New Tung-Sol KT120 output tube

Discussion in 'Tube Audio' started by Bob01605, Mar 25, 2010.

  1. Bob01605

    Bob01605 Member

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    [​IMG]

    Mike Matthews of New Sensor has just announced that New Sensor will be carrying the new Tung-Sol KT120 output tube. These new tubes are plug compatible with KT88 and 6550 tubes and may be used in any application that uses KT88 or 6550 tubes. As I write this these tubes are not as yet officially on the New Sensor web site. Look for a retail price of about $50 - $65 per tube or maybe even a little more. In an Email sent to dealers he stated ...

    "In September of 1950 Tung-Sol introduced the 5881, an uprated and industrial version of the 6L6GA with a 23.5 watt plate dissipation, opening the doors to the hi-fi movement of the 1950s. This rugged tube also found a home in the '59 Fender Bassman and servo amplifiers used in B-52 bombers. In 1955 Tung-Sol raised the bar of high fidelity with the introduction of the 35 watt 6550, which could deliver 100 watts with a pair in push-pull configuration. This tube was used in the Dynaco Mark III and Sunn amplifers.

    New Sensor now announces the Tung-Sol KT120, which has a plate dissipation of 60 watts, making it the most powerful tube in the 6550/KT88/KT90 family. A pair of these tubes in push-pull configuration can deliver power levels of 150 or more watts. When used at the parameters found in existing 6550/KT88/KT90 circuits, the Tung-Sol KT120 is impervious to overload, delivering peak power with extreme reliability and long tube life. However, taking advantage of the higher current handling capacity of these tubes, a very unique and super powerful and stable amp can be designed using the Tung-Sol KT-120."


    Tube specifications > http://www.newsensor.com/releases/KT120TungSol.pdf

    Tube curves > http://www.newsensor.com/releases/KT120TungSol-Curves.pdf

    Bob Latino
     
  2. bricktop

    bricktop Couch woofer

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    Neat! I hope this isn't one of those things that never develops or has quality issues and fades away.
     
  3. hhibrownsbac

    hhibrownsbac Super Member

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    Bob I was thinking about pulling the trigger on one of your ST120s, any chance of you attempting a model with these in it instead of the KT88s, or is it too early to even think that far in advance?
     
  4. tshoejohn

    tshoejohn Super Member

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    Cool! Hope it works out.
     
  5. DanO55

    DanO55 Radar - BSFR

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    WOW, just WOW!
     
  6. JHoman

    JHoman Tubes & Klipsch!

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    Ok Bob, can my Latino ST120 handle these? :lurk:

    Jeff
     
  7. thevic24

    thevic24 deep in sound thought

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    Iam thinking the same thing!! :scratch2:


    -Vic
     
  8. JHoman

    JHoman Tubes & Klipsch!

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    Vic, I posted the same question on the Dynaco forum, we will soon have an answer!:D
     
  9. thevic24

    thevic24 deep in sound thought

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    I just shot Bob an E-mail.

    Question, what tubes are you currently using in your ST120?

    -Vic
     
  10. thevic24

    thevic24 deep in sound thought

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    Actually on the Dynaco forum, he he says that it should work in the 120.





    -Vic
     
  11. thevic24

    thevic24 deep in sound thought

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    Bob just sent me this,




    Hi Vic,

    I don't believe that the KT120 tubes are actually available right now. They should work just fine in the ST-120. When they do become available I am going to order a set for my own ST-120.



    They look quite a bit larger then the KT88/6550's. I hope they clear the out put tranny's.

    -Vic
     
  12. JHoman

    JHoman Tubes & Klipsch!

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    When I got mine from Craig at NOS Valves, he recomended the Ruby KT88s, also running a Ruby rectifier, keep the copper cap as a back up. Running Mullard 4024s in the front end.

    What about you?
     
  13. JHoman

    JHoman Tubes & Klipsch!

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    What would we benefit from going from the KT88s to the KT120s?
     
  14. thevic24

    thevic24 deep in sound thought

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    IIRC, Bob told me the OPT's in the ST120 are good for around 80 wpc full band width.

    I would think the head room would almost double and we may gain a few more wpc.


    I was running EH6550's but one went out with a really bright flash:pity:.

    They sounded great but now I have the Sovtek KT88's that came with the amp.
    Iam using NOS Jan Philips 12AT7's in the board and a NOS Philips fat boy GZ34.

    I swear I can tell no power loss in triode so I have been using the amp in full time triode.

    I will be having a quad of GL KT88's coming soon from Jim McShane.


    -Vic
     
  15. JHoman

    JHoman Tubes & Klipsch!

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    I usually use it in Triode, I can't tell much difference. No difference in power through my Cornwall's.

    I'll wait and see what Bob thinks when he gets his KT120s.

    Craig told me that sonicly you don't get a tremendous difference from the power tubes, he said most of the difference is in the front end.
     
  16. Wavebourn

    Wavebourn New Member

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    11
    Good marketing idea: the same pinout like 1935'th 6L6, where 2'nd leg (filament) is near the 3'rd one (Anode!)

    I'm still waiting for mine (pls. see attachment)...
     

    Attached Files:

  17. bricktop

    bricktop Couch woofer

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    Yea, probably not the best of a pinout arrangement if high voltages are wanted. I suppose it was originally not a concern where the first 6L6s were concerned, where it was about 400 VDC max voltage. But, I can understand the desire to keep it standard so most people will just buy them and place them in their existing equipment. With the new KT120 supposedly handling 800VDC, maybe this might become an issue if run that high, although I've run with ~700VDC on EL34s without a problem.
     
  18. Matt The Cat

    Matt The Cat Prowlin' At 78 RPMs

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    I'm really interested to know how those KT120s will work/sound in McIntosh amps? I mean what will it do to a Mac MC275, which already gets around 90 watts per channel out of current KT88s? I wonder if the KT120s will mess up the circuit? Needless to say, I'm anxious to find out what their "deal" is as soon as people begin to test and try them?

    This is exciting news.

    -Matt
     
  19. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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    Seems to work OK for the current heavyweights in the family - EL34, 6L6GC, KT88, 6550, etc. If they changed the pinout now, people would probably end up burning up tubes or gear by plugging them into a socket with the old pinout.
     
  20. Wavebourn

    Wavebourn New Member

    Messages:
    11
    Right, now people are going to end up burning up their houses...

    They specified low first grid leak resistance needed. That means, in existing amps bias voltage will run away causing overheated anode; cheap anode material produces gases, they increase control grid current, and so on: red anodes, fire alarm, insurance, court trial, etc...

    If you put it into existing amp it will melt down or / and damage your amp. A first, grid leak resistor has higher value than 51K max specified for KT-120, and power transformer may be not so strong to power new filaments.
    As I said before, pin compatible tube non-compatible electrically means a marketing trick.

    Edit: at least, you can't sue the manufacturer: they are covered by requirements in datasheet about low value of a control grid resistor.
     
    Last edited: Mar 29, 2010

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