Questions on KT150 tubes

Does anybody here have experience using that tube? Can you tell me how it sounds? I have a Primaluna DiaLogue Premium HP and it can use them but they aren't cheap. I'm running the stock EL34s and LOVE it but seems like this tube is all the rage. The Primaluna is unbelievable for its tube magic as-is. Also I wonder if the KT150 would last.

Also the best places to buy them. Not the cheapest. The best quality.
Congrats on the Primaluna as I'm hearing more and more great things about them. So much so in fact that a newbie friend of mine about to take the audiophile plunge has requested my help in putting together his first system and I'm probably going to get him going that direction. As for the KT 150's they are a phenomenal tube and generally I am highly recommending them, especially if you are using any other KT series such as 88's/6550's or even the 120's. Your case is a little different though as you are loving the EL 34's ( as I also do) and I can tell you right now the 150's are pretty much nothing like the 34's. IMHO you simply won't find the 34 mids in any push pull tube design I know of. It's not out there. Some say a KT 66 or evena 90 may have some similar mids but I haven't personally ventured that way to know. I can tell you the 150 is a better overall tube than the 34 when you consider the entire presentation: even balance, grain free, remarkable extension both top and bottom as well as ruthless, effortless power.. Just to name a few. But, as nice as the mids beautifully blend and sound fine they do not do the 34 thing..... If I were you I might try a set of EH KT88's first and you'll get a very good feel of the KT family sans the omnipotent power of the much pricier 150's... Then live with them awhile and think about the 150's down the line.
Thanks. I have heard that the KT150 has a gentle midrange. From my research I won't go from an EL34 to a KT88 or KT120. They sound more technical is the word I get.

I'm so glad I got the PrimaLuna. As time goes on I'm more and more enamored. FYI most of the PrimaLuna owner's I interfaced with here and on other forums were not newbies. Almost all of the ones I spoke to directly had owned a lot of tube gear and finally found something satisfying and not difficult to live with.

So I might drop some coin on KT150's. My understanding is that in a PrimaLuna they might go 10 years because they are run so easy. We'll see. I like what I have now.

I appreciate your note!
Any followup on the KT 150s? I also have a Primaluna HP Integrated and am curious about this tube. I have the stock EL34s which are nice, but am thinking of venturing into a more powerful tube. I don't want to get too clean and want some body to the sound. Any first hand experience or tube comparisons?
KT150s are amazing sounding tubes, and after replacing my nearly 3 year old KT120s (they served with distinction as I work 'em fairly hard) about 12 months ago I have to say they don't make me want to ever use anything else in this amp (I have KT88s and 6550s that patiently stand by and also sound fine, but the 150s just work))…big sound, more effortless power (seemingly)…I bias at the amp's recommended 500mv point and they just stay there…large glass power pickles.
Ditto with what the "Wolfman" says. I have KT-150s in my ARC Ref 150 SE. When listening to music selections that I hadn't heard in a while (pre-KT-150), I am amazed by the difference.

