KT120 Vacuum Tube from Tung-Sol

[Raj J]

greetings to all from Melbourne!
trust everyone is enjoying their music and keeping fine.

Just got hold of the KT120 output tubes last Wednesday, replaced the 6550c tubes on my conrad johnson power amp; "WOW!"
1. Tremendous expansion on the soundstage
2. Remarkable overall sonics, very well balanced.
3. Awesome bottom end, far more bass information I have ever heard so far from systems that I have owned and heard...
4. Highs are smooth, very easy to listen to, mids are just glorious, coming from Quad ESL's the midrange is even more special, and the bass is phenomenal!
5. The overal presentation is a true live performance, live scale easily achieved, no strain whatsoever! Obviously it is driving my ESL's quite easily, and the power amp is well matched with the ACT2 preamp.

weaknesses: nothing major that I could possibly think of other than, the tubes are fairly larger than the 6550's or KT90's, therefore make sure if you are changing tubes your amp can fit them well with plenty of headroom and space around the tubes. some amps will not be able to take the extra size of these beauties. The MV60se seems to have been made for KT120's because they fit just perfecty even with the tube cage on.

For those of you who are using either 6550, KT88, KT90 or similar, try out these new KT120's you will NOT be disappointed. To me they are like a combination of the best midrange an EL34 can give, the power and finesse of a KT90+6550 put together and the robust full presence of the KT88. They are simply Awesome!

The other fantastic thing is that my MV60se is not even wired to get the best out of these gems, therefore they are pretty much half asleep and still perform wonders. I was told that this lengthens tube life and they can certainly out last 6550's to nearly double the usage hours. I have yet to try an amplifier that is actually designed for KT120's, then we are talking. For now, I'm just heading home to invite Diana Krall and some friends over, Esparanza Spalding for some late tea... enjoy your music, this is truly an amazing tube.
check it out!

associated system:
preamp: conrad johnson ACT2
poweramp: MV60se
speakers: Quad ESL 2905
source: vacuum tube CD player from Cayin
cables/interconnects: DHLabs Q-10 & Silver Sonic Air Matrix
power conditioner: Thor PS10 by Nordost
magnetic field stabilizer: Quantum Qx4 by Nordost
audio rack: Apollo Designs, pure glass.

cheers, Raj J

[Jack in Wilmington]

Thanks Raj, I have a Jolida with 6550's and I will definitely be checking out a set of the KT120's. I was thinking EL34's but this is another way to go.

[Raj J]

Thanks Raj, I have a Jolida with 6550's and I will definitely be checking out a set of the KT120's. I was thinking EL34's but this is another way to go.

yes, EL34's are excellent tubes no doubt, very musical and wonderful soundstage. However, if your Jolida is currently designed for 6550's, can you replace them directly with EL34? I would have thought that tubes compatible with 6550's and the like are ok for direct swapping, but with EL34's it may require circuit modifications... I maybe wrong with the Jolida, I'm not too sure.

Anyway, if you are considering the KT120 I would say go for it! The whole musical experience is just remarkable; all of what I have mentioned. The KT120 will just breathe new life on a very realistic live scale if that is what you are after!

There are many music lovers and audiophiles who may prefer the 6550 tube, hence extensively used by Audio Research & Macintosh, VTL & the like... I have extensively listened to a wonderful pair of 120 watt monoblocks in bi-amp config (special edition custom built) by Audio Research driving Apogee Diva's. That sound was probably the best overall at the time, and the most musical I experienced- all output tubes were 6550's.

Comparing that system to my current one, I don't have that type of power and slam, because Quads are certainly not designed that way. However, in relation to the absolute sound c-j & Quad are probably the closest approach, and with this KT120 and the ACT2 preamp the live scale is effortless. Very simple setup no massive monoblocks or gizmos, well laid out and cables/interconnects kept to short as possible, the synergy is top notch. Another important factor is addition of the Qx4 by Quantum Technologies, distributed through Nordost. I truly believe that this is a "must have" component in any system regardless of price! If you have not tried either the Qx2 or Qx4, please try to get hold of one and you will be yet amazed as to how the soundstage clears up nice and smooth with that special true to life 3-D effect. Each & every musician is doing their bit and sitting right next to you! The best part is that the sound fills your entire room with ease and finesse, and at one point you cannot tell whether you are actually on the stage or not...

