Certainly in my Ref 75, the 120's and 150's are a straight swap, using the same bias range on the VU meters. No problems with my amp after about 50 hours use.
As for ARC, I suppose you might say, why should they approve the tube swap when they want you to buy their new range. It's still annoying to their loyal customers however. |
The latest data from my uber-scientific research regarding "damage from 120s/150s due to filament draw" says they will not damage a god damned thing. You can read more about this study in my earlier post, and if they damage your ARC it will be the first ever reported incident of this sort of damage and I'll send you a little certificate to commemorate the event. Totally worth the risk...and to update the status of MY new KT150s: They are GREAT sounding tubes. |
Veerapaneni ...my Ref 150 is almost ready for a retube. The KT-120s have almost 2000 hours of use on them.
I am frustrated that ARC will not bless the KT-150 for use in their current Ref series. At this point I have only ONE question: will the KT-150s damage my Ref 150? Period.
I'll take my chances on life testing and sound quality. I just want to know the answer to that simple question. Will I damage my Ref 150
Though a non-techie, the KT-150 additional current draw looks immaterial as compared to the KT-120. The GS-150 and Ref 150 specs look identical. I infer that the GS-150 is a goosed up Ref 150, with just a prettier fascia. It is not even clear to me that the GS-150 has better innards.
Take a look at the ARC web site and check the GS-150 and Ref 150 tech specs ... IDENTICAL in every reported aspect!!!
As many of you who follow my posts know, I am an ARC fan. But I am getting a tad irritated by ARC's refusal to answer my question: will the KT-150 damage my amp???
Bruce |
Ordered KT150s for My Reference 250s Today . |
Smoffat, I replaced my GNS modified Classic 120s driving Verity Parsifal Ovations with an ARC Ref. 150 about 6 months ago. The amp is tubed with KT 120s. I must say that the improvement was remarkable, with tighter bass, a less colored midrange, and more extended highs. I was unsure before making this change if the Ref. 150 would really make all that much difference but it did. In fact, the improvement in my system by replacing the amps was greater than replacing my GNS modified Ref. 1 preamp with a Ref. 3.
Randy |
Smoffatt, the ARC Ref 75, you have to leave the cage off, but I agree it is good to see those tubes. I understand this is NOT true of the 150 and other models, the top can stay on.
When I auditioned the Ref 75 with Wilson Duettes, I compared it with the then new VSi75 integrated and a Ref 110, retubed with KT120's. No competition, the 110 was near the 75, but still a clearly audible difference. An experienced reviewer and owner of many ARC amps, commented that the company periodically puts out a barnstorming power amp in the 50 to 100 watt range, one that people remember for decades. He thought the Ref 75 was one of these. Mine certainly is'nt going anywhere. Besides I am retiring next week, I can't afford constant upgrading. I don't know how to improve on the Ref 75, much south of $30000. |
Hey guys, with your KT150's installed in your REF75 and 150 respectively, was clearance with the cage an issue? Do you have to leave it off. You would not want to "encaged" those beautiful glowing 150's would you??
Me, i have been operating my Classic 120 monos with cage off for years. Not that i have a clearance issue as i use 16 6550 SED Winged C.
I am considering replacing the Classic's with a REF75 or 150. Will likely audition both in my system to see which one can drive my Verity Parsifal Encore most efficiently. My room is fairly large (15.5' x 25' x 7.5'). Would love to audition a REF75 with KT150's but my dealer's demo has the 120's in it. He tells me that the REF75 is sonically superior to the 150 but in my room and with my speakers, the 75 may run out gas at high listening level, hence a 150 being a better fit. Will have to see for myself. He's got 2 used REF150 for sale (customer trade in) that i could get a great price on. |
No, I did'nt know it was on and I don't get to the wicked city very often, it's to expensive and time consuming. Did you go? I wonder if they had ARC's new GS amp series there, not that I would be tempted to buy them, I am very happy with my amp.
