Any thoughts if this will get me into trouble (KT-150 related)?

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joeinid
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Any thoughts if this will get me into trouble (KT-150 related)?

Post by joeinid »

So here I am thinking and trying to sell an ARTsa stereo amp. I absolutely love the CJ sound, but paid more for the amp than the sale price.

I do love KT-150 tubes in my little Jolida Fusion 3502 amp. Granted it's not a CJ amp but it does alright.

I know from friends and others that Audio Research finally "authorized" KT-150's for their KT-120 based amps. Eventually they offered an "SE" upgrade that changed the tubes and made available some circuit changes (supposedly) to take better advantage of the KT-150's. There is still some speculation on any transformer updates with no concrete answers.

Soooooooo, my thinking tells me that our CJ amps (especially the ART series) are capable of drop in replacement with KT-150's from the KT-120's. Of course they are not "optimized" for the tube, but I suspect there will be better performance and since the KT-150's are not run as hard (bias being the same as the KT-120), with longer tube life just like in the ARC amps.

I am SERIOUSLY considering ordering 8 (maybe 10 so I have 2 spares) matched KT-150's from a reputable dealer, drop them in my ARTsa, bias as usual and enjoy it/them until either the tubes need to be replaced or the amp need fixing.

What are your thoughts?

CJ refuses to discuss anything KT-150 related and sadly not much of anything seems to be coming from them these days and I have been a fan since I can remember.

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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by admin »

Sounds like a great experiment. How much do you think ten KT-150's would set you back?
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by joeinid »

Probably $950-1000. I could always just get 8 and pull 1 or 2 from the Jolida if necessary :D

As an example:

http://www.upscaleaudio.com/tung-sol-kt-150/
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by Big Dog RJ »

G'day Joe! and all the very best for 2016. Cheers to good health and good music.

I did get the chance to audition the KT150 in the new ARC gear, and didn't get too excited. After returning home to my humble Classic60SE with KT120's as the original design layout, it put a smile on my face with a better confidence of knowing that c-j really put in some hard hours of research to claim the KT120 as being a better option. Not that the 6550c is no good, just a different flavor. I have not yet audition a c-j amp with KT150's, at one point I was itching to try it on the classic 60SE but this would render useless since it is not designed for a KT150 topology.

Having that in mind, a long lost mate of mine in the UK has actually tried it, and he confidently claims that the so called "improvement" in sound is very subtle throughout mids to highs but the bass is pretty good. Better defined, more weight and more authority, closer to a solid state bass with that extra slam. He goes onto claim that the KT150 tube when properly installed in an amplifier capable of delivering that type if circuit, gives you the best of both worlds- lush midrange, smooth relaxing highs and solid gutty bass with a solid state thump. However, then he claims when listening to the KT120's on a different set of speakers, he gets an equal level of performance, and having the newer KT150 may seem more of a "psychological" aspect rather than an actual sonic difference to experience.

I strongly feel that I need to listen to a properly designed c-j amp having the KT150's used to its advantage because those expensive new Audio research power amps didn't justify the price tag- regardless whether they had KT120's or KT150's. The REF75 on the other hand with KT120's is actually pretty impressive, and I liked it when it was driving the big SF Strads. I think ARC is headed in the wrong direction here, offering customers so called sonic upgrades with KT150's as replacements and charging the customer quite a high labor charge. Whereas c-j doing the series 2 upgrade thing for their ART, ACT2 and GAT preamps and other series in power amps makes far more sense with capacitor upgrades and resistors, plus internal wiring. c-j always seems to know what is best and how to stick to their motto- after all "it just sounds right."

If I were you, I'd wait for c-j to put out a newer model having incorporating the KT150's as an original design. I also think it would be a very close call between a KT120, and all this excitement is actually hype...

Have you heard of any other brands using the KT150's to the fullest in their newer designs? If so let me know and I'll try to audition something here and report back. Every time I audition a so called new model of some well known brand, it's usually the KT88 or EL34! Not even the KT90, which I used to have in my Manley 350 Reference Series monoblocks back in 1998-2004. The EL34 and KT88 have been around for nearly a century, and they still produce some dam fine music. The old classic McIntosh and Quad amps come to mind, very musical I must say and totally enjoyable. Partner these classics with a PV12 or a vintage ART pre and you're in heaven!

