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Samsung UE40JU6400 (JU6400) Ultra HD 4K TV Review

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Is 40 inches just too small for 4K?

by Phil Hinton May 4, 2015

  • SRP: £699.00

    What is the Samsung UE40JU6400?

    First of all it is an Ultra HD 4K TV with a resolution of 3840 x 2160 and in a surprising turn of events, especially for a new 2015 Samsung TV, it is also flat. There are no curves to be seen with the UE40JU6400 which should keep a certain part of the TV market (and some AVForums members) happy. The downside might however be the screen size as this is a 40-inch TV and it’s also an Ultra HD resolution screen. So will it work or is it just too small a screen size to see the extra detail on offer from a reasonable seating distance?

    Added to the UHD 4K screen is the new smart TV system called Tizen, 4K content streaming is also possible from Amazon and Netflix (internet speed dependent) and it also offers all the major on-demand services from the BBC, ITV, All 4 and Channel 5. So let’s take a closer look and see if 4K is worth it at in this segment of the market.

    Design & Connections

    Samsung UE40JU6400  Design & Connections
    The first thing you notice when unboxing the 40JU6400 is how light it is. The entire chassis is made out of plastic which makes lifting and moving the TV a piece of cake. The bezel is thin and plastic, but made to look like brushed metal. The JU6400 is also not the thinnest LED TV we have ever seen, with sections on the rear for speakers, electronics and connections. The stand slips into the bottom of the back plate and is screwed in to position. This means that the TV cannot be swivelled on the stand. We also thought that once stand mounted the TV still didn’t feel incredibly solid with quite a bit of twist, if moved. This might be due to the thin strip nature of the stand with only the central section having any real strength and bulk. However there is a neat cable run feature attached. Given the plastic nature of most of the JU6400’s construction, it still feels well-built.

    Samsung UE40JU6400  Design & Connections
    Around the back we have side and rear mounted connections. Chief amongst these are four HDMI inputs (MHL and ARC), three USB ports and the DTV aerial socket which are side mounted. On the back panel are the composite and component (shared) video inputs, stereo RCA audio in, digital Optical output, 3.5mm headphone jack and a LAN port.

    The UE40JU6400 also ships with just one remote control. This is a normal large plastic affair with the standard buttons well positioned and the most used easy to reach when the remote is sat in your hand. There are a number of ways to bring up channel information when watching digital TV, along with the EPG features. Navigation of the smart TV system is easily handled with the direction and enter keys, so it’s no great loss not having a remote pointer function like the smart remotes found higher up the range. Overall the remote is useful, well-proportioned and fits neatly in the hand.

    Features, Smart TV and Specs

    First order of business here is that the JU6400 is a 4K Ultra HD panel with a resolution of 3840 x 2160 on a 40inch screen. The question most people will obviously ask at this point is whether the screen size is just too small for users to get the benefit of the additional resolution over HD. The answer would be that over 6ft from the screen and most people with excellent eyesight would begin finding it difficult to pick out what was 4K and what was HD. As the panel used in the JU6400 is not HDR equipped nor does it have a much wider colour gamut than the normal Rec.709 standard, we are only talking about resolution as a difference between HD and UHD here. Is it worth having 4K at this screen size? I would normally give a few reasons for and against at this point, but the reality is that the industry thinks you do and they will be common place within the next 18 months, so I guess there is no real argument to be had. Within a very short space of time you will probably struggle to find a vanilla HD 40-inch TV given the speed manufacturers are starting to push UHD 4K forward in 2015.

    As this is a 4K Ultra HD TV it means that it has both VP9 and HEVC decoding so you can watch streaming services from Amazon Prime Video and Netflix (internet speed dependent). This is one area where the 4K streams can make some sense as they are better quality than the HD streams and approaching BD picture quality in most cases. Content is also being added all the time so the drought of 4K material, even if it is streamed, is improving. You can also feed native 4K material into the TV via the USB ports. I have shot a number of videos in 3840 x 2160 on a Panasonic GH4 and edited them in Final Cut Pro X where I could see footage at half resolution. On the JU6400 I could play back the edited videos in native 4K via USB and they looked stunning!

    The 40JU6400 also sports Samsung’s Ultra Clear Panel which minimises screen glare, reduces reflections and rejects ambient light spill on the screen. It also utilises a global dimming system for its LED backlight over the Smart LED local dimming systems found further up the product line.
    Samsung UE40JU6400  Features, Smart TV and Specs
    Samsung UE40JU6400  Features, Smart TV and Specs

    The Smart TV system for 2015 has had a major overhaul with the new system called Tizen. It’s a move away from full screen smart TV app pages and starts to resemble the WebOS layout seen on LG screens last year.