This is what I am currently experiencing, and I guess I will stop for a lttle while and let all settle in. Cannot think of any significant upgrades, other than the Cayin vacuum tube CD player. Then again if it is sounding so fantastic why upgrade.
Take it easy and have a good one!
Cheers, Raj J

[Feanor]

Wow! Mr Peabody might yet be tempted to roll some tubes on his CJ gear.

Thanks for the update, Raj.

[poppachubby]

Tung Sol are one of the best when it comes to current production tubes. I have a set of their 6L6 GC STR which are every bit as wonderful as Svetlana's Winged C, just not as expensive.

[bobsticks]

Conrad Johnsons and Quad ESLs...sounds like a match made in heaven...definetely some serious system matching going on there. Cheers on finding an improvement on what is already a strong setup.

I'm unfamiliar with the Cayin cdp. I'd be interested to read your perceptions as to what it adds...continued analog refinement or a little digital top end sizzle...?

In any case, thanks for sharing.

[Raj J]

Conrad Johnsons and Quad ESLs...sounds like a match made in heaven...definetely some serious system matching going on there. Cheers on finding an improvement on what is already a strong setup.

I'm unfamiliar with the Cayin cdp. I'd be interested to read your perceptions as to what it adds...continued analog refinement or a little digital top end sizzle...?

In any case, thanks for sharing.

No worries, Cheers!
the Cayin brand has been around for many years; Prima Luna is also made under the same factory, and carried with the same distributor. The history of Cayin originates somewhere in Germany, and is now made in China alongside Prima Luna; quality is top notch stuff! inside and out they make some serious gear that was well reviewed in TAS during 2010. they had reviewed several products by Cayin including the same CD player I am using. It is solidly built and very stable, you could place a power amp on top of it if need be...

Back in 2001/2002 I was using a conrad johnson top of the line CD player called the DV2b vacuum tube design. it was a glorious unit, and one that I still miss! I had to give it away when I migrated over to Australia; therefore it took me nearly 5 years to find something that was nearly as close, and the Cayin CD50T seems to be quite a good match. Of course I am waiting for c-j to put out their new digital playback systems, maybe a transport / DAC separates, don't really know what's next in line...

Their McCormack CD player called the DP2 is not bad, but the price difference from the Cayin is a big step (3 grand more), hence not worth the extra spend. I might as well wait for c-j's next arrival. I did have my eyes on the new Cary 303T but the dealer who offers it in Melbourne is not someone that I would associate with. Dealers to me are very important, that's why I have a solid business relationship with mine, Caxton Audio/Sound Reference in Melbourne. I've been with them since 2005! Wonderful people to do business with.

I was thinking of going vinyl - turntable, cartridge, arm, phono stage etc, etc... far too many CD's to throw away. might as well stick to digital for now...
I do understand though why so many music lovers and audiophiles love their turntables, they are without a doubt the best possible source equipment! Although the digital age is improving each day, someday soon it will get there who knows?

Have a great weekend and enjoy your music.
cheers, Raj J

[E-Stat]

I have yet to try an amplifier that is actually designed for KT120's...

Indeed. Changing tubes can alter the voicing. While you are pleased with the result, I would not swap the 6550s in my VTL amps for KT-88s as they sound "tubish" in them. Yet KT-88s sound neutral in the McIntosh 2301s. Audio Research just announced the REF 150 which is designed from the outset around the KT-120s. Ironically, the tubes are less expensive than the SED 6550Cs used in my MB-450s. It would be interesting to try them out, but it would be a costly experiment since I need eight pairs.

rw

[Raj J]

Indeed. Changing tubes can alter the voicing. While you are pleased with the result, I would not swap the 6550s in my VTL amps for KT-88s as they sound "tubish" in them. Yet KT-88s sound neutral in the McIntosh 2301s. Audio Research just announced the REF 150 which is designed from the outset around the KT-120s. Ironically, the tubes are less expensive than the SED 6550Cs used in my MB-450s. It would be interesting to try them out, but it would be a costly experiment since I need eight pairs.

rw

Yes, you would require 8 pairs; I did the same thing when I had those massive Manley reference 350 monoblocks from VTL. They previously had 6550's and I did a complete tube replacement with KT90's. The change was well worth it! I was driving maggies and Infinities thereafter, the KT90's did a fantastic job!