I do go to Guilford Audios get togethers just south of Reading , when Trevor puts them on and excellent they are. |
@ David12, I'm curious as to whether you attended the GS series soirée at KJW1 this weekend past? |
Happy to report that the 150s are great...not unlike the 120s initial impression of effortless expansion of the whole frequency spectrum, and it seems the amp is a little louder, although that could be my imagination...little more heat but no biggie, bias is even and holding fine (after initially biasing them to the 500mv amp specs, all of the tubes were up 50mv when I re-set them later, no clue why but at least they were even!). My only criticism is that there's less filament glow like my newly installed "hidden filament" GL 12AX7s...I want more glow damnit, but will learn to live with it somehow...at least my Mullard 12AT7s look alive... |
I've been using tube amps since about 1962 (albeit that was my cousin's white Bandmaster guitar amp), and anytime my Nutz get into a thread, well, it's a good thing...note that with all of those tube guitar amps nobody cared one bit about warm up or bias...we silly kids had no idea what bias was (I assume the repair dudes did). In any case, I've swapped the tubes out of my Jolida plenty and always turn the bias WAY down...after dialing the bias back and sticking new tubes in (and looking out for explosions or large flames) I wait a while and reset it, then check it again hours later...most tubes seem to stay in bias fairly well after the first warmup tweak, but I'm a serial tube finger burning bias freak anyway so I'll be poking it with my meter probes willy nilly. |
Wolf_ whilst In no way insinuating you to be a Numb Nutz....around valve gear, however, i'd be inclined to back the bias right off of the incumbent valves, insert the 150's, then steadily increase bias back to to circuit spec or close to on the conservative side for a while. |
Wow great price Wolf. But sue to write how they sound especially compared to the KT120's. |
I completely forgot how old this thread was, and I just re-read the whole thing (something I never do)...I've been using some Sovtek kt88s and Tung Sol 6550s from my "barely used" tube stash once I sensed recently that the 120s might have been finally losing it...I'd like to publicly thank those tubes for stepping in before they're sadly put back in the drawer. I might make some sort of LED lit display for my collection of spent tubes since I love the way they look. I just stuck some new Gold Lion Premium "matched everything" 12Ax7s in my amp and although they sound amazing (really), they DON'T GLOW worth a damn, a fact thetubestore warned about in their hype...they're worth every penny though. Also, in case anybody is keeping track, the 150s cost $269 a quad including shipping. |
I just ordered a quad of KT150s for my Jolida 502p because I live on the edge...also they hit my magic cheapness number on Ebay, so I guess I live on the edge of cheapness. |
Reading across the forums it would appear increasing numbers of Ref owners are loosing patience with Obfuscation Central and are electing to run with KT150's .......
"I ordered 8 KT150s for my Ref150 from Upscale Audio on Friday - I had them overnighted. Before installing the KT150s I re-biased the original KT120s to the specified 65mVDC. I have a device that plugs in between the power cord and outlet letting you see how much energy you are consuming. It also displays real time wattage and amps. My thinking was to take a reading with KT120s installed and then with the KT150s (set to the same bias) level to see how much additional power the KT150s required. The results are: KT120 (331 watts / 3.04 amps) and KT150 (336 watts / 3.10). The difference does not look significant. I don't know how really meaningful these numbers are and would appreciate anyone's thoughts.
The installation went perfectly - I have had no issues so far. I took temperature readings of the internals and the case with an IR thermometer and did not see notable changes.
I have about 6 hours on the KT150s and I am glad I made the switch. Improved bass, more space around instruments, more meat on vocals and a huge improvement on the sound of guitar strings. I will post additional comments when I have more hours logged. Thanks to all for the great information influencing my switch to the KT150s! " |
Gary (Hifigeek1) ... still no official word from ARC yet about dropping the KT-150s into its "standard" current Ref amps???? Has the new G series gear hit the stores yet???
In a private message from Kal a while back, he mentioned that the GS-150 is the best sounding amp ARC that has made to date. He did not answer my question about how the innards of the GS-150 changed from the Ref-150. On paper, they spec identically. |
David12 and Tsushima ... I took a close look at the specs for the KT-120 and KT-150. Take what I say with a grain of salt because I am not a techie, but the current draw, plate dissipation and impedance specs of the two tube types are very similar. I surmise that any additional power demands that the KT-150 would place on the power transformer and other relevant passives would not be significant.
And I continue to wait.
