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    KT120 in VTA-70

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    mazeeff

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    KT120 in VTA-70

    Post by mazeeff on Thu Sep 17, 2015 2:08 pm

    Way back in 2010, I see where Bob indicated that the KT120 could be used in a ST-70 amp with upgraded power supply. My searches could yield no example of anyone who has tried this? What are the thoughts on this?

    Mike

    sKiZo

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    Join date : 2013-04-01
    Location : Michigan USA

    Re: KT120 in VTA-70

    Post by sKiZo on Thu Sep 17, 2015 3:02 pm

    Good post ... be interested myself.

    I imagine the stumbling block for most would be the requirement to upgrade the iron. Simple enough swap, but not cheap.

    I'd also highly recommend going with the "yellow sheet" mod on the rectifier socket, as well as a more robust rectifier. I can tell you from experience, a 5AR4 just ain't gonna cut it.

    Anybody I've heard though tends to like the tubes, so I'd think it'd be worth the effort. I love mine ...

    PS ... another option might be the TAD KT88STR's ... I got a set of those for backup, and I'd say they're a very close match to the sound of the KT120's. Heavy glass and structure similar to the vaunted old school British MOVs and GLs. Nice response all the way, and very tight bottom ... and mine ain't really broken in. A matched quad will cost a bit more, but cheaper in the long run as you can run them with the stock iron.

    corndog71

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    Re: KT120 in VTA-70

    Post by corndog71 on Thu Sep 17, 2015 3:03 pm

    The KT120 is NOT recommended for the VTA70. They can be used in the VTA120 with no problem.

    sKiZo

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    Join date : 2013-04-01
    Location : Michigan USA

    Re: KT120 in VTA-70

    Post by sKiZo on Thu Sep 17, 2015 3:09 pm

    Huh ... I seem to remember Bob saying something about them being ok with an iron upgrade, but you know the innernet ... it lies ...

    Thanx for the nudge though. I just swapped the TAD's back in, and they're warming up as we speak. Get some more hours on them and see if they still sound as good as I remember ...

    Oh. Friendly reminder. DO retension your sockets and rebias after any tube swap! Pin sizes can be slightly different, and they all bias up a bit different.

    mazeeff

    Posts : 114
    Join date : 2014-01-06
    Age : 61
    Location : Grand Rapids, Michigan, USA

    Re: KT120 in VTA-70

    Post by mazeeff on Thu Sep 17, 2015 3:15 pm


    peterh

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    Location : gothenburg, sweden

    Re: KT120 in VTA-70

    Post by peterh on Thu Sep 17, 2015 3:24 pm

    6550 / kt88 works fine in vta70. I have been running JJ/6550 for 900h now

    corndog71

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    Re: KT120 in VTA-70

    Post by corndog71 on Thu Sep 17, 2015 4:22 pm



    Yes, he did write that. I stand corrected. Although all of his tests were on the VTA120.

    Bob Latino
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    Re: KT120 in VTA-70

    Post by Bob Latino on Thu Sep 17, 2015 5:05 pm

    I said at that time (5+ years ago) you could use the Tung-Sol KT120's in an ST-70 with an upgraded power transformer. IMHO though > If you have a VTA ST-70 you should probably stick with EL34, 6L6, KT66, KT77, KT88 and 6550 output tubes. KT120 output tubes draw even a little more current than KT88's and even the upgraded power transformer in the VTA version of the ST-70 will be run harder. I mean why push your luck ? There are many fine versions of the 6 tubes mentioned earlier in this paragraph that you can use in the VTA ST-70. With that said > The KT120 IS perfectly fine to use in the VTA ST-120 and/or VTA M-125 monoblocks ..

    Bob

    mazeeff

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    Re: KT120 in VTA-70

    Post by mazeeff on Thu Sep 17, 2015 5:28 pm

    Thanks Bob. Good advice.

    kaner

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    Join date : 2011-09-20

    Re: KT120 in VTA-70

    Post by kaner on Fri Sep 18, 2015 11:10 pm

    So this leads to the obvious next question. Has anyone rolled these tubes through their ST70? What are your impressions? 6L6's can be had for a fairly reasonable price. Is it worth getting a quad?

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