Looking for warm tube preamp (should pair well with Pass power amp), budget $6000

If you want to get a warmer sound from your SLP-05 try some NOS tubes. I love the old Sylvania tubes in it. Fuller and smoother then the stock tubes and just all around better sound. If you want a much warmer sound try NOS RCA tubes. I prefer the detail of Sylvania’s but everyone has a different taste and depends on the rest of your equipment. Try Brent at audiotubes.com. He’ll be a great help and his page tells a lot about the sound of different types of NOS tubes.

A tube change can greatly alter the sound. With new production tubes there sometimes isn’t as huge a sound difference. Some are just bright and edgy.

Disagree with the idea of ditching the Pass power amp for ARC when OP is looking for warmer.  I've owned a number of Pass amps, most recently XA25, and currently have a Ref 75 SE.  ARC can be eye opening and very impressive, but doesn't have the warmth, richness, and density of Pass.  They are just different sounding.

As far as preamps, something 6SN7-based like the Cary might the ticket.  I like Von Gaylord as they definitely have the midrange magic, but are minimalist in terms of features if that's important to you.  I also had the CJ CT5 with a Pass XA30.5, which was a great match.  Warm, but pretty open sounding too.

Good luck!

If you want to get a warmer sound from your SLP-05 try some NOS tubes. I love the old Sylvania tubes in it. Fuller and smoother then the stock tubes and just all around better sound. If you want a much warmer sound try NOS RCA tubes. I prefer the detail of Sylvania’s but everyone has a different taste and depends on the rest of your equipment. Try Brent at audiotubes.com.

there are NO NOS tubes you can sub for a 6H30 except a 6N6P - most would go into meltdown at the operating points they run at: they are mini power tubes. None would have anything like as low an output impedance. Their characteristics are very difficult to even come close to.

For the Cary SLP-05, it uses 6 6SN7’s.  Two for the balanced inputs and for for the balanced line section.  Not sure why your mentioning the 6H30 and 6N6P.  What am I missing?  I was only talking about retuning the SLP-05. 

Aric Audio Motherload 2, I pair it with FW F8, F3, and Pass XA25. Fantastic!

I swapped in Odam coupling caps, smooth and very clear, fast and transparent.