    All items on the JU6400, including source inputs, become apps in the system and allow easy navigation using a selection of cards which appear at the bottom of the screen. You can select or expand these cards to dig further down into the content you want or to simply change the source. From the initial home screen with the card layout you can select video on demand services, games, social apps and more. The system was also fast and stable during the time we used it, thanks to the Quad-Core processing and regular software updates which run in the background when ready to update.

    Services available on the Smart system include a full Samsung App store, catch up services from all the major UK terrestrial channels, 4K Netflix and Amazon Prime Video as well as Facebook, Twitter and other social media apps and games. We will have a full standalone review of the new smart TV system in the very near future, so stay tuned.

    UE40JU6400 Picture Settings

    If you intend to get the best picture quality from the UE40JU6400 we have suggested out of the box settings for Picture Mode (Movie), Colour Tone (Warm2) and Colour Space (Auto) along with contrast and brightness settings. In the video below we go through all these settings and also White Balance and Colour Space custom settings, but as always we warn against just copying settings, as they could make things look worse as each TV and viewing environment is different. We would suggest that you also follow our Picture Perfect Guide.

    UE40JU6400 Calibration

    As with almost every other Samsung review so far this year, the out of the box performance is very impressive when it comes to greyscale tracking and colour accuracy using the best picture mode (Movie) Colour Tone (Warm2) and Colour Space (Auto).
    Samsung UE40JU6400  UE40JU6400 Calibration
    Samsung UE40JU6400  UE40JU6400 Calibration

    As you can see in the charts we measured some excellent results for the out of the box settings chosen. Greyscale (white balance) is good with just a little too much blue in the lower reaches and a slight lack of green in the high end. However, looking at on-screen images and actual viewing material, there was no sign of any blue tint to the blacks or redness to the high-end. Gamma also tracked well and DeltaE errors were under 3, which meant that for most viewers they would not see any obvious errors by eye.

    The same was very true for the colour gamut performance with good luminance at all colour points and good tracking apart from blue, which while large on the graph error count, was almost impossible to pick out with on-screen reference footage. As some of the footage used as a reference point was 4K video that I had shot, edited and colour corrected, I could confirm the results were very accurate to how it should look.
    Samsung UE40JU6400  UE40JU6400 Calibration
    Samsung UE40JU6400  UE40JU6400 Calibration

    Calibration was just a case of tidying up the greyscale and colour results in the graphs, but also with known reference material on-screen. To be honest there was very little to do and there is even the argument that it probably didn’t really need doing either. With the greyscale using the two point was enough to get errors well below the threshold of the human eye (all under 1.5). We also managed to fix most of the colour points as well as get great tracking results from 25% to 100% which is pretty good going for a lower end 40” consumer screen.

    The best settings out of the box were extremely accurate, so much so that calibration was just a quick tidy up and not much more.

    Sound Quality

    As the UE40JU6400 is not the slimmest LED TV on the market it means there is at least some room for the speakers to work. At this screen size the TV is more than likely going to be used with the built-in speakers as a second set in the home, so sound quality will be important to most users.

    With that in mind the audio performance was passable as long as you don't push the volume too high with bass heavy content. There is not a great deal of stereo separation given the screen width here and as we mentioned, the bottom end is lacking. But with the majority of TV programs which are normally dialogue heavy with some ambient effects and background music, the JU6400 handled most material in a competent manner with nothing that stood out as being particularly nasty. However, if you can add an outboard audio solution, it will always be better than the performance from the TV here.

    Picture Quality

    Despite being the latest Ultra HD 4K resolution, the JU6400 LCD TV uses global dimming and not the advanced Smart LED local dimming seen on the higher-end 4K sets this year. There are no selection settings in the menus either so the performance has to be acceptable where we have no override and in the vast majority of cases it worked without any major issues. Only on a few demo clips did the screen dip to full off slightly too fast and in a noticeable jump of luminance. For the rest of our time testing we didn’t find the dimming to be intrusive when used as a living room workhorse.

    Black levels are impressive for an LCD LED but usually at the expense of fine shadow detailing during critical viewing. Only when watching reference material in critical viewing sessions in low light did this become the case as in usual ambient lit surroundings such detail wouldn’t be visible anyway. As this is a 40-inch screen sized TV it will likely be used in conditions and with material that have more flaws than any misstep from this review unit. Black levels were measured at 0.00cd/m2 with a 0% raster (backlit switches off and no way to stop this) and with the ANSI checker board we saw an average reading of 0.07cd/m2 (which is the more realistic result anyway). Contrast performance was more than acceptable from the JU6400 with a nice strong black level and when set up correctly, a good degree of detail in the highlights.