Yes ... they are expensive, but ARC tells me that the KT-150s should last 50% longer than the KT-120s (3000+ hours as compared to 2000 hours).
What sonic differences do you hear in the KT-150s compared to the KT-120s? I have been running KT-120s in my Emotive Audio amps for a couple years but no tubes last for ever. When replacement time rolls around, I am wondering what to expect if I get 150s instead.
I have the same Jolida amp as the Wolf_Garcia. I had the Tung Sol KT-120s and later got to KT-150s. To me with the Tung Sol KT-150s in place I've got the big and sweet midrange/highs of an EL34 tube with so much for oomph bass wise. The bass wasn't boomy either like when I had JJ-KT88s in my amp. To me when I had the Tung Sol KT-120 in my Jolida I found the music to be ok sounding not a good experience like the Wolfman had. I ended up getting NOS GE 6550 tubes in the Jolida and liking that sound. When one of those tubes blew up on me I then went for the KT-150s after having long talks with Jolida techs to ensure the amp would survive.
My KT150s have been in my amp long enough to erase the  memory of the tubes preceding them.
2000 hours on 120s seems to be about half or less than I got on mine and I had my ear on them looking for any sign of age near their end, and removed them as soon as I detected any tonal weakness (which was minimal but it seemed clear they had done their job)…I bet they had 5000 to 6000 hours on them, and I expect the 150s to last at least as long so we'll see.
I also own a Primaluna Dialogue Premium HP integrated amp.  I play vinyl on my Pro-ject Extension 10 and listen through the Volent VL-2 monitors.  I bought the Primaluna with the stock EL-34 knowing that I would swap all the tubes out upon set up.  I did.  I replaced all stock Primaluna 12AU7 tubes with NOS Telefunken.  Now I have a HUGE soundstage, incredible detail, and 3D imaging.  I replaced the primaluna stock EL34 tubes with Shuguang Treasure KT88-Z tubes.  Wow!  Talk about real bass slam!  These KT88s also offer very extended highs and a natural mid (female voice).  Several LAOCAS friends have come over to the house and have thrown everything they had at the system to find fault with it but to no avail.  Very happy with this tube set up.  I did run the EL34 tubes to compare with the KT88.  While the mids in the EL34 tubes were very lush there was a distinct lacking of real bass snap.  So, I am still searching for the Holy Grail of sound -- like we all are.  I spoke with Kevin Deal at Upscale Audio (Primaluna importer) and he said that he is running the KT150 tube in his Primaluna Dialogue Premium HP integrated.  Kevin affirmed this thread -- that the KT150 has incredible bass slam, very well extended highs, and well tempered, natural (not sweet) mids.  Because the Primaluna runs the power (output) tubes so easy (8 tubes for 78 WPC vs. the 4 tubes in the Ayon Spirit III) he says that they may last 10,000 hours.  So, for the money the KT150 seems the tube of choice.  Just hoping that Santa reads this post!
Lots of amps with 8 power tubes seem like nice things, and I've lusted for that Cary 120 amp for years (I guess after a Cordesman review), but doubling my power tube cost and amp heat output (I think even if tubes are driven less hard they're still little space heaters…unavoidable) is somewhat off-putting, although if a really great deal on a 120 came along…hmm...Besides, my "el cheapo" (seriously) Jolida sounds so good (dynamic snappy tube power, inaudible noise floor, accurate tone) I don't mind keeping the damn thing for a long time, thus freeing up cash for the "next great power tube" outbreak. 
I have a PrimaLuna Dialogue Premium (non HP) running all stock tubes. When I bought the amp I had Kevin send some TS KT-120's. After running the EL34s for awhile breaking in the amp and tubes I switched to the 120's (burned in by Kevin).  Definitely a difference but once I got a feel for the 120's, not sure if I am liking the overall sound. The 120's have a midrange glare or upper energy I am not finding pleasing so instead of buying input tubes to offset the midrange energy, I put the EL34 back in and the midrange is very very pleasing.  So I am not sure if the KT150 midrange is a lot better than KT120?  If not, proceed with caution. Also Kevin told me that the 120's over the EL34 you will gain 1db so if your looking for power he basically said its not worth it. I guess what I'm saying if you like the sound with the EL34 then you may want to think long and hard about the 150's. This is of course if the 150 midrange isn't leaps and bounds above the 120.
Are you saying personal preference plays a part in tube selection? THAT'S INSANE…If 16 people say 150s are what you should like, you should simply put them in and suck it up…even if in your rig they sound like an utter cacophony of screeching dog bleat, there is little room in high end for naysayers.
I assume you are answering my post Wolf? If so, all I'm saying and another poster here has the same opinion (doesn't mean its always right) before dropping $400 I would proceed with caution unless you KNOW the 150 is a much better tube. Also there are lots of naysayers everywhere so take it with a grain of salt. However, mileage varies right? 
I have a pair of Quicksilver Silver 88s using the Kt-150. I bought a quad of Genelex Kt-88s for use in a pair of McIntosh MC60 amps I also have on hand. My thinking after having the Kt88s was "why not try in the Silver 88s to compare with the Kt150s?"  Look, Mike Sanders, designer of the QS hands down prefers the Kt150 over ALL outputs that can be used in his amps. I say the KT150 is HANDS DOWN a much better tube in all respect to the Genelex in direct comparisons in the QS amps. I can't speak for Primaluma but expect the results would be similar, it's a better tube more plate current, more power more EVERYTHING.

