@kckrs re: ‘And the need to have tube replacement done at the factory seems extreme’,  I’ve owned ARC amps and preamps for over 35 years. I’ve had no issues replacing my own tubes. 

Might want to consider a TVC, particularly if you do not need the additional amplification of a preamp.  Several advantages, likely discussed in other threads.

De Havilland Mercury 3 preamplifier

Kara Chaffee, designer,  sent me a new set of tubes.  I installed and well....great.  Still didn't like the bass.  A bit muddled for my tastes.  She then suggested  replacement of the rectifier tube.  Even sent me a link on eBay for it.  

NOS SYLVANIA JAN-CHS 5931 5U4G Rectifier Tube Triple Mica.  

She said she liked the tube.  Game changer for those with this preamplifier.  Addressed the bass issues and improved everything else.  Thank you Kara.
 

My experience with her piece.  Best of luck.

@kckrs

I have a Don Sachs all in pre with premium Dawning Series we6sn7plus tubes that I'm putting up for sale if you might be interested.  It has served me well with everything I have ever mated it to.  Contact me if you might be interested.

Hi,

I own both versions of Quicksilver line preamps (non-remote and remote) and I thing you have to spend 3/4 times of what they cost to get a better sound from a preamp.

No phono stage. The non-remote sound marginally better.