New KT150 tubes?


Has anyone any experience with these pretty new tubes. There are already one or 2 amps I know of, that use them. The review of one of these amps in a UK magazine suggested they were a little warmer and more natural sounding than the nearly new KT120's

The article also suggested they were a straight swap for KT120 based amps, with no adjustment necessary. They are more than twice the cost of KT120's, but still not too costly compared with NOS tubes. I know changing from KT88's or 90's to 120's. did require some amp modification. I have an ARC reference 75 and might want to try the new tubes at some point, ARC don't seem to have a customer E-mail service, to ask the question
david12
What if Putin decides to get back at the "West" by cutting off the supply of KT150s? What will audiophiles do then? 8^)
Well Folks, at long last, we may observe at least one product line where ARC is intent upon an implementation of the KT150.

http://www.monoandstereo.com/2014/05/audio-research-galileo-line-new.html

Reference 150 and 250 SE upgrade models perchance?

I think it's lame to design a tube amp that doesn't allow you to easily see the tubes...The Rogers EHF 200 gets my vote for current KT150 design champ.
I agree. Tubes are the ultimate audio eye candy. If sound quality and value is equal between two amps, I'll take the one that shows the glass every time.
I see that Quicksilver is now offering their V4 and Silver 88 monos with the Kt150's. Anyone heard either of these yet? (Added bonus - the tubes are completely exposed, therefore lowering the amp's "lame-osity" quotient, WolfÂ…).
Tubes and VU meters...I put my Squeezebox on the VU setting a lot. It makes digital seem warm and comforting.
If you go to ARC's new web site you will see what looks to be their new amp. It's not out yet however, and the curious thing is...it's using KT-150's. Surprise! They don't tell me anything. Are the KT-150's downward compatible you ask? No answer yet..
The new G series will use KT150 power tube. According to the usual ARC way of doing things, there sure be a way to upgrade existing amps to KT150. Fingers crossed.
Gary (Hifigeek), I caught that pic too. Just a peek though. What's with all the suspense??
Haven't the foggiest idea. They normally don't post pics of products that are not available yet. The G series will be very expensive, that's for sure!
Gary (Hifigeek), does the G series employ some new technology? Or is it some type of super reference amp designed to mate with the Ref 10 and Ref Phono 10??
I just started a new thread where I report on ARC's new G series. I have a URL x-ref to where you can see pics and prices.

It's a new "higher-end" series which is priced higher than the "normal" Reference product equivalent analogues; namely: the Ref 5 SE and Ref 150. There's also an integrated version of the Ref 75. The G series is really gorgeous and uses the new KT-150 power tube.

Looking forward to reading and learning more about the G series.
Here's some pics:

www DOT theaudiobeat.com/highend2014/highend2014_arc.htm

Gary, TAB says the new models "are 'reimagined' versions of current models." Do you know yet if the G series incorporates new or improved technology, other than the KT-150 tubes.

Just speculating of course, but if the G series is essentially repackaged existing products, the use of KT-150 tubes may permit one or both inferences (or surmises) that (1) the existing product line can handle the tubes and (2) that ARC completed "life testing."
I have no idea.. I will have more info after next weekend after the hi-fi show in Newport.
Gary, my non-tech instinct (surmise) is that the KT-150 should be a drop in option for ARC's current Ref series amps (75, 150, 250 and 750). I base this conjecture on the following facts: (1) the KT-150 plate draw is just a few milli-amps more than the KT-120; and (2) the KT-150 plate impedance is very close to the KT-120.

In the former case, I would be surprised to learn that the current Ref amps already beefed up power tranny couldn't handle the slight power draw increase. In the second case, if the KT-120 and 150 tube impedances are in the same neighborhood, I would think that the output tranny should do a good job with impedance matching.

If my recollection of the facts is correct, I am puzzled why the KT-150 isn't a non-brainer tube rolling option. I'll double check the KT-120 and 150 specs and report back if my recollection is faulty.