    With Blu-ray upscaled to the panel the JU6400 looked very sharp and handled the material perfectly thanks to excellent video processing. Motion handling with film content was also spot on with 24p material playing back without any induced judder. As mentioned earlier I played back 4K footage I had shot, colour corrected and edited, so I was very familiar with how it should look. It was played back via USB on the JU6400 and looked stunning at my normal seating distance of 5 feet. It was possible to pick up on the detail in the image, the strong and accurate colours of the glacial lake water and the gradations in the sunset were excellent. Even moving to Amazon Prime UHD streaming there was a good deal of visible detail at that distance. Moving back further and it becomes harder to define between HD and UHD at this screen size.

    Detail is strong and colour accuracy is excellent out of the box and calibrated, with very good blacks on offer as well. So, it’s all excellent then? Well, for the most part, and in daily use as a living room work horse, it will do very well.

    When it comes to more critical viewing in lower light levels things are not absolutely perfect, but again that is the LCD LED technology and not just this TV. In terms of screen uniformity at lower luminance levels we did notice some light pooling in the bottom corners of our review set. Again this was not visible during 90% of the viewing we did with this set in our living room, but when in low light and with low light material it was there. Gradations were for the most part very good with no visible banding seen at normal viewing distances and with football (large area of the same colour) we didn’t notice any obvious backlight striping or dirty screen effect.

    The biggest negative of the UE40JU6400 are the viewing angles on offer. Sat dead on axis the image looks fantastic, but moving off axis by only 10 degrees and things start to fall apart. Get wider than that and you completely lose image integrity, luminance, colour balance and blacks. It becomes very washed out, very quickly, so please test this if you plan on corner placement of this screen in your home. Again, this is another trait of the technology used and the panel selected.

    How future-proof is this TV?

    4K Ultra HD Resolution
    HDR Support
    Colour Space (percentage of DCI - 100% best) 50%
    10-bit Panel
    HDMI 2.0a Inputs
    HDCP 2.2 Support
    HEVC Decoding
    4K Streaming Services
    Smart TV Platform
    Picture Accuracy Out-of-the-Box (score out of 10) 9
    What do these mean?


    OUT OF


    • Excellent out-of-the-box accuracy
    • Great colours and onscreen contrast
    • Impressive video processing
    • Good black levels and shadow detail
    • Low input lag
    • Nice UI and Smart Features


    • Narrow viewing angles
    • Too small for serious UHD unless you sit really close
    • Lip Sync issues with Firmware1203 and Freeview HD tuner
    • Some small issues with dirty screen and some small uniformity issues
    You own this Total 8
    You want this Total 1
    You had this Total 0

    Samsung UE40JU6400 (JU6400) Ultra HD 4K TV Review

    The UE40JU6400 is one of the first LED LCD TVs to offer 4K Ultra HD on a 40inch screen, but it certainly won’t be the last. This will likely become a large sector of the market as we move forward whether we think it's worthwhile or not. In truth you have to sit at the very most 5ft back from the JU6400 to still be able to see the extra detail on offer with native 4K material. Any further back it becomes more difficult to tell the difference in resolution alone. And as this panel is not a wider gamut or HDR capable one, then resolution is the only comparison to be made.

    The JU6400 is however very accurate out of the box for both greyscale and colour gamut, and given the price it retails at, that is a positive as a full calibration would only tidy up the graphs if the performance here is repeated with other JU6400s. Viewing angles may be restrictive, but sit on-axis and the black levels, shadow detailing and contrast are very respectable indeed when added to the accurate colours. Native 4K looks stunning and motion resolution is also good. Switch to Blu-ray or HDTV broadcast and it continues to perform well with excellent processing. Standard definition is also well represented and a good quality feed will stand up well enough. There is no 3D on-board and in most cases we don’t think it will be missed.

    The new Tizen Smart TV system is also extremely well executed with a good selection of apps which are not just Samsung branded or focussed, but offer a good choice of extras. You have all the major TV catch up services available as well as 4K Netflix and Amazon Prime video services depending on your internet connection. Plus there are also special interest and social media apps.

    Whilst there is no such thing as a perfect TV and there are a few minor niggles with the JU6400, but, overall given the screen size, price point, build quality and features, we think it makes a good case for your consideration as that smaller second room screen and as such it comes recommended.

    The Rundown

    Contrast/Dynamic Range/Black Level


    Screen Uniformity


    Colour Accuracy


    Greyscale Accuracy


    Video Processing


    2D Picture Quality


    Picture Quality Out-Of-The-Box


    Picture Quality Calibrated


    Sound Quality


    Smart Features


    Build Quality


    Ease Of Use


    Value for Money




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