Rogue Cronus Magnum III

Discussion in 'Audio Hardware' started by bajaed, Jan 1, 2019.

  1. Doctor Fine

    Doctor Fine "So Hip It Would Blister Your Brain"

    I forgot to add---sorry if this is obvious---but try looking for hum with your Beogramn turntable leads unplugged from the Rogue.
    That way you can see which part has the hum as you can listen to ONLY the Rogue phono section to see how loud the noise it makes is WITHOUT the Beogram adding cable or electrical noise on top of it.
    Then plug in the leads.
    Finally, swap the leads for other better shielded ones if the Beogram has detachable leads.
    And if the Beogram is making the noise due to a motor or transformer leak---try moving the turntable around to see if location can minimize the noise.
    My two cents.
     
  2. jphabc54

    jphabc54 Forum Resident

    Location:
    NoVa
    I think a bit of tube "whoosh" is normal on the Rogue -- it unlikely to be dead quiet, but you'll know when you have a ground loop hum. I chased a ground loop hum on my phono side for months. It turned out to be the cartridge -- finally on the third cartridge I tried, the hum was gone.
     
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  3. Doctor Fine

    Doctor Fine "So Hip It Would Blister Your Brain"

    I had tube hiss and some hum at first with stock JJ in center 12AU7 position in Cronus II.
    With a tube swap and proper grounding ALL the noise went "poof."
    Turn it up full clockwise---you have to put your ear next to speaker to hear the noise floor coming off the amp, it's that low.
    The stock phono section adds only a teensy tiny bit of added gain noise at full power.
    This Rogue Cronus is QUIET!
    I have a drawer full of preamp tubes and a half dozen classic guitar tube amps that I record with in the studio.
    Tube preamp sections are VERY subject to improvements with tube swapping as you look for the quietest one in your tool box.
    If you have a noticeable noise with a Cronus II something is WRONG.
    My two cents.
     
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  4. TheVU

    TheVU Forum Resident

    People with Magnum Cronus’, any version, keep talking about them. I’m on the fence for one.

    For Maggie’s and somewhat efficient box speakers (96db)
     
  5. trd

    trd Forum Resident

    Location:
    Berkeley
    Any thoughts on the sound of the kt-150s? I’m curious why they switched from the 88s
     
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  6. mike catucci

    mike catucci Forum Resident

    Location:
    PA
    This sounds like a great unit. I had a I and II and they were both stellar with some tube rolling. The headphone unit needed some work and I thought I read this one uses the tubes, not solid state. That would be a great move. I'd bet since they released the Triton II, that the stage in the CMIII is the old Triton, which would be fantastic. I love my SLI-80 but boy this amp is temping especially with Rogue being 15 miles from my home.
     
  7. gss

    gss Forum Resident

    Location:
    New Jersey
    Really looking forward to reading more impressions of the III. Bring them on: :-popcorn:
     
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  8. JNTEX

    JNTEX Lava Police

    Location:
    Texas
    Would love a 3c, haha or a 3 with no headphone, no phono and some cap upgrades and 4 lines selectable by remote with dim leds on front with a mono button (remote too). And I bet a touch more power could be squeezed out.

    Just a hint.

    But I would settle of a demo of those upgraded monoblocks they have on their site.
     
  9. gabrihamlincoln

    gabrihamlincoln Well-Known Member

    Location:
    San Francisco, CA
    My CMIII arrives Monday from HiFi Heaven. I traded in my R0gue Sphinx v1 and Schiit Valhalla 2 for a $1,200 credit towards it - pretty great deal IMO... I reached 0ut to Rogue as I had the same questions as you re: phono stage and headphone amp and received this as a reply:

    "The new headphone amp is not tube based (MOSFETS) but it sounds excellent and will drive pretty much anything. The new phono is actually much closer to the new Triton II phono."​

    Somewhat disappointing that the headphone amp is solid state (MOSFET), although since "the design is basically a simplified single ended version of [the Rogue Audio] RH-5 headphone amplifier", which is a $2,495 headphone amp, I'm sure it will sound pretty great. As f0r the phono stage, modeling it after a $1,295 unit is pretty amazing. If either are close to their standalone brethren this has to be one of the best deals out there right now.

    I'll be using it to power my Vandersteen Sig II's - impressions to follow...
     
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  10. mike catucci

    mike catucci Forum Resident

    Location:
    PA

    Looking forward to your thoughts on it!

    I would consider the Triton close to the Triton 2. Same blood lines afterall :D:D

    Yea that is a bummer regarding the headphones. It is one of the things I really love about the Cary. However you're right in that if it gets halfway to the RH-5 it should sound very good.
     
  11. Louis Grignon

    Louis Grignon Active Member

    Location:
    Montauk, NY
    I fortunately am close enough to drop off the BeoGram 9000 to Soundsmith in Peekskill. I met with mark Whitters and spen about 1/2 hr discussing the machine, the work they do and how that unit and cartridge (smmc2) fit the new equipment I have purchased. There is a discussion in another thread about cost percentage of the various parts of the system. In this instance
    Amp. 38%
    Tt, cartridge. 23%
    Speakers. 17%%
    Cd, tape decks. 11%
    Cables, etc. 3%
    Headphones. 8%
    This is how an approximately 7500 budget worked out
    I am completely happy with the rogue cmii, the Kefs ls 50
    The new sound is at a different level with tha cm II
     
  12. No Static

    No Static Gain Rider

    Location:
    Heart of Dixie
    I’m using the original CM (running KT120s) with my MMGs and they’ve never sounded better. And it replaced a pair of Outlaw 200wpc mono amps so all power is definitely not the same.
     
