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    Wondering about the KT120

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    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Wondering about the KT120

    Post by dougmon on Sat Apr 04, 2015 10:23 pm

    For the past few years, I've been running either a stock Dynaco ST-70 or a VTA-70. My tube of choice has been the EL34, which gives a slightly dark sound (relative to the KT88, which I've run in other amps over the years). But I really enjoy that sound. I find the KT88 to have great clarity, but to be sort of glassy-sounding, at least in the amps I've heard it in.

    So, while I've read a lot of "sounds great!" comments about the KT120, I've read no descriptions of how it might actually sound in, say, a VT-120.

    So, I have a very simple question which may lead to some complex answers. Does the KT120 lean more towards the KT88 sound, the EL34 sound, or does it have a combination of the two?

    Thanks.

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: Wondering about the KT120

    Post by MontanaWay on Sat Apr 04, 2015 10:35 pm

    I find the KT120 a very pleasing tube to listen to. It has a very good bass, but not over powering. At the same time, I also find extremely clear.
    I do not however, recommend the KT120 on an ST70. The KT120 will draw more current than the KT88 and EL34, the ST70 will run hotter and its power transformer will be pushed.

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Wondering about the KT120

    Post by dougmon on Sat Apr 04, 2015 10:40 pm

    MontanaWay wrote:I find the KT120 a very pleasing tube to listen to. It has a very good bass, but not over powering. At the same time, I also find extremely clear.
    I do not however, recommend the KT120 on an ST70. The KT120 will draw more current than the KT88 and EL34, the ST70 will run hotter and its power transformer will be pushed.

    Thanks, I wasn't actually thinking of running it on an ST-70 (or VTA-70, which is what I have now). I was thinking of going with the VTA 120 at some point.

    I should clarify. What I love about the EL34 is that wonderful midrange, and I was wondering: how much of that would I get in a VTA120 with ST120s?

    Thanks.

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: Wondering about the KT120

    Post by MontanaWay on Sat Apr 04, 2015 10:41 pm

    dougmon wrote:
    MontanaWay wrote:I find the KT120 a very pleasing tube to listen to. It has a very good bass, but not over powering. At the same time, I also find extremely clear.
    I do not however, recommend the KT120 on an ST70. The KT120 will draw more current than the KT88 and EL34, the ST70 will run hotter and its power transformer will be pushed.

    Thanks, I wasn't actually thinking of running it on an ST-70 (or VTA-70, which is what I have now). I was thinking of going with the VTA 120 at some point.

    I should clarify. What I love about the EL34 is that wonderful midrange, and I was wondering: how much of that would I get in a VTA120 with ST120s?

    Thanks.

    for my ears, the KT120's cover the whole range very well, but like I said, thats for my ears Very Happy

    camaroguy

    Posts : 11
    Join date : 2015-03-30

    Re: Wondering about the KT120

    Post by camaroguy on Sun Apr 05, 2015 5:21 pm

    I tried them in the Mark III's and liked them very much. When compared to EH6550's I'd say a bit more bass but tighter. Mids and highs seemed close, maybe a tad more upper end detail with the KT120's. I might add when I tried them I never removed them until I took the amps apart. camaroguy

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Wondering about the KT120

    Post by sKiZo on Sun Apr 05, 2015 9:32 pm

    Love them big trees!



    I also find them quite tasty ... as mentioned, strong bottom but no boom, and smooth up through the vocals and beyond.

    Big advantage is that you'll never push them all that hard in a VTA amp. You'll never see the rated output either ... they top out at around 8-10% over what you'd see with KT88's.

    Speaking of which, I gotta switch back to the KT120's again one of these days. I picked up on a quad of TAD KT88STR's a couple months back - actually more expensive than the KT120's, but I was looking for something different. Those are "copies" (whatever that means in this day and age) of the old Brit MOV's, right up to the heavy glass envelope. Real sweet, giving me the same tonal characteristics I got to love with the KT120's.

    If I had a complaint with the TAD's, it'd be that I've had them clip a time or two at the same settings I use for the KT120's, but I like it loud, and I use a sub synthesizer and expansion. That's where those extra watts come in handy. No biggie - a couple minor EQ tweaks and all's well once again.

