I have had my Rachael amp for about 6 months now. It's an excellent piece and the the main amp in my system. After experimentation with different combos my chain is as follows:

- Digital: Holo Audio Red (streamer) > Pontus 15 (DAC) > PS Audio BHK Pre > Rachael.
- Analog: MoFi UltraDeck w/ Hana SL mkII > PS Audio Stellar Phono > BHK Pre > Rachael
- Cables: Pine Tree Audio Scorpion Power Cable, WBC RCA interconnects, Pine Tree Audio Rainbow Ribbon speaker cables

For speakers I have 2 setups I have been using and both are excellent with the Racheal. Hard to say which is a favorite. Depends on mood. First speaker setup consists of the Caintuck F-15 Magnum and a W-15 Magnum powered by a Crown XLS1002. The open baffle speakers are wonderful. Adding the W-15 bass baffle to the F-15s is a magical combo for the Rachael. If you like soundstage and open and airy sound look no further.

My other speaker setup is a set of recently acquired Klisch Heresy II w/ Crites tweeter and crossover upgrades paired with a Rel s/510 subwoofer. I won't bother with anymore audiophile babble descriptions of the sound. Suffice it to say this a combo I could live with for a good long time. This my first set of Klipsch speakers. Call me impressed.

I have rolled some tubes with the Rachael. I find the stock Delaware tubes to be really good and provide a nice holographic soundstage and very easy to listen to. I find them a little soft around the edges for my tastes. Thus far I have tried the following tubes in various combinations:

- Rectifier: Deware 5U46, Psvane Horizon 274B, Ray Select 5U4
- Power: Decware EL34, Psvane UK-EL34, Psvane EL34PH, Cryotone EL34, Psvane Horizon 6L6

The combos I prefer the most are the 274B/EL34PH and Select 5U4/Cryotone EL34. The EL34PH are a good all around tube and sound good with all the rectifiers. The Cryotone EL34 are something else, but can be a little much to my ears with the Decware 5U4G and 274B rectifier. With the Select 5U4 the Cryotone EL34 maintains its soundstage, dynamics, slam, and clarity without the edgy treble I got when paired with the other rectifier tubes.

The Rachael sounds good without the BHK preamp but I like being able to remotely control the volume. Also, the BHK allows me to connect the Pontus  15 and Stellar Phono via XLR and feed the signal to the Rachael via RCA. The preamp does ad a little juice to the signal which I like.

In sum, I'm completely happy with the Rachael as the anchor of my system. I can't say for sure, but at this point probably have over 500 hours on the amp and would swear it's still improving sound wise.