Rogue Cronus Magnum III

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

  1. Conezays

    Conezays Forum Resident

    Location:
    Canada
    When the issue occurs, tapping anywhere on the amp/near its vicinity resulted in loud hum/variance. Going to mess around to try to isolate the issue further. It's a long process trying different configurations (powering down, unplugging, reseating the tubes, etc.) and then still dealing with issue upon powering back on. Furthering my confusion, if I was doing a poor job seating the tubes for weeks with different combinations, why did it only result in noise issues this past week?

    Knock on wood, haven't had the issue since putting the new KT120's back in but I imagine I'll eat my words soon enough.

    Will give that thread a read, thanks! I think my NOS tube experience has put my partner off of them more than me :p

    [​IMG]
     
  2. Conezays

    Conezays Forum Resident

    Location:
    Canada
    Nope, lasted 30 minutes being quiet until I heard a repeating tapping sound. Sigh. May have to bug my local shop to give this is a look so I can at least rule out if I am the issue, lol.
     
    Last edited: Aug 30, 2020
  3. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    do you have any spare tubes? can you isolate it to a specific tube? try tapping on the small signal tubes.
     
  4. Conezays

    Conezays Forum Resident

    Location:
    Canada
    I could produce a temporary hum by tapping the small signal tubes, but I couldn't get rid of the repeating tapping (hadn't heard the tapping before this bootup).

    I have my stock JJ's still which I could put back in the amp, which was probably going to be my next step if I can muster enthusiasm.
     
  5. Conezays

    Conezays Forum Resident

    Location:
    Canada
    Sadly, it does seem to appear that the Brimar 12AU7 is noisy. I swapped it out for the Radiotechnique and haven't been able to replicate the noise issues after 2 days of straight listening. Disappointed that I can't use the Brimar (loved the sound with the other tubes), but glad to know I'm not completely crazy! Doesn't appear I have much recourse with getting a refund on tubes from this store though.

    Sound-wise, the Radiotechnique comes off a little brash and bright when used with the GE 12AX7's and RCA 12Au7's. It still sounds *good*, but the overall sound veers toward a little too trebly for my liking (while simultaneously sounding overly bassy with uncontrolled lows. Kind of hard to articulate). I didn't find the issue as egregious when I paired it with JJ 12AX7s, so something for me to consider further with nailing down which tubes to use.

    Relatedly, the D5 arrived so I may clean all of the tube contacts later in the week and try again with other tube combinations.
     
    Last edited: Sep 1, 2020
    avanti1960 likes this.
  6. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    better a tube than the amp!
     
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  7. Conezays

    Conezays Forum Resident

    Location:
    Canada
    I think you may have jinxed me :p Lasted a few days using different tubes without issues before they cropped up again, along with some new ones (!) like the speakers making loud popping sounds intermittently. Going to have my local store take a look at it.
     
  8. GreenLeafRustler

    GreenLeafRustler Well-Known Member

    Location:
    Brentwood, TN.
    Had to send my CM III back to Rogue. I fired it up Friday evening of Labor Day weekend and a white flame shot through the V4 power tube slot. At first, they were skeptical that I hadn't simply blown a power tube, but I knew it was a far more serious problem than that.
    Turns out it had a circuit trace issue on the PCB board and had to be replaced. They also stated I have a very early SN# , so they upgraded a few tweaks that are now standard on the CMIII's.
    They didn't elaborate on what those changes included. Most fortunately, all my NOS tubes tested fine. Overall, a good customer service experience. 100% warranty work repair. $108 UPS ground freight from Nashville to them; $50 UPS ground freight for the return. Due back today.
     
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  9. GreenLeafRustler

    GreenLeafRustler Well-Known Member

    Location:
    Brentwood, TN.
    I don't know if i just missed having it, or if Rogue did something that significantly improved the sound. But, goodness... my personal reference jazz LP is Sonny Clark's Cool Stuttin'.
    Every player is "tighter" , immediate, just hanging in space. It's sublime. Enjoy the weekend.
     
  10. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    when i had my CM II the soundstge of the sonny clark record was huge !
     
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  11. Slippers-on

    Slippers-on Forum Resident

    Location:
    St.Louis Mo.
    Cool Struttin! You betcha!
    If you don't have any, look for some of those Art Farmer reissues he did with Joe Pass!
     
  12. GreenLeafRustler

    GreenLeafRustler Well-Known Member

    Location:
    Brentwood, TN.
    Thank you Avanti1960, I've been reading your tube recs for years, and you're dead on similar to my ears. I'm looking forward to swapping my Mullard center for an Amperex. I think I'll like the presentation... And THANK YOU , slippers-on, this record introduced me to Art Farmer. I'll be on the look out!

    Cool Struttin' is just terriffic... for rim thwacks and the bass lines alone. -
     
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  13. avanti1960

    avanti1960 Forum Resident

    Location:
    Chicago metro, USA
    Thanks GLR !
    please censor yourself whenever you mention A^%$#x tubes! They are nearly extinct ! :)
     
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  14. Conezays

    Conezays Forum Resident

    Location:
    Canada
    Yikes, glad to hear everything worked out for you in the end. Definitely frustrating, I'm sure.

    With regards to my own CMIII updates, my amp is still in the shop. The store has experienced all of the issues I mentioned, so at least I'm not totally crazy. Their best guess is I got a batch of bad tubes, as they can't recreate the issues with the stock JJs. The odds of multiple theoretically tested tubes from reputable stores, etc. all being bad sounds very unlikely to me, but not out of keeping with my luck at times! :laugh:
     
  15. GreenLeafRustler

    GreenLeafRustler Well-Known Member

    Location:
    Brentwood, TN.
    Any luck with the repair Conezays?
     
  16. Conezays

    Conezays Forum Resident

    Location:
    Canada
    Thanks for asking. The store was fairly baffled as to what the exact issues were, but ultimately they seemed to think it was the fault of the tube(s)-likely the Brimar 12AU7. The store experienced all of the same issues I did, but after reseating the tubes and inspecting the amp further claimed that the issues did not reoccur. They never experienced any issues just using stock JJ's with the amp, for what it's worth.

    I took the amp home and it sounded great. However, I noticed the right 12AX7 was sticking out higher and hadn't been seated properly (not 100 % sure if it somehow jiggled around when moving it or it was like that at the store). The next day I began to notice a light tapping-like sound in the right channel (very different than the prior loud microphonic sound). I reseated the 12AX7 and haven't experienced issues since, knock on wood. It's only been a few days so I'm not ready to celebrate just yet, but glad that it appears to be a tube, and not an amp, issue. The tube combination sounds fantastic and much better than the stock JJs so I don't really want to revert to them unless I absolutely have to :p
     
  17. Conezays

    Conezays Forum Resident

    Location:
    Canada
    As an update, I swapped out the Brimar (continued to have weird sounds) for a Blackburn Mullard 12AU7 in the centre position. Been smooth sailing since and it sounds great.
     
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  18. Megamoz

    Megamoz Member

    Location:
    Italy
    Hello,

    I have recently moved into a new place. Before that, when I was packing my CM III, I heard a sound of a loose screw inside the device. As I moved the amp the screw slid from one side to the other. Since I didn’t have time to see what it was in, I decided to open the amp later. And when I was taking the amp out of its box, a small screw fell off on ground. You can find the photo of it in the link. Do you have any idea of where it belongs?

    Thanks for your answers.

    CM III

    [​IMG]
     

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