Realist all I can say is break down and purchase. I find it extremely unlikely that you will not be satisfied. You want BODY, they'll definitely give you that and a lot more.
My last post was complete nonsense and I stand by it 100%.

I absolutely love your posts, way too funny.
Wolf me too lol. :)  Happy Holidays.
I have a Jolida Fusion 3502 with KT-150's. I think the same model that Wolf and a few others here have. I have to say for under $2K retail this integrated amp sound amazing. I am using a preamp with it and using just the amp part but holy cow! Superb late night listening, big, wide and 3D sound stage. It has clarity, a touch of sweetness and detail. I smile every time I listen. I started with the EL-34 in it and still love them, but the KT-150 are stunning.
Could any of you KT150 aficionados comment on the break in period for these tubes?  I bought a quad to replace the KT88's (Gold Lion reissues) in my DeHavilland 50A mono blocks (after the OK from Kara Chafee) and have maybe 60 hours on them.  They sound tonally more bleached out and not any more dynamic than the KT88s.  Have I not given them adequate break in time, or does this particular amp possibly just perform better with the KT88s, with which it was voiced??
If you are not crazy about what you are hearing after 100 hours, maybe they are not for you.

Is the bias adjustable? Can you lower it or raise it a little to change what you hear? Lower bias will warm up or sweeten the sound, to a certain point.
what is/are the price(s) on the KT 150 ?
$95-105 each depending on matching and quantity.

Agree with Joe.  But double that if you buy from ARC. 

It has been my experience that when I buy power tubes from a respected tube vendor I usually use, he can't get the matched power tubes to bias closely in my ARC Ref 150.  I've tried KT-120s and KT-150s.  Same story. 

At least with respect to my ARC amp, it seems as though ARC matches power tubes by focusing on using different variables.  Regardless of what ARC does, power tubes sourced from ARC bias within a few mVs of each other.  No so from the respected vendor.



Much Thanks! BIF & Joe.
keep me posted & happy listening!
I may try them in my CJ LP140m so feel free to PM me if you don't like your quads.

Also, anyone tried the cryo'd version ? 
This is what to expect to hear in an EL34, KT88, KT120, KT150 tube:  EL34 -- warm lush sweet mids.  Nice bass and highs but without the bass slam OR impact that may be desirable for rock and classical music or even a nice jazz drum solo.  Minimal, but reasonable bass and high extension.  Fine imaging but not jaw-dropping.  KT88 -- much more bass slam and bass extension.  This also holds true for the highs.  Greater sparkle than the EL34.  Mids are dryer than the EL34 (sweet, like candy) but female vocals are very natural and in-your-room present.  Imaging is more precise and detailed than the EL34.  The KT88 offers a bit more power, too.  KT120 -- a somewhat digital sound.  When this tube was first introduced many tubies scooped it up for the increased power.  Fine.  But this digital texture pushed many tube rollers back to the EL34 (much more musical, warm, lush mids,etc.) or even back to the KT88 depending on bass impact preference.  But now that the KT150 has appeared.  The KT150 offers more power and a longer life than any of the above mentioned tubes (about 10,000 hours in a cool running Primaluna amp).  The KT 150 has killer bass slam and extension.  The highs have a clear and very present sparkle (love the clocks in DSOTM).  Imaging and sound stage are alive, full, detailed, and 3D.  Jazz, classical, and rock listeners will really love this tube.  Mids do not have the syrup that the EL34 has (a deal breaker for some listeners) but IMO they are natural, forward, and glorious.  Truly, the KT150 is the tube of choice for those who want excellent bass power and extension, crisp highs, detailed mids (not sweet), excellent imaging, and long tube life.
Excellent post and very informative.  I totally agree with your assessment on the KT 120.  I find them too digital sounding also.  