I wonder if ARC's reluctance to "sprinkle holy water" on the KT-150 has anything to do with the pending 2014 introduction of the new G series gear, which apparently will use the KT-150. Well .... as I have written before, I trust ARC and will not drop in the KT-150s until ARC blesses the new tube. I have too much invested in my gear to impulsively drop a component into my Ref 150 until ARC says its ok.
Gary ... I don't like to guess or talk about stuff above my pay grade. So, I checked the New Sensor web site and copied the following specs:

KT-120

Plate resistance - 3000 ohms
Heater characteristics - 1.70 to 1.95 A
Plate current – 135 to 165 mA
Plate dissipation – 60 watts

KT-150

Plate resistance - 3000 ohms
Heater characteristics - 1.70 to 2.00 A
Plate current – 150 to 180 mA
Plate dissipation – 70 watts

I really don't know if the increase in plate dissipation current or plate current draw is electrically significant. Perhaps you can weigh in. However, to the extent that plate resistance is an important spec, the two tubes share the same stat.

Regards,

BIF
I don't have an answer for you. I will have to differ to ARC and wait, but I am getting impatient. I will ask again next week.
Appreciate feedback from someone who tried them in CJ gear (their techs stay on the official stance, not even supporting the KT120s). I am pretty happy with the KT120 in my LP140m, seeking more depth in imaging and a bit clearer highs.
I was at The Show in Newport Beach this weekend and walked into the Alon Speakers room hosted by their designer Carl Marchisotto. Low and behold he was running a ARC Ref 75 with KT150's in it. He said, and these were his words, the differences between the KT120's and the KT150's "were transformative." No other room at the show including ARC dealers, were running KT150's. I did not ask Carl where he got the KT150's from or if ARC was a co- sponsor of his room. The plot thickens.
No...we need to wait...when 120s were thought to possibly be a threat to mankind itself and reported amp issues relative to higher heater demands were exactly zero...zero...we were cautious and...well...uh...nevermind.
HiFigeek That is very interesting to hear about the ARC Ref 75, running KT150's, you saw at the show. Did Carl say there had to be any modifactions to the Ref 75 to take the new tubes?

I will also hold out for ARCs opinion when endurance testing of the KT150 is over.
Wow! What we need now is a volunator to try KT150 on his ARC amp. Is anyone willing to do that?
I could imagine there are a number of people who are running KT 150's in their REF75 (or other amps) but would not want to volunteer that information in a public forum for fear of voiding their warranty. Knowing that Carl Marchisotti has made the switch and is happy is enough to try it and upscale audio and others sell matched quads of KT150's. The real issue for some may be whether
they are willing to break the principle of their warranty with ARC and use something (even if its safer and better) that is not approved. I myself have cut the tags off my mattress though the warning says I would void my warranty to do so.
Tli...what you suggest requires bravery and utter selflessness well beyond what most would be willing to risk...and a little over 300 bucks.
Let me clarify, Alon in now Nola Speaker. KT-150's are still in life test with over 4,000 hrs on one set of tubes. This is good news. I'm sure they will be a drop in replacement for ARC amps that came from the factory with KT-120's. That being said, I'm still waiting for the ARC engineering dept. blessing. Hopefully it will be soon.
Ariess ... a related issue to the one you just mentioned pertains to resale. My ARC Ref 150 amp is used. I'm not sure how I'd react if I learned that the prior owner used KT-150 tubes if ARC had not blessed their use as of the date I extended an offer. Of course, if ARC sprinkled pixie dust on the KT-150s by the time I was ready to make an offer -- then no harm, no foul.

