Approaching the highest peak of DIGA "ZR1" over UB9000. A must-have item for AV lovers !?

All "because it exceeds UB9000".Elimination of analog output, review of power supply and circuit

The ZR1 is a premium model of DIGA that inherits the genealogy of the world's first UHD BD playback compatible BD recorder "DMR-UBZ1" released in 2015 and the UHD BD player "DP-UB9000" released in 2018. The premium class BD recorder will be on sale for the first time in 6 years since UBZ1.

The ZR1 was developed by the DIGA team, which also worked on successive BD recorders and the above-mentioned UBZ1 and UB9000. With the slogan of "Making the best 4K player", the members who created the UB9000 took three years to complete it with the goal of "the definitive 4K recorder, the ultimate 4K recording / re-machine".

DMR-UBZ1DP-UB9000DMR-ZR1

Mr. Kono, who has been involved in the development of high-end models of DIGA for many years, said, "4K content such as broadcasting, packaging, and VOD has been enriched, and an environment where you can enjoy AV experiences beyond movie theaters at home is being prepared. What is needed in such a situation is a product that can handle all 4K contents with the highest quality. DNA that has been cultivated through 15 years of technology accumulation of Blu-ray DIGA since 2006 and collaboration with high-end DVD players, UniPhier, Hollywood, and Technics. By making the best use of this, we aimed to create a 4K recording / replay machine that greatly exceeds the playback performance of the UB9000. "

Regarding the fact that it was not equipped with an 8K tuner, Mr. Kono said, "Currently, it is still 4K that we can make the best use of our technological assets. For example, even if we try to decode an 8K broadcast stream, it is now. This is not possible with the chips used in DIGA. Handling 8K requires different technologies and know-how. On the other hand, 4K is now maturing, saying, "We have fully introduced the technology we can have. I want to make the best product once. If I do it now, I have to do it now. "

In developing the ZR1, there are three design concepts.

Among them, "basic image quality / sound quality exceeding UB9000" was the biggest issue.

"Even if an all-in-one 4K recording / re-recording machine can be made, there is no point in making it with a" model whose quality is not comparable to the UB9000. "On the other hand, we have almost completed the quality improvement in digital AV signal processing with the development of the UB9000. Therefore, in order to exceed the reproduction quality of the UB9000, it was necessary to take a different approach than just signal processing, "said Mr. Kono.

Therefore, the DIGA team worked on an "analog approach" that drastically reviewed the power supply, electric circuit, and housing. In order to exceed the UB9000, a method was adopted in which each circuit was thoroughly brushed up while eliminating the analog audio board including the audio DAC and the analog dedicated power supply and concentrating the quantity on the digital / drive power supply.

Then, what exactly is the high image quality and high sound quality design adopted in ZR1?

First of all, the housing inherits the structure and base chassis of the UB9000 released in 2018.

The chassis that supports the bottom uses a heavy-duty base chassis with a total thickness of 4 layers and 6 mm and a weight of 5.6 kg, which is made by laminating 1.6 mm thick x 3 layers of steel plates on a 1.2 mm thick steel plate inner chassis. Along with the high carbon cast iron insulator, the center of gravity of the housing has been significantly lowered, and unnecessary vibration has been reduced.

ZR1 internal structure 7mm thick front panel

The front panel is equipped with a special member that has been machined based on a 7 mm thick extruded aluminum material. 3mm thick aluminum extruded material is also used for the side panel, and by fixing it to the base chassis from the front and side, the rigidity of the housing is strengthened. Vibration damping has been improved by assembling two-layer steel plates with different thicknesses on the top panel.

For UHD BD drives, which are a large source of vibration, mount them on a drive base that uses a 3-layer 5.2 mm thick steel plate. In addition, by covering the entire drive with a high-rigidity shelter made of deep-drawn steel plate, unnecessary vibration and noise during disk rotation are suppressed. Furthermore, the drive is placed in the center of the housing, and the rigidity is strengthened by fastening the two frames integrated with the drive base to the front panel and rear panel mentioned above.

UHD BD drive and 3-layer base HDD and 2-layer base

Like the UHD BD drive, we have newly developed a dedicated drive base for HDDs. By pasting two types of steel plates (3.2 mm thick + 0.8 mm thick) with different thicknesses and directly attaching and fixing the HDD to the dedicated drive base, vibration due to rotation is greatly reduced. All the built-in HDDs have been inspected, and low-speed type HDDs are being selected.

Internal structure of UB9000 Internal structure of ZR1

According to Mr. Miyamoto, who was in charge of sound quality design, it was the "independent power supply" that was the key to raising the basic sound quality and image quality.

"The power supply of the UB9000 consisted of an analog-only power supply and a digital / drive combined power supply. The ZR1 eliminates the analog-only power supply and separates it into a digital-only power supply and a drive-only power supply. It led to noise reduction from HDD to digital system. " Mr. Kono also said, "The first thing we started with was an independent power supply. It was very important to review the power supply, and when we saw the improvement in the image quality, we got a response that exceeded the UB9000."

Digital drive independent power supply

The circuit board, which occupied 1/3 of the area in the UB9000, concentrates the surplus circuit resources in the digital system in the ZR1.

For the system clock, an ultra-low phase noise crystal oscillator, a local regulator to take advantage of its performance, and a chip film capacitor with good high frequency characteristics (generally a grade used around DA converters) are used. Even for AV clocks, we have achieved a thorough low clock jitter design by adopting an ultra-low jitter PLL, a local regulator, and a chip film capacitor.

The ultra-low phase noise crystal oscillator, which has an improvement effect of about 15 dB compared to the UB9000, is said to have export restrictions on parts that are treated as military diversion due to its high performance. I adopted it "(Mr. Miyamoto).

High precision clock circuit

In addition to the USB front of the UB9000, the "USB power conditioner circuit" using a ruby ​​mica capacitor and a non-magnetic carbon film resistor is also used in the USB rear and two HDMI power supply circuits in the ZR1 to ensure thorough noise countermeasures. Also, by adding a chip film capacitor and chip beads for reducing high frequency noise around the HDMI output circuit, wraparound noise from display equipment is suppressed.

USB power conditioner circuit HDMI output circuit

The LAN terminal has also been brushed up for the purpose of improving the quality of online videos. Conventional models such as the UB9000 used the oscillation circuit included in the Gigabit Ethernet IC, but the ZR1 is equipped with an external ultra-low jitter crystal oscillator, and a local regulator and chip for supplying low noise power to it. A film capacitor was used.

LAN terminal

In addition, the coaxial digital audio output circuit uses an output transformer equivalent to the Technics high-end model (SU-R1) and a machined brass terminal. The output performance is enhanced by separating it from the chassis GND where high-frequency noise wraps around.

Mr. Kono recalls, "These reviews of power supplies and circuits were mainly focused on improving sound quality, but as a result, they also contributed significantly to improving basic image quality."

Coaxial output circuit Various high-quality sound parts used in power supplies and digital circuits