Bias question on a Rogue Cronus Magnum 2

hochpt21
hochpt21 Posts: 5,423
in 2 Channel Audio
I checked the bias the other day, following the instructions from the manual.

Three tubes went perfectly.

On one, however, when I flipped the bias switch the meter jumped up like it was supposed to. I went to adjust it like the other three, but when I used the tool to turn the tiny screw...the meter didn't move at all. The meter is supposed to move when I adjust the screw. When I flipped the switch back the other way the meter went to zero.

I tried it a couple times and same thing on that one tube. I could turn the screw all I wanted back and forth, but the meter didn't move. Audio sounds fine, so I'm not sure whats going on. Is it the fuse? Is that screw stripped?

Thanks in advance for any advice!

Paul
2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • mikeyb128
    mikeyb128 Posts: 2,885
    I would Contact rogue. I emailed them a question regarding my stereo 100 and I had a reply in about 2 hours.
    2 channel:
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    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

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  • Faustin
    Faustin Posts: 1,149
    ^^^This^^^
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  • hochpt21
    hochpt21 Posts: 5,423
    Good thought. I will do that.
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • hochpt21
    hochpt21 Posts: 5,423
    Just a quick update, Rogue was great with e-mail communication and I ended up sending the unit it. Haven't heard anything back yet, and Monday will be two weeks, so I'll probably check in then. I'm sure it is very busy around the holidays.

    I'll update when I hear from Rogue on what the actual issue is and the solution.
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • erniejade
    erniejade Posts: 6,321
    edited December 2018
    Sounds like solid customer service.
    Klipsch The Nines, Audioquest Thunderbird Interconnect, Innuos Zen MK3 W4S recovery, Revolution Audio Labs USB & Ethernet, Border Patrol SE-I, Audioquest Niagara 5000 & Thunder, Cullen Crossover II PC's.
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  • hochpt21
    hochpt21 Posts: 5,423
    This was the diagnosis.

    The output tubes in your amplifier are the correct brand and tube type, but it appears that some of the specs of this tube set are not ideal for use in the Cronus Magnum. They do operate fine, but having a high plate current rating may result in the tubes blowing fuses occasionally and it is also the reason why the bias will not adjust below 30-35mA on any of the 4 tubes

    I have the Tung Sol 120's. Two I believe are stock and two I purchased after to replace a broken one.

    Can someone help me out? They said my tubes are not bad, but will not bias correctly because of a high plate current rating in them. They said my tubes will work, but may blow fuses occasionally.

    They offered the option of purchasing a quad of the same tubes.

    Does that mean my tubes actually are bad? Or are there different specs in the same exact tube of new production tubes.

    I don't want to spend the $ on a new quad if I don't need it. But will if I do.

    Help!
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • mikeyb128
    mikeyb128 Posts: 2,885
    edited December 2018
    I would buy their tubes, which are fully tested and burned in with your amp. Maybe shoot over to YouTube and watch some videos on kt120 by kevin deal. He explains the importance of a thorough screening process with these new production tubes.

    “They do operate fine, but having a high plate current rating”

    ^^^ this doesn’t sound like tubes that are still ok. They may play “fine” but blow fuses....
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

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  • hochpt21
    hochpt21 Posts: 5,423
    mikeyb128 wrote: »
    I would buy their tubes, which are fully tested and burned in with your amp. Maybe shoot over to YouTube and watch some videos on kt120 by kevin deal. He explains the importance of a thorough screening process with these new production tubes.

    “They do operate fine, but having a high plate current rating”

    ^^^ this doesn’t sound like tubes that are still ok. They may play “fine” but blow fuses....

    Thanks for the input.

    I replied with a message asking about the plate current rating on any tubes I purchased through them and if there was a warranty of any kind. They said the tubes they use have a low iP rating so there would be no bias issues. 90 day warranty.
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • delkal
    delkal Posts: 764
    edited December 2018
    I don't like the sound of this. Everyone knows tubes do not have the consistency of solid state components and their microohm output does vary (even between 2 new tubes, same brand, and made the same day............

    But all tubes have specs that should be designed for. Sounds like Rogue based their design on some lower output KT-120's (probably Chinese made) they had lying around. But all KT-120's should work. Sounds like a design flaw.

    Now they want you to buy their one brand of tubes so their amp works? BS! You don't buy tube amps if you can't tube roll.
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  • hochpt21
    hochpt21 Posts: 5,423
    Yes, I was a little unsure of the whole situation, but went with the recommendation of new tubes.
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • mikeyb128
    mikeyb128 Posts: 2,885
    edited December 2018
    delkal wrote: »
    I don't like the sound of this. Everyone knows tubes do not have the consistency of solid state components and their microohm output does vary (even between 2 new tubes, same brand, and made the same day............

    But all tubes have specs that should be designed for. Sounds like Rogue based their design on some lower output KT-120's (probably Chinese made) they had lying around. But all KT-120's should work. Sounds like a design flaw.

    Now they want you to buy their one brand of tubes so their amp works? BS! You don't buy tube amps if you can't tube roll.

    There is only one brand of KT120. Only made in Russia by Tung Sol. There is no Chinese KT 120, there is no other brands of KT 120 to roll. If you do your research you will find that some of these tubes have excessive plate voltages that some amps are sensitive to. Maybe his amp is one of those? Not quite a design flaw. Some tubes work great in some equipment and some don’t. I have had micrphonic tubes in some equipment but quiet as a mouse in others. That’s just the way it goes.

