to-wire design may offer a shorter signal path and fewer components, but it provides no isolation between components and stages (although PS is in a separate box). A well-implemented isolation scheme can reduce noise far more than extra components degrade the signal. As a result, pure wire-to-wire design is often less preferred in truly high-end gear.  Go ask diyers.

Apologies if someone else already mentioned this.

Over 20 years, I would want to send it in for a checkup a few times, thus you need to guess if the maker will still be around, and if they have as history of long support for their products.

Then, you need to hear it for yourself, perhaps, if needed, take a vacation, near someone who has one. 

Or, buy with return options,

5% restock never killed anybody. (see movie 'used cars')