Dramapsycho posted:

But now that the KT150 has appeared. The KT150 offers more power and a longer life than any of the above mentioned tubes (about 10,000 hours in a cool running Primaluna amp). The KT 150 has killer bass slam and extension. The highs have a clear and very present sparkle (love the clocks in DSOTM). Imaging and sound stage are alive, full, detailed, and 3D. Jazz, classical, and rock listeners will really love this tube. Mids do not have the syrup that the EL34 has (a deal breaker for some listeners) but IMO they are natural, forward, and glorious. Truly, the KT150 is the tube of choice for those who want excellent bass power and extension, crisp highs, detailed mids (not sweet), excellent imaging, and long tube life."

Couldn't have said it better!!

If anyone is interested I may sell my matched quad of 120's from Kevin Deal. At the most they probably have no more than 40-50 hrs. 
I don't recall breaking in the 150s for any particular time period since I replaced a set of 120s that were on their last legs…thus an instant improvement. Also, I can only assume that since all amp designs are somewhat different, so are the way they utilize the tone potential of various tube types…I bought my 150s for under 300 bucks a set (matched, dusted off, weighed, counseled, told to not be afraid of crazy Americans, allowed to say goodbye to tubes who were still in that lonely Russian factory) and if ARC supplies some brand specific mojo I'm not surprised they'd charge you more for these things…another reason to buy a Jolida!
Not just ARC Wolf, all manufacturers' charge more for tubes. Sure don't know why this is so other than their parameters may be tighter and more rejects? In any case the difference between 100.00 a tube and say 150.00 from the manufacturer sure doesn't seem to warrant paying the difference as long as they are close. Is 300.00 a set for a quad, 2 per channel? I typically see for about 100.00 each from tube vendors.
From what I understand, ARC and Conrad Johnson charge more for their tubes because they test them more thoroughly. I also heard that they, especially for CJ, test in the actual amps that these tubes will be installed.

I believe they go through more trouble to weed out tubes that would normally die an early death.

Also, I believe ARC in particular, tests for parameters that keeps the tolerance tighter for their circuits because of the Primary and slave bias aspects of their circuits which require matched pairs.

In my CJ gear, tubes are individually biased, which can help alleviate some of the stricter matching required by ARC.
$269 a year ago for a "matched" (at the factory? A tube dating site?) quad of 150s from a very highly rated Ebay seller. Long live the hot pickle!…just crazy good sounding tubes. 


Before doing the SE upgrade to my Ref 150, I bought 2 matched quads of KT-150s from a respected tube vendor. 

Some pairs biased pretty closely; others were off by as much 6 or 7 mVs, which as I mentioned somewhere, is pretty close to the boundary of ARC's recommended range (between 57 to 73 mVs). 

IOW, if a set tube is biased at 65 mVs, the slave measured at 71 or 72 mVs. The max spec is 73 mVs.

Anyway, I only put about 200 hours on the KT-150s.  Am I offering them for sale?  Not sure.  ARC charges $200 per KT-150.   

I guess I'm lucky…no, wait…I know I'm lucky.
I too have the Jolida Fusion 3502  
Bass on el 34 is tight and punchy,image depth and natural rich midrange without 
Question best with el 34  tube very important for top shelf input tubes
I use 50s black plate Raytheon 12ax7,and GE 5star phase splitter 12ax7 50s tubes
Much better then current made crap. Also Cryo ed tubes EL34 from tube man 

Same Chinelse company that make black treasures which are even better with exceptional Bass. I like a tube that does everything well including natural tone 
And image density the kt 150 can never Big thing to remember Your Loudspeakers and ease of signal I have 94 dB Spatial audio  Hologram-3 
Using top Mundorf caps, reference compression driver with dual 15 inch drivers
Very Easystem load .lowest Xover800hz seamless. That is the key 
And EL34 bandwidth to 28hz with this speaker a exceptional match.
Your speakers efficiency ,and Xovers efficiency will dictate this.