As an fyi -- ARC recently told me KT-150 life testing continues. Hopefully, I will survive ARC's life testing process. Seems like it will take a life time. :)
Just to be fair, I only recommend and use tubes from ARC. They are 'properly' matched and tested for at least 24 hrs at RATED VOLTAGES prior to being shipped. ARC products are too expensive to play Russian roulette with.
As an fyi -- ARC recently told me KT-150 life testing continues. Hopefully, I will survive ARC's life testing process. Seems like it will take a life time. :)
Bifwynne (System | Reviews | Threads | Answers | This Thread)
Wow, you ask ARC? Didn't know you're a CERTIFIED FREAK-IN AUDIO RESEARCH TECHNICIAN?
The "life testing" of 150s has taken so long that it's starting to freak me out...I can't take it...keeps me up at night...what will ARC say? What if they say NO? Then all my excitement about pickle shaped overpriced retro-tech microphonics resisting room heater dildos will have been for NOTHING. Damn...
Wolf .... I am VERY, VERY upset. Nola Speakers used KT -150 tubes in a Ref 75 .... So far, because KT - 150 life testing is ongoing, Nola may (??) have used the tubes without an ARC pixie dust sprinkle. I may turn this over to ARC for disciplnary follow up -- abuse of equipment. Could result in equipment confiscation. :) LOL

www DOT theaudiobeat.com/newport2014/newport2014_favorites.htm

P.S. -- I wonder if Nola got dispensation.
Last thing I need is somebody coming to my door at 2AM to confiscate my tubes. Or maybe that's the second to last thing...in any case it's a thing.
Wolfy ... you'd be quite fortunate if it was JUST the tubes. Unauthorized tube use could cost you the amp.

Who in their right mind would willfully and knowingly abuse their ARC amp by using tubes that weren't sourced from ARC. Shocking!!!

Sorry if I'm pushing into your personal business, but please confess ... how often do you check the bias of the tubes? Do you religiously set the bias at 65 mV??

Just tryin' to be a friend. :)

P.S. Upscale Audio sells the KT-150 for $92 a pop. :)
The "life testing" of 150s has taken so long that it's starting to freak me out..
Wolf -- Look at the bright side. The longer it takes the life testing the longer tube life it has (Duh). I'd consider it a good thing. But I already have the blessing of Octave for my amp. Another thought - Since they now have a new amp that uses the KT150 they must like them. I'm just waiting for my local tube guy (Jim McShane) to sell them.
Confessions: I don't own an ARC amp, but I approve of them generally, and I'm really in no hurry to try 150s so no amps shall be harmed around here. Also, I check my bias on the factory upgraded (I mention that fact to show I care) Jolida 502p I DO own fairly often for no reason other than I have a meter and enjoy risking knuckle burns. I've noticed the LEDs used for bias setting on this amp are very accurate so really the meter is unnecessary, but I do it anyway...500mv per the manual, and the bias on the 120s stays on track really well, even after over 2 years of abuse. According to the Absolute Sound mag I got yesterday, Jolida just put out a new line of power amps with KT150s called "Luxor", and since Jolida hasn't updated their website since 2004 you have to dig through United Home Audio's site to find anything about them. Somebody get those guys a publicist!
Comment from an ARC REF75 owner residing in Seattle.

"Call ARC. My dealer did, and they told him to tell me to go ahead and put them in my Ref75."
From the same, as yet, unsubstantiated source.

Marc, If not too much of an imposition would you mind inquiring, via your dealer, as to ARC's position with respect to the REF150 please.

"I was told that they recommend them in all kt120 based products. But you can also call arc yourself..."

We are still but Agaricus bisporus to the omnipotent Audio Research Company.
From the same unsubstantiated source.

Marc, If not too much of an imposition would you mind inquiring, via your dealer, as to ARC's position with respect to the REF150 please.

"I was told that they recommend them in all kt120 based products. But you can also call arc yourself..."

We are still but Agaricus bisporus to the omnipotent Audio Research Company.
Tsushima1 .... very interesting bit of news ... but I'm still not dropping those pickles into my amp until ARC says it's ok. Why the wait? Dunno. But until ARC sprinkles pixie dust on the KT-150s ... not in my amp.
Apologies for the double post Folks!

