Power Tube Help!

hochpt21hochpt21 Posts: 5,035
If you had a tube amp with 4 KT120’s with around 200 hours, and one of them broke...what would you do and why?

Replace the broken one?
Replace a pair? (And what position)
Replace the quad?

Thanks,
Paul
__________________________________________________
2 Channel
Turntable - VPI Scout 1.1/Ortofon 2M Blue
Integrated Amplifier - Rogue Audio Cronus Magnum II
Speakers - GoldenEar Triton 2
__________________________________________________
7.1 Home Theater
Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
__________________________________________________
Man Cave
Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
__________________________________________________

Comments

  • pitdogg2pitdogg2 Posts: 10,567
    I'd check bias. 200 hours is not a lot of time to be honest.
  • kharp1kharp1 Posts: 2,464
    I agree that 200 hrs is nothing time wise, but, a tube can go south for any number of reasons. I prefer to replace a pair and keep the odd one for backup.
    Main System:
    Joule-Electra LA 100 MKIII
    Pass Labs Aleph 30, McCormack DNA-125, Parasound A21
    Marantz SA-14S1
    Usher CP-6311/Tyler Acoustics Taylo Reference Monitor, LSA-1
    Dual SVS SB2000
    Wireworld Equinox 7 bi-wire, Wireworld Silver Eclipse 7 IC

    Secondary Rig:
    Parasound P5, Audio Electronics by Cary Constellation
    Marsh a200s, Audio Elecrtonics by Cary Hercules
    Pioneer Elite DV-45a, Denon DVD-2910
    Klipsch Epic CF-1, Vandersteen 3CE sig
    Analysus Plus Oval

  • michaeljhsda2michaeljhsda2 Posts: 1,848
    Just replace the one bad tube. Re bias all four after it's installed
    SDA SRS 1.2TL's w/ RD0198-1's, Sonicap, Mills
    AI-1 Dreadnought
    SDA 1C's w/Clarity Cap ESA; PA, Mills, RD0194-1's
    SDA 1C's stock
    SDA 2B TL's w/RD0198-1's
    SDA 2's (side by side tweeters) stock
    Yaqin MC-30L integrated tube amp
    Yaqin MS-20L integrated tube amp
  • hochpt21hochpt21 Posts: 5,035
    I should have clarified. Tube was damaged during shipping. Nickle sized circle-ish crack...
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • hochpt21hochpt21 Posts: 5,035
    Just replace the one bad tube. Re bias all four after it's installed

    That would be ideal. So even with different hours, as long as the bias is checked every few months I should be good?
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • hochpt21hochpt21 Posts: 5,035
    kharp1 wrote: »
    I agree that 200 hrs is nothing time wise, but, a tube can go south for any number of reasons. I prefer to replace a pair and keep the odd one for backup.

    If I replaced a pair, does it matter what position they go in relative to the other ones?
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • mhardy6647mhardy6647 Posts: 18,762
    Probably. No idea what the amp's topology is, but if it is stereo(?) then there should be two push-pull pairs. The push and pull halves of one channel should be as identical as possible (in the best case). This is critical if the bias cannot be adjusted (as was often the case in many, even very fine, vintage amplifiers.

    If it's a monoblock with four tubes, it's probably push pull parallel.

    In either case, if the bias can be adjusted for each tube individually, it's less of a factor than it would be in a fixed bias amplifier with no adjustment. Note, "fixed bias" simply means that there's a bias supply circuit (as opposed to, e.g., "cathode bias" in which the tube itself is actively involved in the bias circuit). A "fixed bias" amp can have adjustable bias, and nowadays many do! :)
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • pitdogg2pitdogg2 Posts: 10,567
    hochpt21 wrote: »
    I should have clarified. Tube was damaged during shipping. Nickle sized circle-ish crack...

    With this "new" info I'd say you may be replacing more sooner than later if it was rough handling. I'd find a pair.
  • hochpt21hochpt21 Posts: 5,035
    mhardy6647 wrote: »
    Probably. No idea what the amp's topology is, but if it is stereo(?) then there should be two push-pull pairs. The push and pull halves of one channel should be as identical as possible (in the best case). This is critical if the bias cannot be adjusted (as was often the case in many, even very fine, vintage amplifiers.

    If it's a monoblock with four tubes, it's probably push pull parallel.

