"Hi-End, Not High Priced" ...... Best Value Chinese Hi-Fi

Due to excessive shipping damage cases on this product, we have decided to discontinue carrying this product until the product can be improved for durability or shipping method is improved.

Just released in Dec 2008 after 3 years of research! TJ Full Music has spent the last 3 years to conquer the technical bottleneck in the design of 805/845/211 series and now accomplished the MKII version.

Compared to other brand same model tubes or even the previous TJ tubes, the designer has chosen to use carbon plate instead of graphite plate in the MKII version to dramatically improve the life expectancy and reliability of this particular model of vacuum tube.

About TJ 845 vs. RCA NOS 845 specs:

TJ Full Music 845 MKII is rated with 'nominal filament current - 0.6A at 10V' while the original RCA 845 tube was rated "filament current - 3.25A at 10V'. According to TJ Full Music's tube designer, for 845 tubes made with carbonized Thoriated Tungsten such as the RCA NOS 845 tube, filament current of 3.25A is required to generate sufficient electron emission for the tube to work properly. However, TJ Full Music's 845 MKII uses oxide coated filament which doesn't request as high as 3.25A filament current to generate sufficient electron emission.

For manufacturers or Diy-ers who deisgn their own 845 tube amplifier, they can design the amplifier to RCA 845 specs but with simple adjustment can still be able to use the TJ Full Music 845 MKII tubes.

Again as per TJ Full Music tube designer, the previous TJ Full Music 845 MKI version tube did encounter certain longevity problem and some have been recalled by the manufacturer. However, such longevity problem was caused by insufficient vacuum inside the tube, not by the relatively low filament current (0.6A vs. 3.25A). A vacuum tube's lifespan is determined by many factors. For a 845 tube's lifespan, the operating plate voltage, not the filament voltage, is one of the key factors. To allow your TJ Full Music 845 MKII tube work to its longest possible lifespan, manufacturer strongly recommends that the operating plate voltage no higher than 1,250V in any circumstance. It is recommended to design the amp with tube plate voltage 925-950V and filament current optimized at 60mA to 70mA.

For consumers who own a 845 tube amp, it is highly recommended to check with your tube amp manufacturer to see if the TJ 845 MKII tubes will work with your amp design at the optimal condition by providing the tube full technical specs to them. For safety reasons, it is strongly recommended not to attempt to adjust any settings on the tube amp by yourself unless you are a certifided technician!

The TJ Full Music 845 MKII tube has passed the torture-test of 90+ days around the clock with power on - it is proven with reliability, longevity and performance.

Grant Fidelity is the first North American distributor who carries TJ 805/845/211 MKII series. All tubes are factory matched premium with 30 days warranty included in the listing price. 12-months warranty is at extra cost as stated.

Check out Grant Fidelity Picture Gallery to see the production picture of TJ Full Music and meet the owners! :-)

The following link is to TJ Full Music's official site with complete technical specs for this tube:

http://www.tube-fullmusic.com/products/en-product0-845.htm