    The quality control in new production tubes can’t touch what it used to be. And if you do more research the Russian and Chinese manufacturers pump out tubes
    Like crazy. noises ones, ones that don’t meet specs etc... that’s why companies like rouge, upscale, the tube store test these tubes prior to selling them, that way you don’t have issues.
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

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  • pitdogg2
    pitdogg2 Posts: 25,441
    Yep true i seen a video on upscale about KT120 and 150's and they said theirs are more expensive because a lot of them do not pass muster and I believe he said there is no way for them to return them to the manufacturer as "defective" so they have to make up the money they're losing on tubes they refuse to sell you and be able to guarantee the good ones they do sell.
    I believe it was Kevin Deal in the video and showing how stringent they were with testing these power tubes not just once but many times before they went to be sold just so they can guarantee them.
    It's well known that Russia is all about putting out tubes not putting out quality tubes it's all on the number of tubes they put out. Do they put out some quality tubes of course they do they also put out tubes that they know are junk or near junk that's just the nature of the beast these days in making tubes just like Mikeyb is stating.
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  • dolsey01
    dolsey01 Posts: 15
    Had High IP tubes cause problems in my Rogue 88. Talked to Nick at Rogue and he told me to use tubes below IP of 59. The factory tubes were in the 30s. I had my tube vendor pick a quad in the 30s and it was solid as a rock after that.
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  • heiney9
    heiney9 Posts: 25,165
    Check with Jim McShane. He's honest and knowledgeable about a lot of gear that uses New Stock tubes. Power tubes do vary a bit, but, IMO, the amp should be designed with enough tolerance to accept that variance unless it's way out.

    New Stock tubes do have their issues as consistency isn't like old stock tubes.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • hochpt21
    hochpt21 Posts: 5,423
    Yea, I was just trusting Rogue on this one. They said that my tubes have a high plate current rating, but when I asked them if there was an option (even for a charge) to test the tubes and put the results on the box (in case any of them didn't have issues, I could use them for back up), they said their tester only tests for shorts and emissions. Not plate current rating.

    Doesn't make sense to me, but I openly admit to not being well versed in the operations of tube amps, so I am going with their opinion on this one.
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • heiney9
    heiney9 Posts: 25,165
    Makes no sense for them to claim their tubes have lower plate current and then have no way to test for it. I wouldn't pay a lot of $$ for tubes that weren't thoroughly tested, especially since your amp (made by them) is a bit finicky with power tubes.

    I'd be leary, but just like any other manufacturer, they are out to make money. Possible they bent the truth a little bit. If that's what you feel comfortable with and you can sleep at night, then no one here can fault you.

    Next time check with Jim McShane, if for no other reason than to just get some knowledge. He's a straight shooter.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • delkal
    delkal Posts: 764
    hochpt21 wrote: »
    they said their tester only tests for shorts and emissions. Not plate current rating.

    An outfit like Rougue only has a simple Emission tube tester? That is hard to comprehend. I won't buy a tube off ebay if its not tested on a Mutual conductance tester that has a real readout in micoohms.

    I wouldn't buy tubes from them either. There is no way to match tubes with an emission tester. All they can tell is the heater works and they have no clue if the plate current of the tubes they sell you don't have the same problem!

    This will take a while to sink in. No wonder they couldn't get the design right.

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  • hochpt21
    hochpt21 Posts: 5,423
    One final follow up.

    They replied a final time and said the tube manufacturer puts the iP rating on the box and they only buy ones with a low rating.

    I have the unit back and it is singing sweetly. Was it a wanted expense? No. BUT, they checked the whole unit over while in the shop, and ideally I should be good for a long time with the new quad.

    It sounds good...
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
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  • erniejade
    erniejade Posts: 6,321
    Awesome!
    Klipsch The Nines, Audioquest Thunderbird Interconnect, Innuos Zen MK3 W4S recovery, Revolution Audio Labs USB & Ethernet, Border Patrol SE-I, Audioquest Niagara 5000 & Thunder, Cullen Crossover II PC's.
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  • vcwatkins
    vcwatkins Posts: 1,993
    I had very similar circumstances. I had problems with KT-120's - were blowing fuses and impossible to bias. Took into local shop that is a new Rogue dealer/service. Replaced the tubes and made a few other minor repairs. I've been fine since then - about a year.

    I had bought 4 tubes on eBay at a discount and used 2 of them. Dealer thinks - and I have no evidence to think otherwise - that the tubes were defective. Looked up the seller - "Hilliard I LLC", but I'm unable to see the listing or any current listings by Hilliard.
    b]Beach Audio[/b]: Rega RP6 (mods) - AT33PTG/II - Parks Budgie SUT - PSAudio NPC * Eversolo DMP-A6 * Topping D90iii * Joule-Electra LA-100 mkIII * Pass Aleph 30 * MIT S3 * Polk SRS 2.3tl (mods) * PSAudio PPP3
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  • delkal
    delkal Posts: 764
    edited December 2018
    All Rogue needed to do is change a couple resistors and the amp wouldn't have the plate current problem with higher output tubes. I am surprised they didn't offer you that option.

    But they would not be able to make their 100 watt wattage ratings with standard /mediocre tubes. This is all about marketing. No one will never hear any difference if an amp puts out 90-95-100 watt output at max.

    But it HAS to be 100.
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