Don't get me wrong the 6550c is an excellent tube, infact conrad johnson and Audio Research swear by it, hence it's being around for decades...
But this KT120 is a very special tube indeed. I don't know what exactly it does and I had my doubts about using it at first since I have always trusted & used 6550's. I guess it's also to do with the circuit, if it is simple and can handle the properties of the KT120 then I would think it would work fine. It is not like a KT88 or any of the other KT series. It is way beyond any of those put together. What I get is a mix of EL34 magic, KT90 power and 6550 finesse all in one. My c-j power amp (MV60se) is only rated at 60 watts, now with the KT120's performs more like a 120 watter! I also think a lot of it has to do with the c-j ACT2 preamp. It matches extremely well with the power amp and drives the Quads effortlessly to full live scale levels. Again it's all do to with synergy and component matching.

Therefore I guess you would have to carefully match your tubes before trying anything out. You would also have to turn down the bias before installing just to be on the safe side. But one thing I do know is that my Manley 350's worked very fine with KT90's, so KT120's should work as well and even better! It is an adventure afterall...
I am sure your VTL's will deliver a performance that you have not yet experienced.
Ask Luke and see what he has to say...

Cheers, RJ

[E-Stat]

I also think a lot of it has to do with the c-j ACT2 preamp. It matches extremely well with the power amp...

That is exactly my concern. Since my system doesn't require a line stage, there is no need for me to change the voicing of the output tubes to match another component's personality.

rw

[Poultrygeist]

I just picked up a $30 quad of 5670 Tung Sol preamp tubes for my new 2a3 SET integrated amp. They are only slightly surpassed by the WE 396A which go for upwards of $200 a quad!

[Raj J]

no problem at all for those of you who want to retain the same output tubes as recommended by the manufacturer, keep what you have; I am sure you are enjoying your music!

For my system since I have spent nearly a fortune (well over 50 grand) accoridng to my means; a couple hundred bucks transitioned me to a place that I haven't experienced before, and it was the change of output tubes, so I thought that Id share this experience with others who may be interested in the attributes of the KT120. Whether it is changing the voicing or not, I don't bother about that region, since the overall performance is a dramatic improvement. I was told that the c-j circuit is a very simple one, and one that works quite well with different types of output tubes provided they are compatible.

If it was a marginal improvement, I wouldn't be making such a noise...
There is another customer here who did a smilar change with his c-j LP66s amp, and is wondering why they didn't think of the KT120 before, that's because it was not around until recently. He's absolutely loving it!

Anyway, it is upto you, only your ears can be the judge of that, so if you are enjoying what you have, be it a tin box or 100 grand system, good on you! That's all that matters at the end of day, you should be able to relax and enjoy your favorite music through your system in a way it was intended for.

As for me it is now 6pm, just about to shut down the office heading home and this time George Benson and Miles Davis are coming home for tea!
Have a good one all!
cheers, RJ

[E-Stat]

no problem at all for those of you who want to retain the same output tubes as recommended by the manufacturer, keep what you have; I am sure you are enjoying your music!

Thanks for the heads up. I'll stay tuned to what Luke Manley does. The tube draws 100-300 mA more filament current than a 6550. The third generation MB-450 was in use by a number of manufacturers at recent shows and I'm leery of a more "tubey sound" as reported by others: Another review.

rw

[Feanor]

Thanks for the heads up. I'll stay tuned to what Luke Manley does. The tube draws 100-300 mA more filament current than a 6550. The third generation MB-450 was in use by a number of manufacturers at recent shows and I'm leery of a more "tubey sound" as reported by others: Another review.

rw

By the way, I'd really like to hear a Bob Latino ST-120 in my system. For the money, they's be a semi-realizable dream for me, assuming I liked them.