P.S. to David -- how close was the "slave" tube's bias spec to the "set" tube's 65 mV bias number? I ask because for some reason that I cannot explain, IME, the delta between Upscale sourced KT-120 "set" tubes and "slave" tubes specs can be as much as 5+ to 8 mVs??? Not so with ARC matched tubes. |
Well the KT150's have landed and are in my Reference 75. No sparks, explosions or other calamity, oh and they sound pretty good too. Right off the bat, I would describe a tight deep base and a deeper soundstage as initial, favourable impressions.
As Tsushima1 indicates, this is only feedback for the 75, not the 150 or other ARC amps using more than 4 tubes. I am using the same bias as the KT120's. |
Whilst I, And for the most part, concur, with David and Bif regarding this Conspiracy Of Silence from ARC Central, especially in respect of the models sporting a Single Mains/Quad Output ratio, I am a tad less optimistic for the ratio as sported on the Ref150. Although this ratio may still prove safe and workable, within the performance envelope of the KT150 /REF150, under a marginally altered bias setting for the Master tubes ?!?!? |
I have heard from a number of people using KT150's in their ARC reference 75. The only problem is that the tube is taller, so the top of the amp can not be refitted. This does not apply to the 150 or other amps in the ARC line. I have ordered a quad from Upscale and will report the results, assuming the house does'nt burn down wnen the amp catches fire.
I am with BIF, I am sure ARC's silence is connected to the new amps fitted with KT150's. They want us to go out and buy their new shiny amps. |
Veerapaaneni ... I e mailed ARC about using the KT-150s in the current Ref line and whether the GS-150 (soon to be released) and the Ref 150 have different innards. So far, no answer.
Here's my cynical speculation. I think the GS-150 WILL sound better than the Ref 150 only because it uses the KT-150 tubes. Otherwise, until someone tells me that the GS-150 has different innards than the Ref 150, I think it's just a dressed up Ref 150 with KT-150 tubes.
I hope an ARC dealer or ARC service tech catches this thread and disabuses me of my cynical comments. I WANT to be wrong, so please someone disabuse me. But so far I see no rational reason for ARC continuing to be officially mum about dropping the KT-150s into their current Ref line. In the meantime, I wait.
BIF |
@Tsushima1
yes. That what he told me . He went for training to ARC couple of weeks back, and you have to just swap 120s with 150s. Nothing more to be done. I am going to do that soon , My tubes only have 700 hrs and thinking twice to waste them :) |
Does anyone know if you can put the 150's in AR REF 210 monos. |
Veerapaneni, has your (ARC?) dealer been given *Official* sanction from ARC Central for the utilisation of KT150's ? |
I have Ref 250 and my dealer told me I can just swap KT120s with KT150s without any modification . I am going to do this pretty soon. |
David, mere speculation, however I suspect that the ratio of output tubes to mains Transformer(s) might be the issue, rather than power output per se. |
I had an E-mail from someone who went to RMAF and noted an ARC ref 75, tubed with KT150's. I contacted the manufacturer, whom I won't name, but is a well respected US company. He kindly replied saying the KT150's are a straight swap with the same bias setting and no modification required. He also said he thought the sound was a real upgrade. I had already been told by a retailer for ARC, he thought this would be the case, but may not apply to larger amps using more tubes, such as the Reference 150.
When I have some time, I am going to be brave and find some KT150's and give it a go. |
Sent another message to Kal. Waiting for a response. I asked him how the GS 150 differs from the Ref 150. The specs are identical, except the GS 150 uses KT150 tubes. I think there's a marketing wrinkle here. |
It's been a while - any updates on arc kt150 acceptance and release dates of G series? |
Another titbit from elsewhere.
" My dealer has checked with Audio Research and apparently I would be able to put the KT150 in my 750s tube amp without any modification to the units. The only reason I cant do that now is because they claim they dont have enought KT150s on hand to properly match the quantity I need for the 750s. I guess this means they might adjust the bias of the KT150 in such a way that it works with my units. I have no ETA from them since they claim being very busy with the G series at the moment.
I am tempted to try sourcing the KT150s myself but given I am not them impact of the bias current have and the matching issues as well if I was to get them from the web, I guess I will be patient. I only have 700 hours on my 750s anyway so I can live with the set of KT120s I have for now! " |
David256, ARC has unofficially said that their tested and calibrated KT-150s will sell for almost $200 per tube. By contrast, ARC sells KT-120s for about $100 a tube. Way over my what I will spend for a tube. By contrast, Upscale Audio is charging about half those amounts.
