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

After much research I went with a Zesto Leto tube pre to go with my Mola Mola Kaluga monos. I am very happy with the result. Not sure if it fits the definition of warm, but it has made me very happy. American made and they have exceeded my expectations.

I have a Cary SLP 98 I can let you have for $2000. Let me know.

@russbutton Should I build a SP14?

And btw I got a 6550 tung sol coming in Ill put in the ARC.

@smodtactical 

You've made a significant investment with that ARC preamp.  Stereophile called it a reference piece of gear and that's not something they do lightly.   Since you have the 6550 tung sol tubes coming, you should definitely see what kind of difference that makes.  But chances are with that preamp, I'd expect there to not be big changes.

I think you'd get more enjoyment out of building a preamp than you can imagine.  You become much more involved in what you're doing.  The SP14 uses 6SN7 tubes and there are many different brands of 6SN7, so you'd definitely have more to choose from.   The cost of the SP14 kit is low enough relative to what you've obviously spent elsewhere in your system that you can afford to experiment.

It's a little like comparing the experience of buying a new, hi-end Porsche versus an older sports car that you do all of the work on during weekends.  The new Porsche is an exceptional machine.  Too perfect perhaps.   But that 50 year old Triumph begs for you to know every inch of it before you even get in.

If you really want to get your hands "dirty", consider building an Aikido circuit preamp with one of the boards from Glassware Audio.  It's the same circuit that the SP14 uses, but you'd be using a different power supply and you'd be building it all from scratch.  Then you get a lot more choices regarding power supply, caps, stepped attenuators, etc.  Now THAT would be fun!

@smodtactical I've built two SP14 preamps using the tubes4hifi.com boards.  You can build it for less than $500 including upgraded capacitors.  The build is quite straightforward with building and wiring to the chassis the biggest pain.  The SP14 sounds very nice but it doesn't outperform my heavily modded Cary SLP-70 although it comes close.  I have yet to succeed in building a SP14 that is completely quiet so that will be a problem if you are planning on using it with efficient speakers or a high powered amp.