Certainly. Make it a great one though.

I don't know anything about it, but I bet it works fine. You'll love the sound of the Rachel!

I use a Tube Nirvana Aretha with mine. I wanted more bass since I listen at lower volumes, and the ZROCK wasn't available.

It is 6SL7 based and sounds great!

I bought a CSP3 off the forum here, send it back to the Zen Master to transfer the warranty and change out the base from black to a walnut to match our Rachael & ZP3. I really liked the Rachael & ZP3 combo but now will never part with the addition of the preamp. Better in every respect. Happy listening, Chris.

Since I have not found specs for the Rachael concerning input sensitivity, and input impedance, then what you are left with is to try it and see.

I've used the Schiit Saga with the Rachael. I initially got the Saga primarily to add remote control of volume. I ended up returning it during the 15-day trial period to upgrade to the Freya. Saga has unity gain with a tube buffer stage; Freya has 14db of gain via its tube gain stage and a 128-step volume attenuator vs. the 64-step version in the Saga. The ability to ride the gain to better tailor the sound—which Steve recommended when I e-mailed him regarding the pros/cons of adding a preamp—was what motivated the upgrade. I was otherwise not unhappy with the Saga.

Equally sorry for the delay in responding--haven't checked this thread in a while. My main preference for the Freya over the Saga was the gain stage. It provides a denser/fuller sound with my speakers (Spatial Hologram M3 Turbo S's) in my main listening room (~600 sq. ft., open concept) than the Saga did. YMMV depending on your speakers, system, and room. I would certainly consider the Saga in the future if I needed a pre for a near-field setup in a smaller room.

I did get the tube pre-amp from tubeman, and in many ways, I like the combination. I have also tried other little tube pre-amps, and there is a marked difference from one to the other. Whether it is voicing, gain, or distortion, it is all easily heard through the Rachael. So then it becomes a matter of preference.
NOTE: I have recently sold my Rachael, and yes, I do miss her dearly. Progress in experimentation cannot happen for me without new funding. This was the way to provide it quickly, as the unit sold in a few hours. The new experiment will be using a tube based Pre-amp with a SS unit, currently in the process of being rebuilt/redesigned by a knowledgeable engineer. As time goes on, it is a possibility that I will go ahead and build the SS amp kit offered here, just to some music. Later, a new horse race begins...!

I wasn't too impressed with the PS Audio BHK preamp, for the price there are a lot of outstanding offerings. I preferred my CSP3 with 25th mods over it in all areas. Down side is the CSP3 doesn't have remote volume control if that is something you want, the ZTPRE does have remote volume control and might be worth considering.

If you want something a little different an autoformer might be interesting to you. It's a passive device. You can get a true passive, or like I have, an EMIA Remote Autoformer and love it! It offers expansive soundstage, rich harmonics and shocking speed. I'll stop myself before I start gushing over it.

My brother sold his PS Audio BHK for an EMIA Remote autoformer with silver transformers. He does bring up trying the ZTPRE from time to time.

I don't have any experience with Brinkmann products.

I am considering purchasing a Rachel (maybe 2) and pairing with a Mcintosh C22 V3 (relatively new model) preamp.  Will be driving various sets of Klipsch (Khorns, La Scalas, etc.)  Would the Mac be a good match, and if not, why not?  Thanks for any help.

Just a short update:  I acquired aVTL 6.5 series ll preamp.  The overall improvement to the soundstage, depth and spaciousness was nothing short of amazing.  The Rachel is at the top of its game with the Brinkmann Nyquist and VTL.  Now I know some of you will say it should given the high prices of the VTL and Brinkmann.  But the Rachel with rolled tubes and these high quality input devices is just off the charts