The AA reviewer did allow that the Tung-Sols were probably not fulled burned-in. But assuming what he said is valid overall, I'd rather have the "air" than the "fuller" bass.

[Fred70433]

I was thinking about the Shugaung Treasure KT-88's for my Jolida 502B. Not that I'm unhappy with the stock Tung Sol 6550's, but I was wondering if they might lower the noise floor a bit.

Also, what's the bias for the KT-120'S? How much "bigger" are they than the 6550's?

[Jack in Wilmington]

I was thinking about the Shugaung Treasure KT-88's for my Jolida 502B. Not that I'm unhappy with the stock Tung Sol 6550's, but I was wondering if they might lower the noise floor a bit.

Also, what's the bias for the KT-120'S? How much "bigger" are they than the 6550's?

I was wondering that also. I was useing the Audio Research DSi200 over the weekend and it uses the 6550 tubes. It was nice to be throwing 200w at my Dynaudios. Sounded sweet.

[Raj J]

regarding direct comparison to KT88 and 6550's bias requirements; I am not familiar with the bias current required for the KT120's simply because my conrad johnson does not require biasing, only a slight adjust with a led indicator...

for those of you out there using a multi-meter to actually bias your output tubes, you will have to check with the KT120 spec sheet and find out what the exact bias is required in Milli apms/or volts. I would also check on the net as they have the bias requirements for the KT120's, another area to look for would be to ask TungSol directly.

I do know the current milli amp requirements for the 6550's, KT88's & KT90's when I was using Manley monoblocks which required individual bias with a multi-meter, but now that I am using conrad johnson amps it doesn't require such biasing.

in terms of size, the KT120's are much larger than KT88, KT90's and slightly fatter and much taller than 6550's. if you are using a tube cage or top cover, make sure that there is enough headroom as not to touch the tubes in anyway during operation. they also dissipate about the same heat as 6550's but this is because the circuit they are currently in was originally designed for 6550's and not KT120's. therefore, they are probably just cruising along with absolutely no stress...

please check out the specs and dimensions of the KT120, they are available on-line and TungSol are happy to answer your questions.
hope this hepls!
cheers, Raj J

[Raj J]

Regarding direct comparison to KT88 and 6550's bias requirements; I am not familiar with the bias current required for the KT120's simply because my conrad johnson aamp does not require biasing, only a slight adjustment with a led indicator is all that is required...

for those of you using a multi-meter to actually bias your output tubes, you will have to check with the KT120 spec sheet and find out what the exact bias is. I would also check on the Net as they have the bias requirements for the KT120's, another area to look for would be to ask TungSol directly.

I do know the bias current requirements for the 6550's, KT88's & KT90's when I was using Manley monoblocks, which required individual biasing. However, now that I am using conrad johnson amps it doesn't require such biasing.

In terms of size, the KT120's are much larger than KT88, KT90's and slightly fatter and much taller than 6550's. if you are using a tube cage or top cover, make sure that there is enough headroom as not to touch the tubes in anyway during operation. they also dissipate about the same heat as 6550's but this is because the circuit they are currently in was originally designed for 6550's and not KT120's. therefore, they are probably just cruising along with absolutely no stress...

Please check out the specs and dimensions of the KT120, they are available on-line and TungSol are happy to answer your questions.
Hope this hepls!
cheers, Raj J

[Raj J]

Sorry folks, seems like my message had posted twice...

By the way did some serious listening last weekend to both sets of tubes (KT120 & 6550C). KT120 TungSol & 6550C Svetlana Electron Devices.

These were my findings:
1. For a quiet relaxed listening session, soothing music such as a jazz trio, solo violin, piano & voice, or small ensemble etc. the 6550's were warmer in terms of smoothness and relaxation. Although the KT120's are well capable of delivering this, they take sometime to get kicking and this leads to point 2 below;

2. For a true live impact of fantastic dynamics, speed and power the KT120 has it all! Plus more detail & definition especially in the bass and highs, midrange is somewhat equal.

Both sets of tubes have a magnificent soundstage, 3D at its best no doubt! However, the one thing I noticed was the playback levels. The 6550's soundstage was all neatly in place and sounded just right at any given level wihtout too much added punch. Altering volume levels did not impact the scale immensely, hence remained the same throughout.
The KT120 is a bit laid back at very low volumes, turn it up a bit and it's a whole new level of realism!