Cheers Joe and let us know your quest for perfecting the KT150 tube.
RJ
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by joeinid »

Hi RJ,

Thank you so much for your thoughts and insightful post. I know what you are saying and agree. I did get to hear an ARC GSPre with the GS150 on Wilson Sasha 2 speakers. I will confess to not being much of a Wilson fan but I actually loved the Sasha 2 and the newer Wilsons with the soft dome tweeters. That combination I heard was outstanding but I don't know how listening longer term would pan out. ARC and Wilson are, to my ear, more lit up, more open and neutral. Tone and density doesn't seem as full but could be great in its own way. I'd have to live with it to understand what I'm hearing.

I just received an ARC Reference 6 preamp and it's pretty special. Break in is somewhere between 300 to 600 hours so I have a very long way to go. I honestly believe the Ref 6 and GS 150 combination on my Strads will be outstanding. But again, I'd need to live with it to understand the long term satisfaction of that combination.

Let me know if you hear anything regarding the KT150 in either the current amps or new designs.

One benefit I can see right away is that the KT150's would be biased as KT120's in the current amps. This will definitely afford longer tube life as there's less stress on the tube and, I think, a lower bias may result in a slightly sweeter sound. Just my 2 cents. Our amps should be able to handle the KT150 without any trouble, in my opinion.
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

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Yes Jo! The ARC Ref6 and GS150 are quite impressive with SF Strads- I heard the system myself.
Exactly what the dealer has here in Melbourne. Now this is the actual ARC/SF dealer that has been around for decades, same chappy I purchased my Rega TT from. My my other dealer buddy who is the distributor for cj/Quad, doesn't see eye to eye...

Therefore, I'm actually waiting for c-j to put out a new amp with KT150's. They took so long to finally decide on KT120's that now they are offered as options between 6550's as well, for those who still prefer their 6550's and why not. I sincerely don't think c-j is going to bring out anything with KT150's for this year. They would rather try to focus on these "series-2 upgrades" that they're offering. I feel somewhere around late 2016/early 2017 we may begin to see something with KT150's if at all...

So it's very interesting whenever I am called in for an audition, it's like watching a live bout between Tyson vs. Holyfield. Now it's like watching MMA vs. UFC, too many blows to the head and in all directions because the systems price tags keep going up, and then when I get home I actually remember what it's all about- the music!

So now, I've focused my spend on source material, most of my money these days goes into finding rare LP's and Sort Kones. Just the other weekend, I picked up a Roberta Flack LP- outstanding stuff and highly musical even though a bit of surface noise, who cares. Now, this is when you're really enjoying your music. I have another very rare LP by Charlie Hayden and Kenny Burrell, plenty of surface noise and gets picked up big time by the Quads. However, since just recently one of my Quads needs a fix up, I've been using a pair of monitors from Jas Audio (Orsa's) that has twin-ribbon tweeters and Moral drivers from Israel, bloody great sound! Kick ass dynamics, very fast transients, smooth highs and expansive midrange. Bass is alright, goes down to about 40Hz but can't do the lower registers like big stats, which go down to 28Hz. On these monitors, the extra surface noise is not a major issue and is therefore listenable. Charlie Hayden plays some serious bass notes and when Kenny Burrell kicks in with this awesome strings, it is just divine, some superb musical synergy going on with this group. Wish I could see these guys play live one day, I'd probably have a heart attack!

So, lets see what c-j has to offer in the near future, I won't be surprised if the whole KT150 project is put on hold for a while.
Cheers, RJ
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by joeinid »

Hi RJ,

A friend was talking to Bill and Lew at CES in Vegas. It doesn't look like any KT-150 based amps are ever going to see the light of day.
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by Joe Appierto »

Drs. Conrad and Johnson are undeniably purveyors of top tier audio equipment. They are also both economists and as such are highly pragmatic. When the production of GE 6550A output and small signal tubes ceased c. 1985 they knew that their customers could continue to rely on the existing reserve stocks of c-j. But they also knew that alternatives supplies would be needed for future products. In 2003, they introduced the Premier 140 which was their first power amp designed entirely around Russian tubes: a 6922EH input tube, Sovtek 6H30 phase splitters and SED 6550C output tubes.

The supply of 6550C tubes then became problematic both in terms of quality and availability. Although Kevin Deal at Upscale still appears to have a good supply of them, c-j may have felt it was still an iffy situation and c-j switched to the New Sensor KT120.