When ARC blesses the KT-150, I'll probably go to Upscale. No f***ing way I'll spring for $200 a tube from ARC. My current set of KT-120s is getting long in the tooth. I might spring for the KT-150s with or without ARCs blessing ... maybe
Btw, I read somewhere that the KT-150 has a life span of 4000 hours, which is twice the suggested limit for KT-120s. Let's see what is officially reported, all of which I suspect will be shortly after the ARC G Series is released.
BIF |
hmm, anyone know what the life expectancy of the KT-120's are? I should have about 3000 hours of actual play( more if you include standby) on mine after 2 years of use in January. A quad of the KT-150's is running anywhere from $329~$400, so they are not pricey and could use any incremental power improvement I can get with the Prima Luna Premium integrated amp and Maggies. |
Wolf, .... Undertow makes an interesting point, but ... the KT-150 will list for twice the price of the KT-120. I am dubious that ARC will get stuck with thousands of KT-120 tubes even if the KT-150s are approved for use in the current product offerings.
I've used approximately 75% of the tube life of my KT-120s. I may spring for 2 quads of KT-150s, but not from ARC. Too damn expensive. The good news is I understand that the KT-150s have a life span of 4000 hours. |
I realize you meant AR is one of the biggest tube "users" in the world, but I'd be willing to bet Fender makes their tube inventory look minuscule. Guitar amp companies don't seem to use large tubes like 120s and 150s much if at all (bass amps, with a few exceptions like the mighty Ampeg SVT, are mostly SS) beyond EL34s, EL84s, 6L6s and 6V6s...those are the power tubes of choice generally, and they use a LOT of 'em. I would buy another set of 120s in a heartbeat and likely should since mine are getting a little worn and 150s cost about twice as much...although I did see a quad for under 300 clams recently...hmm.... |
Frustrating is right.
I will start with I have not heard KT150's yet, and don't own an Audio Research amp...
I do have an amp that will work with them however.
But I will say this thread with Audio Research probably went way over the top with ARC owners being way too concerned, and way less about the KT-150.
I believe Audio Research is probably the biggest Tube manufacturer still in the united states, maybe the world.
My answer to why Audio Research has not "Approved" this tube is by far simpler than what is being talked about here...
They are afraid far less about the KT150 killing YOUR amp than they are about it Killing their Current inventory when nobody wants to buy the 10,000 or who knows how many KT-120 matched tubes they already have in inventory ready to go!
As soon as they say 'GO' on the KT-150 officially on the website or wherever who is going to buy all those already KT-120 AR certified sets sitting on the shelf?
Just something to think about. |
@Andrewrona, I was conveying the information from the position of a somewhat frustrated ARC owner, A form of self flagellation if you will! |
Tsushima 1 is your T2000 a mk1 version . |
I was going to get a set of 150s, but now the fun has been ruined by all this yammering... |
Merely wondering whether anyone has news of any recent development on this?
Perhaps slightly tangential yet of interest. It would appear that Allnic Audio are now shipping their KT120 amplifiers, T2000 integrated, A2000 stereo power amp and M3000 monos, sporting KT150's.
" "After listening late into the evening I can say that installing the KT150 valves into the T2000 yesterday has transformed the sound to an extent I would not have thought possible.
It has dramatically improved in all respects. Everything is much more clearly defined, better articulated and more accurately represented.
The first most notable aspect is how much more quiet the background now is.An 'electronic' background has been replaced by the real ambience of the concert hall.
When listening to a favourite 1984 LP recording of Mahler's 4th and with eyes closed there was no hint of there being speakers in the room at all. What was there was a vividly clear sonic picture of the orchestra in the concert hall and I was sitting midway back in the stalls.The physical space was practically visible.
Each instrument was more accurately represented in terms of its characteristic tone, colour and dynamic range and also where it was in the three dimensional space of the concert hall. It was both proportional and in perspective.
The other improvement was in timing and flow. The music flowed more naturally, with more energy and life making the listening pleasure more intense. The KT 150s have made a significant improvement, which for a couple of hundred pounds
is remarkable."