    In either case, if the bias can be adjusted for each tube individually, it's less of a factor than it would be in a fixed bias amplifier with no adjustment. Note, "fixed bias" simply means that there's a bias supply circuit (as opposed to, e.g., "cathode bias" in which the tube itself is actively involved in the bias circuit). A "fixed bias" amp can have adjustable bias, and nowadays many do! :)

    Just changed my sig...Rogue Audio Cronus integrated amp. Bias is individual.
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • michaeljhsda2michaeljhsda2 Posts: 1,848
    hochpt21 wrote: »
    Just replace the one bad tube. Re bias all four after it's installed

    That would be ideal. So even with different hours, as long as the bias is checked every few months I should be good?

    Definitely
    SDA SRS 1.2TL's w/ RD0198-1's, Sonicap, Mills
    AI-1 Dreadnought
    SDA 1C's w/Clarity Cap ESA; PA, Mills, RD0194-1's
    SDA 1C's stock
    SDA 2B TL's w/RD0198-1's
    SDA 2's (side by side tweeters) stock
    Yaqin MC-30L integrated tube amp
    Yaqin MS-20L integrated tube amp
  • hochpt21hochpt21 Posts: 5,035
    edited July 9
    Just purchased a pair, and will keep one for back up.

    Does it matter what position I install them in?

    cpbgaj3gpy07.png
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • hochpt21hochpt21 Posts: 5,035
    edited July 9
    .
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • michaeljhsda2michaeljhsda2 Posts: 1,848
    hochpt21 wrote: »
    Just purchased a pair, and will keep one for back up.

    Does it matter what position I install them in?

    cpbgaj3gpy07.png

    No
    SDA SRS 1.2TL's w/ RD0198-1's, Sonicap, Mills
    AI-1 Dreadnought
    SDA 1C's w/Clarity Cap ESA; PA, Mills, RD0194-1's
    SDA 1C's stock
    SDA 2B TL's w/RD0198-1's
    SDA 2's (side by side tweeters) stock
    Yaqin MC-30L integrated tube amp
    Yaqin MS-20L integrated tube amp
  • hochpt21hochpt21 Posts: 5,035
    hochpt21 wrote: »
    Just purchased a pair, and will keep one for back up.

    Does it matter what position I install them in?

    cpbgaj3gpy07.png

    No

    Perfect, thank you.
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • hochpt21hochpt21 Posts: 5,035
    Got her up and running. Changed power tubes in 1 and 4. Bias set.

    Sounds beautiful.
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
  • jumpindickjumpindick Posts: 208
    If you ever want to roll tubes, the one in the middle (preamp) tube is that one to change. That is the one that has max impact on the overall sound coming out of that amp. I tried a few of them, but the best one, for me at least, was Psvane 12AU7 which is what you got..
  • nooshinjohnnooshinjohn Posts: 18,056
    The folks a Rogue would have replaced the damaged tube for free. I just lost a power tube on one of my amps, and after 7 years of faithful service, I am getting ready to replace all 12 KT120's.
    The Gear... Carver "Statement" Mono-blocks, TriangleArt Reference SE with PS Audio NuWave Phono converter, Walker Precision Motor Drive, ClearAudio Stradivari v2 cartridge and Origin Conquerer Mk3c tonearm, Polk Audio "Signature" Reference Series 1.2TL with complete mods, Pass Labs X1 two channel preamplifier Signed by Poppa himself, PS Audio PerfectWave DAC MkII, Krell Evolution 525a CD Player, Pioneer Elite SC-65, Oppo UDP-205 Blu-ray , Sony XBR70x850B 4k, Polk audio AB700/800 "in-wall" surrounds

  • hochpt21hochpt21 Posts: 5,035
    I have a few tubes coming from @heiney9 , but the Psvanes sound pretty exceptional in there right now.
    __________________________________________________
    2 Channel
    Turntable - VPI Scout 1.1/Ortofon 2M Blue
    Integrated Amplifier - Rogue Audio Cronus Magnum II
    Speakers - GoldenEar Triton 2
    __________________________________________________
    7.1 Home Theater
    Denon AVR-X3300W; Rotel RMB-1066; Polk CS350ls, LS90's, FXi3's, RC60i; SVS PC Ultra; BenQ W1070; Elite Screens 120"
    __________________________________________________
    Man Cave
    Turntable - 1) Pro-Ject 2.9 Wood/Grado Gold; 2) Sony PS LX410/Grado Green
    Phono Stage - PS Audio GCPH, Parks Audio Budgie; CD - Marantz DV4001
    Preamp - Dared SL2000a, Luminous Audio Axiom II; Amplifier - Parasound HCA-1500A
    Speakers - SDA 2A (x-overs etc...); Epos Epic 2; Polk Audio Monitor 70 (my first)
    __________________________________________________
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