I'm not sure what would be their motivation to switch to the twice as expensive KT150.
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by Big Dog RJ »

Yes, spot on Joe! At the end of the day, they are economists and number crunchers, they know how it works and how to sustain a business. Perhaps that's why production hasn't moved to China yet...

Another good example, Eve Anna Manley, when she took over Manley Labs, after the split from VTL, she already had a pretty good professional market going on, hence nearly every professional studio I have walked into, has some Manley gear in it, and they do this professional gear extremely well. The standards are top-notch, and she wouldn't hear of shifting production overseas just to keep costs low. That is why their Hi-Fi division is just a bonus for them, and they're doing pretty well in this department too. Sustainability is the key here, hence both c-j and Manley have been around for decades and keep going strong, must be doing something right...

Frankly speaking, I don't see the point of upgrading to KT150. Even the much trusted KT88 and 6550C are great sounding tubes for what they can do. It's just different kind of sound, and one that seems fuller, and for some may not be to their liking, hence the amps allow for the change. Whereas the KT150 requires a slightly modified circuit, I wouldn't know but one thing for sure is the amps I auditioned to so far having KT150's, didn't tickle me at all.and now Joe here mentions that his mate met the two legends themselves in Vegas, and nothing about a new KT150 design was spoken about or even thought of... well go figure.

Cheers Joe and Joe, which one is which...
Sorry, RJ
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by AudioDon »

Him all,
I know this thread is a few months old, and my reply is a bit off topic but here goes.

I just purchased a Premier 11, and am looking to do a few upgrades. I purchased a quad of KT-120's to liven the amp up a bit, and while they did tighten up the bass, the highs seems to be kind of dry and not as rich as the 6550's. Is there something I'm missing about the KT's?

And a quick comment to Big Dog, I heard a cut from a reasonably new Charlie Hayden/Gonzalo Rubalcaba release Toyko Adagio, and it's pretty darn sweet. It's worth a listen

Don
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by Joe Appierto »

Hi Don,

I've tried the KT120's in both a Premier 11A and a Premier 140, and although I know I'm in the minority, I also found them uninvolving. For my tastes the 6550 family and KT88/90/100 were superior. It's all system and user dependent but that's been my experience.

Regards,
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by Big Dog RJ »

Hey Joe, how's it going?
Trust all is well at your end of the woods.
Yes, totally agree! The premier11 is a true classic cj amplifier that is meant to be enjoyed in its full glory without trying to modify its sonic signature.

When I had the premier11A driving maggie mg3.5's I bi-amped the bass with ss monoblocks from parasound. not that great other a truck load of noise. then tried an Aragon stereo amp, things improved but still a mismatch. then tried a cj mf2300 and things greatly improved by a far margin but there was still a few areas a miss. eventually ended up with just the prem11a and with the pfr preamp, and all fell into place just nicely. even tried several versions of tubes, nothing seemed to improve the overall well balanced sound of the premier11a with just the 6550's. probably one of the best ampd I ever had.
you just have to love what it can deliver and that's about as good as it gets.
Cheers,RJ
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Re: Any thoughts if this will get me into trouble (KT-150 related)?

Post by Big Dog RJ »

Hey Don, thanks for that recommendation on charlie hayden, he is one legendary bass player.
ref to the premier11, nice to hear that you've got one! The premier11 is a very special amp. you really can't improve on it as cj finalized its design based on a previous circuit developed back then. The designs coming out now are newer so it allows for slight mods and allows for tube changes. Although the premier11 can take different types of output tubes, I didn't find any improvements whatsoever. The premier11 is meant to be enjoyed just the way it is. I am sure you will like it.
Cheers,RJ
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any one the schematic for the premier 140 ???

Post by petrix »

Hi there, does any one has a copy of a schematics for the amplifier premier 140 ?... to share with me pls???
thank you in advance!!
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Re: any one the schematic for the premier 140 ???

Post by admin »

petrix wrote: Tue Sep 25, 2018 11:29 am Hi there, does any one has a copy of a schematics for the amplifier premier 140 ?... to share with me pls???
thank you in advance!!
Martin Murillo.
Hi Martin,
Welcome to CJO. You can find our schematics here: https://www.conradjohnsonowners.com/vie ... f=17&t=128
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