    * Worth repeating, they do require a bit more beef than the ST70 can provide. The ST120 and monoblocks have a lot more iron and handle them with no complaint.

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Wondering about the KT120

    Post by dougmon on Mon Apr 06, 2015 10:31 pm

    Thanks, everyone. I think what I was asking was "In the spectrum between the KT88 and the EL34, where does the KT120 lie?" From these answers, it seems to me that it's closer to the KT88.

    TMadden

    Posts : 99
    Join date : 2011-12-22

    Re: Wondering about the KT120

    Post by TMadden on Wed Apr 08, 2015 5:35 pm

    I'm anxiously waiting for a quad of KT120's to arrive for use in  my M65's, monoblock versions of Bob's ST120.
    The M65's drive the main speakers in my home theater. I just changed them from Ascend Acoustic CMT-340's,
    which are quite efficient and had a nice flat 8 ohm impedance curve, to a Scan Speak design by  Troels Gravesen : www.troelsgravesen.dk/Ellam-dappo.htm . The impedance dips down to 3.3 ohms, I'm thinking the KT120's may be able to handle the load better than the
    KT90's I'm currently using. It's interesting that both speakers have impressively flat frequency response curves , yet the mid-range is much more articulate with the Scan Speak  drivers. The treble is far smoother with the ring radiators than it was with the 1" domes also. Never judge a speaker by it's curves! Anyway, the KT120's are due Friday, can't wait!!


    Last edited by TMadden on Wed Apr 08, 2015 5:44 pm; edited 2 times in total

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Wondering about the KT120

    Post by dougmon on Wed Apr 08, 2015 5:39 pm

    TMadden wrote:I'm anxiously waiting for a quad of KT120's to arrive for use in  my M65's, monoblock versions of Bob's ST120.

    Well, please report on what you think!

    TMadden

    Posts : 99
    Join date : 2011-12-22

    Re: Wondering about the KT120

    Post by TMadden on Fri Apr 10, 2015 11:33 am

    dougmon wrote:

    Well, please report on what you think!

    Listening to them now! Watching the movie Prometheus on Blu-Ray, pushing the volume to fairly "intense" levels.  Compared to the EI KT90's, I'm hearing more headroom, less strain at higher volumes (none really), and the higher frequencies are definitely cleaner, more open and detailed.
    Cant comment on the low end, crossover is set at about 130Hz. Very happy! Great tubes for my M65's!

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Wondering about the KT120

    Post by deepee99 on Fri Apr 10, 2015 7:15 pm

    I sure like my KT-120s. Unless thrown from a helicopter they're pretty sturdy. New Sensor is on to something here.
    The interaction between drivers and outputs is beyond my pay scale. My first-iteration drivers on the M-125s sounded much sweeter with antique TS 6550s than the new 120s. Now with the upgraded driver boards, I think the New Sensor 120s have the edge. Why that should be, I dunno, but there it is.
    Hey TMadden, put Amadeus on the Blu-Ray or DVR some time. Blow your mind.


    TMadden

    Posts : 99
    Join date : 2011-12-22

    Re: Wondering about the KT120

    Post by TMadden on Fri Apr 10, 2015 7:34 pm

    I'm using the CCS driver boards, the noval version, not the octal. I just happen to have a set of the octal version, may have to try them. Also pondering
    switching to a type 83 mercury vapor rectifier, it has a constant 15 volt drop, it's almost like having regulated B+, or so I have read. It will definitely kick up my B+ a bit,
    work those KT120's a little harder. Yes, Amadeus, great movie, very well done, leaves an impression for sure.

    audiobill

    Posts : 271
    Join date : 2014-03-13
    Location : Philadelphia

    Re: Wondering about the KT120

    Post by audiobill on Fri Apr 10, 2015 7:40 pm

    Now, David, between flying free for food and throwing M125s out of helicopters, I'm getting concerned!

    dougmon

    Posts : 65
    Join date : 2013-11-04
    Age : 59

    Re: Wondering about the KT120

    Post by dougmon on Fri Apr 10, 2015 7:53 pm

    TMadden wrote:
    dougmon wrote:

    Well, please report on what you think!