Summary: both are equally very nice to listen to for endless hours without any fatigue and will produce the absolute sound. In terms of having all the virtues of the KT series, EL34 and 6550's put together, the KT120 would be my first choice.
Just to have as a second set of tubes enjoying a slightly different kind of sound, the 6550c is a wonderful tube to have and one that can easily be a pleasure to listen; either way both are excellent for a high resolution soundstage, and one that is captivating from low to moderate levels or late night listening sessions (which I do most of the time).

That's about it, hope the music lovers out there have experienced the new KT120 the same way... trust you are not disappointed.
cheers and enjoy your music! RJ

[Raj J]

Sorry folks, seems like my message had posted twice...

By the way did some serious listening last weekend to both sets of tubes (KT120 & 6550C). KT120 TungSol & 6550C Svetlana Electron Devices.

These were my findings:
1. For a quiet relaxed listening session, soothing music such as a jazz trio, solo violin, piano & voice, or small ensemble etc. the 6550's were warmer in terms of smoothness and relaxation. Although the KT120's are well capable of delivering this, they take sometime to get kicking and this leads to point 2 below;

2. For a true live impact of fantastic dynamics, speed and power the KT120 has it all! Plus more detail & definition especially in the bass and highs, midrange is somewhat equal.

Both sets of tubes have a magnificent soundstage, 3D at its best no doubt! However, the one thing I noticed was the playback levels. The 6550's soundstage was all neatly in place and sounded just right at any given level wihtout too much added punch. Altering volume levels did not impact the scale immensely, hence remained the same throughout.
The KT120 is a bit laid back at very low volumes, turn it up a bit and it's a whole new level of realism!

Summary: both are equally very nice to listen to for endless hours without any fatigue and will produce the absolute sound. In terms of having all the virtues of the KT series, EL34 and 6550's put together, the KT120 would be my first choice.
Just to have as a second set of tubes enjoying a slightly different kind of sound, the 6550c is a wonderful tube to have and one that can easily be a pleasure to listen; either way both are excellent for a high resolution soundstage, and one that is captivating from low to moderate levels or late night listening sessions (which I do most of the time).

That's about it, hope the music lovers out there have experienced the new KT120 the same way... trust you are not disappointed.
cheers and enjoy your music! RJ

[Groovydude]

By the way did some serious listening last weekend to both sets of tubes (KT120 & 6550C). KT120 TungSol & 6550C Svetlana Electron Devices.

These were my findings:

Both sets of tubes have a magnificent soundstage, 3D at its best no doubt! However, the one thing I noticed was the playback levels. The 6550's soundstage was all neatly in place and sounded just right at any given level wihtout too much added punch. Altering volume levels did not impact the scale immensely, hence remained the same throughout.
The KT120 is a bit laid back at very low volumes, turn it up a bit and it's a whole new level of realism!

Wow I really enjoyed this whole discussion and pardon my ignorance as I'm just getting back into a system, and I just picked up a pair of the VTL MB-450s the first gen style built around 2010 from a nice lady that never pushed them out of tetrode, however she had her tube head friend put in a fresh set of the KT-120's And kept them biased and loved the sound of them. Well today I called VTL to see if there were any upgrades available for the amps and mentioned to Bea(I think was her name, nice lady) that I had the KT-120's and it went over a bit like a fart in church,she said that they don't recommend those etc. As these are brand new to me,just got them today and haven't had time to set up just wanted to make sure that I'm not going to damage these Amps in any way by running them, as also I don't have the cash to grab 16 good 6550's to swap out at the moment anyways. So advice? Thanks

[E-Stat]

... just wanted to make sure that I'm not going to damage these Amps in any way by running them, as also I don't have the cash to grab 16 good 6550's to swap out at the moment anyways. So advice? Thanks

Well, you may just. Especially if VTL says they're not recommended!

As I indicated earlier, they are NOT a direct drop in for the tubes for the 6550/KT88 since they draw more current. I don't know what to suggest other than checking first before making changes.