Loading... Please wait...Tung-Sol KT120 - Super cool KT88 variant made by New Sensor in Russia. This tube is a drop-in replacement for KT88s... no special re-wiring required! The KT120 is rated to have a plate dissipation of 60W... compared with the 35W of the 6550, the 42W of the KT88, that's a lot of juice!
The KT120 also draws more current from your amp's output transformer(s). Before you buy them, check with your amp's manufacturer to make sure you've got enough headroom.
One quick note: The KT120 is about 1/2" taller than a typical KT88, so if your KT88s are already a tight squeeze in your equipment, you may want to measure to make sure you have enough clearance before placing an order. If you have a PrimaLuna or Mystere amp, you have to keep the tube cage off to use these.
As the distributor for PrimaLuna and Mystere amplifiers, we do not recommend this tube.
Pricing above includes matching in any quantity you need at no extra charge.
All power tubes are Platinum Screened & Tested to the highest standards, including a 72-hour burn in process, and testing at real-world voltages.
Posted by Joe
Even response along the frequency range with an extended top that’s not bright. Soundstage is very good. I didn’t find them to be obviously more powerful, however, there’s an effortlessness to their sound with a wide dynamic range that maybe tells the real story. Among current production tubes the Tung-Sol Reissue 6550s are among my favorites and to that small group I’d have to add these KT-120s. I’d purchase them again. (This review is based on listening to eight of them in a conrad-johnson Premier 140 amplifier over QUAD ESL-989 speakers.)
Most of you already know that Upscale Audio is the premier destination for expertise and availability of vacuum tubes for high-end audio equipment. So when we offer servies and options, you can be guaranteed that it represents a significant investment of research and capital, and that the end result will greatly enhance your listening experience.
Upscale has contracted with the foremost company involved in this technology, 300 Below, to treat our most popular tubes. Other tubes will be added as time allows, but it is a time consuming proccess. Our intention is to have most stocks Cryogenically treated before we even test them.

Of course, your first question is – and should be – why? In a nutshell, reducing an object’s temperature to -300ºF re-arranges its molecular structure, creating greater uniformity that results in longer life and better performance than when the product was initially designed.With vacuum tubes, this process has a profound impact on a tube’s ability to endure thermal shock. Therefore, tubes can last longer and their sound can been enhanced in ways that are simply exquisite.
After thoughtful and thorough research, Upscale Audio chose 300 Below because of their extensive experience in working with musical instruments as well as auto racing, metal tooling, and high-end sporting goods from rifle barrels to golf clubs. Expect nothing but the best from Upscale Audio.
Our charge for Cryogenically treating tubes is a fraction of what others charge, though we use the premier company. Count on Upscale to do the best job and not price gouge . Also available is cryogenic treatment for cables, along with our well-known Nordost Vidar cable treatment system. Call for details. Pricing is listed on each tube and cable page.
Vacuum tubes are warranted for 90 days against defects, except in cases of abuse, and replaced with like-item only.
Vacuum tubes are warranted for 90 days against defects, except in cases of abuse, and replaced with like-item only.
Exceptions to our warranty policy are as follows:
Upscale Audio is not liable for any damage or injury caused by the improper use of its tubes or the use of an incorrect/incompatible tube type. If you are unsure of what tube or tubes your equipment uses, consult the manufacturer before making a purchase. Using an incompatible tube type may cause severe damage to your equipment and will void your tube's warranty.
Vacuum tubes are electronic parts and are not refundable under any circumstances.