Preamp... Solid State or Tube

I am looking for 2-ch preamp that must have HT bypass option to mate with my existing HT processor.  

My budget is 10K for this upgrade.  Couple of preamps comes to mind but I have no experience with these components.  

Ayre KX-5 Twenty
Aesthetix Calypso 
My system consist of following components, 

Speakers - B&W 800D2
Source - Aurender N10,  Modwright Elyse DAC, Raysonic CD-128
Amps - Modwright KWA150SE (Pair of them being used in bridge mode)
Processor - Krell 707
Cables - Verastarr Grand Illusion Statement and Signature series

Any recommendations will be highly appreciated. 

David12,  the MW LS36.5 can be upgraded to the two box DM here in The States. It has to be sent in to ModWright as it is an extensive procedure. Unless something has changed I know Dan does offer it as I spoke with him on the phone when I ordered my unit. You being in the UK it likely would be too expensive to send it back so maybe it's not an option across the pond. I'm sure eventually I'll send mine into Dan but for now it is sounding great with the little tweaks and tube options I've done.


Thank you for providing such a detailed and lucid response. This is why I love the A'gon! My enjoyment of music and audio go back 40 years but I've not schooled myself in the technical aspects of this hobby. There are so many folks on here that have so much knowledge and wisdom to contribute and I'm grateful.

Impedance matching is a no-brainer. It's (at least in the case of tube preamps) the values of the output capacitors. 50k is way too low for tube amps, which run in the mid- 250k-ohm range. Fifty should do you fine for a s/s amp. Coupla solder connections and you're good to go, and probably upgrade the caps that are in the retail pre-amp as well. Murndorf silver-oil or gold-oil are the best.
After 45 years as a stereophile there are only a handful of preamps on my short list. And at the top of the list is Ken Stevens CAT SL1. His all tube with outboard power supply has the features you are looking for and be had 7995 line stage only or 9995 with an incredible phono section. I hope this helps!