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  13. Louis Grignon

    Louis Grignon Active Member

    Location:
    Montauk, NY
    I received my rogue cm III about 3 weeks ago. I put it it through its break in. I see there is some discussion about noise here.
    The cm III IS QUIET. Through all sources; cd, cassette, Sirius (aux 1 & 2) and phono. I personally seem to have a problem with phono. I have gone through the diaagnostics and have determined it is within the unit. It now is being serviced ( it needed it any way, just because of age).
    Bottom line is, I am thrilled with the sound of my various sources going through the CM III and coming out of the KEK LS 50s
    For what’s it worth
    Lou
     
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  14. cryanhorner

    cryanhorner Active Member

    Location:
    Portland, OR
    hey all, i'm interested in trying some new tubes in my cronus, but i don't want to just blindly replace everything and waste money. i understand the 4 large tubes (KT-120) are for the power amp, those seem more than fine. there are 5 smaller tubes (2) 12AX7, (3) 12AU7, can someone clarify what each of these do so i know where to focus my attention? thanks for your assistance.
     
  15. bajaed

    bajaed Forum Resident Thread Starter

    Location:
    USA
    The center 12au7 will be the key tube to roll. What do you have now and what kind of changes are you looking for?
     
  16. cryanhorner

    cryanhorner Active Member

    Location:
    Portland, OR
    at the moment i just have the stock tubes all around, so the 4 tung-sol kt-120s in the back and the 5 JJ's up front.

    i like the sound now, but i'm interested to see if i can improve it even further. i was looking at ECC801S Telefunken <> diamond / 12AT7 as someone had mentioned that it was really good for clarity and detail.

    does that tube work in the center slot? was trying to figure out if 12AT7 is compatible with 12AU7 to swap.

    what do the other 4 small tubes do?

    thanks for your assistance, i'm excited to try out some new tubes.
     
  17. Louis Grignon

    Louis Grignon Active Member

    Location:
    Montauk, NY
    has anyone done any comparisons of tube temp? I don't know if I am over analyzing this but in checking the kt 120 tubes on the new CMIII I find 3 of the the 4 have temps within a few degrees of each other. The 4th tube is off by 50-60 degrees or =/- 20%. I have checked the bias and all are at spec (35). Any opinions? would this affect the sound? All the smaller tubes are consistent in temps
     
  18. Helom

    Helom Forum member

    Location:
    U.S.
    You could swap the tubes around to see if it follows the tube - my bet is it will. Might want to turn down the bias some first.
     
  19. Louis Grignon

    Louis Grignon Active Member

    Location:
    Montauk, NY
    How does bias affect temperature? What is adjusting the bias doing?

    Thanks
     
  20. KT88

    KT88 Senior Member

    They use KT120 tubes. The KT120 is essentially a drop-in replacement for the KT88. It has better specs, ie more power, longer life in the same amplifier under the same conditions, wider bandwidth at lower distortion. The KT150 is much more expensive and requires a different set of transformers in most amps as well as different circuitry.
    -Bill
     
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  21. KT88

    KT88 Senior Member

    It controls current draw, so it is directly related to plate temperature. Since tubes are hand built, each tube has a bit of a different set of current paths and so some amplifiers, such as the Rogue Audio units, offer individual bias control for each tube. Since different components of tubes can have more or less current draw, the bias adjustment cannot effect them all equally, just proportionally. It's way better than having no control though! You basically set it low enough to satisfy whatever tube it is feeding. In an amp that only has one bias control for the entire tube set, you need to have matched tubes and you then set the bias for a comfortable range for the weakest of the tubes. You have to measure them individually to do that. rogue makes it easy by proving the built-in meter. For most consistent results and peace of mind, I always install and supply matched tube sets when I retube an amp for myself or anyone else.
    -Bill
     
  22. Louis Grignon

    Louis Grignon Active Member

    Location:
    Montauk, NY

    Thanks Bill,

    Compared to my old amp the Rogue CM3 sounds magnifcent. I can understand different (but the same) components operating at different temps. I install and maintain marine diesel engines. We are always checking heat sources and sinks. Withe the added elecrtronics running the engine voltage and temp can play a huge part in the running and life expectancy of the units.
    If I read your instructions correctly turning the bias down will drive the temp up?
     
  23. Louis Grignon

    Louis Grignon Active Member

    Location:
    Montauk, NY
    I gotta start using the speeling ck key
     
  24. Helom

    Helom Forum member

    Location:
    U.S.
    I suggested you first turn the bias down before swapping the tubes, so that each will be at a safe level when you install them in a different order.

    This was suggested to help you troubleshoot whether the temp difference follows the tube, regardless of socket position. I know the tubes are numbered to corresponding sockets from the factory, but that's only because they biased them at the factory - so each will be at a safe operating level at install.
     
  25. KT88

    KT88 Senior Member

    You are most welcome. Turning the bias controls clockwise reduces current flow, as indicated by the built-in current meter. Reducing current flow reduces heat.
    -Bill
     
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