    Listening to them now! Watching the movie Prometheus on Blu-Ray, pushing the volume to fairly "intense" levels.  Compared to the EI KT90's, I'm hearing more headroom, less strain at higher volumes (none really), and the higher frequencies are definitely cleaner, more open and detailed.
    Cant comment on the low end, crossover is set at about 130Hz. Very happy! Great tubes for my M65's!

    Now I'm really conflicted! They sound like something I should at least hear.

    Maybe I'll just split the difference (between EL34s and KT88s) and go for some KT77s.

    deepee99

    Posts : 1260
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Wondering about the KT120

    Post by deepee99 on Fri Apr 10, 2015 7:53 pm

    audiobill wrote:Now, David, between flying free for food and throwing M125s out of helicopters, I'm getting concerned!
    So should the people below me.
    Actually, helicopters don't fly. They're just so ugly that the Earth repels them. Being a fixed-wing sort, I avoid them at all costs. I've never actually tossed a KT-120 out of an airplane, but being the usual sort of English major that I am, I did pull the bottle off the top of a KT-88 once. You cannot put it back on and expect the same performance, even with gorilla glue. Sumpin about the vacuum stuff. Jim McShane was kind enough to replace it before he got the cheque. I went into the corner with the dunce cap on.

    audiobill

    Posts : 271
    Join date : 2014-03-13
    Location : Philadelphia

    Re: Wondering about the KT120

    Post by audiobill on Fri Apr 10, 2015 8:00 pm

    I just know you've "evolved" from there!!!

    arledgsc

    Posts : 330
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Wondering about the KT120

    Post by arledgsc on Fri Apr 10, 2015 10:14 pm

    The KT-120s should be on everyone's bucket list in amp that can handle them. Clear, open, and not tizzy on top. Great punchy bass. Last a long time, relatively inexpensive, and my favs in the ST-120 amp.

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: Wondering about the KT120

    Post by MontanaWay on Sat Apr 11, 2015 10:09 am

    arledgsc wrote:The KT-120s should be on everyone's bucket list in amp that can handle them.  Clear, open, and not tizzy on top.  Great punchy bass.  Last a long time, relatively inexpensive, and my favs in the ST-120 amp.  

    cannot agree more!
    I use them in all of my bigger power amps! They sure got those tubes right! cheers

    Maintarget

    Posts : 208
    Join date : 2013-02-10

    Re: Wondering about the KT120

    Post by Maintarget on Sat Apr 11, 2015 2:13 pm

    What arledgsc & MontanaWay said........ Laughing

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Wondering about the KT120

    Post by sKiZo on Sat Apr 11, 2015 7:15 pm

    Thread's a good reminder though. Been meaning to swap the KT120's back into the ST120 here. Been burning in those shiny new TAD KT88STR's. Nice tight sound on those ... be interesting to see how they compare now that I've been away from the big bottles for a while.

    UPDATE: It's the little things. Swapped the KT120's back in and the bias was up around 70 per tube at the same settings where the KT88STR's had been a rock steady 55. Apparently the KT120's are more efficient at idle?

    Also found out they're apparently more sensitive to microphonics. I was getting some of that good old boink ring boink ring thing out of the speakers when tapping the tubes or flipping switches. Swapped out the 12BH7 I had been using for another one, and all is well.

    I'll let em burn for a bit before putting the music to them.

    AND YET ANOTHER UPDATE:

    (bang bang boom boom)

    Courtesy of Beth Hart. Got a tight little bottom she does!



    On the KT120's as well.  ;-}

    Good system test. Nicely engineered and great tunage. The tubes are as tight as I remember them, with solid punch and nice definition. Gutsy bass line with every note distinct without burying the toms. Piano's got some serious depth to it, and the horns are sharp.

    Especially true when pushing the bias to 60 ... that makes these tubes come alive! Not advisable on the smaller amps, but not an issue with the ST120 and monoblocks.

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