Running your post through ChatGPT. I just did it... and added what would be the sonic differences:

Fun dilemma—you can’t really lose here. The two paths will sound different more than they’ll differ in raw power (both are ~100 W/ch with KT-family outputs). Here’s how the voicing and behavior typically shake out:

What changes sonically

Cary SLP-98P ➜ Rogue Stereo 100 Dark (separates)

• Tone & midrange: More “golden” and saturated through the mids (6SN7 magic). Vocals feel rounder, image bodies get denser; stage projects a bit deeper.

• Top end: Silkier, a touch sweeter; cymbals have more sheen than bite. Perceived air increases, “edges” soften slightly.

• Bass & drive: Weighty and tuneful but a hair looser vs the Cronus pre stage; macro-dynamics bloom rather than slam. Pace is easy, unforced.

• Soundstage: Bigger/deeper with more front-to-back layering; images float with a little more “holography.”

• Noise/gain: Slightly higher gain and tube rush possible if you crank with no signal, but with your speakers it’s a non-issue. Keep interconnects short to preserve top-end sparkle.

Rogue Cronus Magnum III ➜ Dark upgrade (integrated)

• Tone & midrange: More neutral and linear. Still tube-rich, just less rosy—tends to disappear and let the recording call the shots.

• Top end: Cleaner “ring” and transient definition; more sparkle/etch on leading edges, less glow.

• Bass & drive: Tighter, punchier, better stop/start—you’ll feel kick drums and bass articulation firm up.

• Dynamics: More immediate attack; a bit more PRaT and rhythmic grip.

• Noise floor: Typically quieter as a single chassis; the Dark parts (caps/resistors/wiring) lower grain and sharpen focus.

With your speakers

Magnepan .7 (4Ω, current-hungry, ~86 dB)

• Favors the Cronus 3 Dark: The integrated’s tauter bass and higher apparent damping give Maggies better panel control, faster leading edges, and image focus. You’ll hear snappier transients and cleaner bass lines.

• Separates: Gorgeous midband and scale, but you may notice softer bass grip and slightly relaxed timing on dense or bass-heavy material. Lovely for strings/voices; a touch polite on rock/electronic.

Falcon LS3/5a Gold Badge (15Ω, ~83 dB)

• Favors Cary + Stereo 100 Dark: These thrive on midrange color and dimensionality. The Cary’s 6SN7 bloom + Stereo 100 Dark’s body makes voices spooky-real, expands depth, and smooths the tweeter’s handoff.

• Cronus 3 Dark: Still excellent—more neutral, with crisper imaging and tighter bass from a tiny box, but a bit less of that LS3/5a “liquid” charm.

When to choose which

• Choose Cronus 3 Dark (integrated) if:

  • Space and simplicity matter.

  • Maggies are your main speakers.

  • You value control, speed, and bass definition over romantic color.

  • You want a very low-fuss, low-noise setup that punches.

• Choose Cary + Stereo 100 Dark (separates) if:

  • You want maximum midrange allure, image density, and depth.

  • You spin a lot of vocal, jazz, chamber, or acoustic.

  • The Falcons see significant use.

  • You enjoy rolling 6SN7s and fine-tuning flavor.

Cost/benefit reality check

• $1,400 Dark upgrade on Cronus 3: Big bang for buck. You’ll hear clearer transients, tighter bass, lower haze—especially obvious on Maggies. Easiest path, strongest resale continuity.

• Buying the Stereo 100 Dark and using the Cary: A larger total outlay and two chassis (more tubes, more heat), but a “heirloom” tube sound with deeper stage and richer tone. Best synergy with the Falcons.

Quick recommendation (given your rack/space note)

If you lean Magnepan and want convenience: upgrade the Cronus 3 to Dark—you’ll likely prefer the grip, speed, and focus.
If you find yourself listening more to the Falcons or you crave that classic tube bloom and depth: dust off the Cary + add the Stereo 100 Dark.

If you want, I can sketch two tube sets (driver/input + outputs) that nudge each path exactly where you like—e.g., slightly warmer Cronus Dark, or a snappier Cary/Stereo 100 combo to help the Maggies.

Wow thank you! I did CNN pick up the stereo 100 yesterday for a good deal. I listen the Maggie’s more right now so I will try the new combo with them. I do listen t mainly jazz so it should still be good. I reallylike the Cary preamp do I wanted to see about using it again. Thank you so much for your help.

Preamp into Integrated:

My Cayin Tube Integrated is designed with a Pre-In Input, to use it optionally only as an amp, it’s 6sl7, 6sn7, tone controls and volume control are all out of the circuit.

I tried it that way for a while,

then I plugged my McIntosh MX110z tube tuner/preamp into my Chase RLC-1 Remote Line Controller, and the Chase into the Cayin’s CD Input which is what it defaults to at turn on.

That runs my McIntosh preamp into the Cayin’s preamp circuit. That’s why I have my Cayin volume at 12 oclock, mx110z at 12 oclock, and use the Chase for Remote volume and Remote balance.

The Chase also has automatic and progressive bass boost only when you lower the volume below it’s default volume start which is low, a partial Fletcher Munson compensation, doesn’t boost the highs.

One advantage is that I can make temporary adjustments to the Cayin Volume when comparing cartridges, I’m standing right there when I select which arm on my SUT, and whomever is listening with me, perhaps owner of one or two of the cartridges, helps me find matching volumes for fairer comparisons.