Until such time as ARC issues an official statement, sanctioning the use of KT150's in specific model's, I quite understand your cautiousness in this regard Bifwynne.
However,

When one considers that It would appear ARC have been 'life' testing this valve for over a year now, Albee that in conjunction with the development of a new product line, I find it inconceivable that ARC-R&D have not concluded whether the KT150 is safe to run, or otherwise, In specific models within the current Reference line.

Therefore, why there is still no official directive in this regard from ARC is, at best, a mystery, at worst, close to the choreographed confusion of real farce!
Tsushima1 ... I believe to a near certainty that the KT-150 will do NO harm to my amp. Nevertheless, I will not drop that tube or any other tube type into my amp until and unless ARC formally announces its approval. Period.

I don't know why ARC is taking this long to announce its approval. Maybe "life testing" takes this long. Or, maybe the delay is wrapped up in some way with ARC's pending release of the new G Series. Dunno.

As an aside, I still have about 1000 hours of life on my KT-120s. So, in a way, other than mere curiosity, I'm in no rush. Also, the KT-150s will cost twice as much as the KT-120s. Why the extra cost??? Haven't a clue. Supply and demand??? Dunno.
My 120s refuse to die, and there is no reason 150s should cost much more than 120s, except for greed and market demand, which makes the world go around. That and momentum in space and gravity...or something.
Well folks, further somewhat encouraging news ~

"@bsandovalb, Do you know whether the owner of said Ref150 had sought/obtained official sanction for this, either from ARC Central or an ARC authorised dealer ?"

"Hi, in fact, the owner is the local ARC dealer, he also put kt150 on two ref75 owners.... Both also very happy!"

Only to be countered shortly after by this ~

"I sent aquestion to Audio Researchon using KT150 and this is his response:

One user has filled in a contact request from the website Audio Research
It follows below the summary of the data filled by the user:
Name: FRANCISCO
Surname: CANO SANCHEZ
Message:
Hi. I own AR Ref 110 and AR Ref 150 (Bi Amp, B & W 802D). I wonder if I can use the new Tungsol KT150 in my two amp, and if so, how to adjust the Bias"

"Hello Francisco,

The KT150 has not been approved for use in the Ref 150.

Best Regards,"

Kalvin Dahl
Customer Support Manager
www.audioresearch.com
service@audioresearch.com.

Now, does this mean~

ARC-R&D Has conducted full testing of the KT150 in the Ref150, concluding that the extra draw of eight OPT's left too little of a safety margin with a Single mains transformer?

Or,

Testing of the KT150 within our current Reference Line is still on-going, therefore at this time "The KT150 has not been approved for use in the Ref 150"?

Or,

Just be grateful for this single line of Obfuscation.

Is it really too much to ask for a reasonable disclosure on this matter, set in context?.

We're testing now to be complete, and conclusions have been drawn, again, Is it really too much to expect an official statement to be made, together a list of which models are, or are not, cleared for use with this Fekin Tube!!!

If only Mushrooms had teeth, we could be pulling them out with pliers.
Tsushima1, why get so wound up over a tube change from 120's to 150's? Ive heard the ref150 and it is a stunning amplifier out of the box. There is also some serious time involved in life testing. You see, you cant just test 1 set of tubes in 1 amplifier, you must test a multitude of tubes under various real world conditions, voltage variations and speaker loads. ARC must also see how the tube acts in a given circuit when mis-biased. It would probably surprise you how many people don't bias properly or frequently. If you want to try the kt150's, cowboy up and buy 2 quads and drop them in your amp. If they sound great then you have your answer, if they blow a resistor or two and you have to take your amp in for repair, then you would also have your answer. At the end of the day though, we would all be outraged if ARC said "sure, try them" and they cause a problem. There would be a thread started here on Audiogon slamming ARC for shoddy testing procedures.

In due time, Im 100% positive ARC will green light the 150 for use in their current product line, just be patient.