Way to Go AR Central( Where is that I'm with stupid emoticon when you need it) |
I doubt very much whether we will hear of any 'Official' sanction, If at all, in respect to the utilization of KT150's within the current Reference range (in particular to the 75W and 150W models) for quite some time until after the initial retail launch of the Galileo series.
When one considers that their implementation of the KT150 is a notable component element, not merely audibly, but also in the marketing of the New product range (perhaps even more so) then ARC are unlikely to shoot themselves in the pocket on this one. |
Thanks for the update. I think the evidence now is significant enough to call the verdict. I shall upgrade my Ref 250 to KT 150 when the current KT 120 is up for replacement. There should be good improvement in the performance. |
A very recent comment posted on another forum, Dealer/User location as yet unknown.
"My dealer got confirmation i can use the kt150 in my ref750s. They also suggested i wait a bit because they mention with the amount of tube in the 750s, ARC find it difficult apparently to match a large number of kt150 so far. This would not be an issue with smaller amplifier using less tubes. Not sure what to make of it but i will likely upgrade to the kt150 in the near future anyway..."
__________________ |
And from another Costa Rican based corespondent, seeking advise, in respect of an amplifier to drive his Martin Logan CLX speaker,
"Problem solved.
You are absolutely right, following those who recommended to test the amp at home, I did just that and I found the ARC 150 to be just right in the sense that it gives me the full bodied presence I wanted, plus the prerequisite of better imaging and full range of frequencies. Like I said, I tested it and it's staying here. One more additional reason is the dealer brought it with the KT150 tubes already installed, so it made a huge difference. Thank you all for helping solve this little riddle and let me say I am happy. It worked great." |
At this point I do not recommend using the SED6550 (winged C).
Before production stopped, (the factory burned down supposedly), these tubes became very problematic. I only use the 6550we at this point. |
As an ageing cynic, really ARC have no interest in showing the 150's will work in the current Reference power amps. They have the reputation of bringing out new models faster than a Milan fashion house. I would put money on them having a range of Reference power products, using the 150's, within a year or so.
" Step this way Sir for the new super reference Power amp, the 120's are so last year" Anything is possible. New SE model, KT120 inventory too high, haven't decided if new resistors are needed ... I have a friend interested in ARC Ref250. The only reason hasn't pulled trigger is uncertainty of KT150. He spoke to a big ARC dealer past Mon and dealer said ARC is very happy with sound of KT150 in Ref amps and should work fine without problems. But since ARC hasn't officially endorse using them, he can't officially endorse them either. Friend is exploring other options so I think the uncertainty has some negative effects on sales. |
Cmalak -- I haven't tried the KT150 in my Octave V110 but I have tried the SED 6550 and the KT120. Both have very similar sonic signatures. When I was looking for SED EL34's a few years ago (had the Octave V70se then)I met with Jim McShane and he told me about the quality of SED tube taking a nose dive. He said that Arc was the largest customer for SED tubes. In fact when I got my V70 the SED 6550 was the stock tube with the SED KT88 as an option. The KT88 is a much warmer sounding tube. |
As an ageing cynic, really ARC have no interest in showing the 150's will work in the current Reference power amps. They have the reputation of bringing out new models faster than a Milan fashion house. I would put money on them having a range of Reference power products, using the 150's, within a year or so.
" Step this way Sir for the new super reference Power amp, the 120's are so last year"
An unworthy thought I know. |
I am going to call Kalvin at ARC and ask him about the use of the KT150 in my Ref 110. I suspect that they haven't nor will they test it in the older generation Ref amps (unless there is sufficient demand/enquiry on the part of owners to do so)but will push them to see if I can get a definitive answer. I will also ask about current Ref amps and if I get an answer will report back.
Separately, if the answer definitively comes back as no for my specific question of dropping the KT150 into my Ref 110, does anyone here have a view as to whether the Winged 6550C SED tube is preferable to the KT120 tubes in the Ref 110? It seems like of all the 6550 variants, the Winged SED version is the top dog and often goes for big bucks but wasn't sure if anyone here has compared it, either to ARC standard issue 6550s or to the KT120?
Would appreciate any input on this front. Thanks. |
I sure as sh*t, I am not dropping those pups into my Ref 150 until ARC gives the green light. So, I'm taking my own advice. It's your amp and you can do whatever you want. There are players and spectators ... what makes the world turn. |
