Brand New Electro-Harmonix KT88 Matched Quad, Burned In (4 tubes). High power kinkless-tetrode for use in amplifiers such as the Marshall Major. This tube is a favorite of audiophiles.Can be used in place of 6550 for a more'round' bass signature. We burn in our power tubes for an extra 24 hours before matching them, giving them a total of 48 hours of burn in time (this is because they are burned in for 24 hours at the factory). The extra burn in stabilizes the plate current, meaning these tubes will not "drift" out of bias. Doing this extra burn in also allows us to weed out the weak and defective tubes by putting them through this 24 hour stress test.
This will ensure you will have working tubes for a long time. At Tonal Tubes we match tubes using a tester that enables us to match tubes at high plate voltages as well as various bias voltages.
This means that when you install these tubes, they will be a tight match inside your amplifier. We have very strict standards when it comes to matching. We match power tubes within 5% for plate current and 10% for transconductance.Most other retailers will match to just one of these values, however it is important to have both of these values matched. This is not a simple process and does take lots of time and dedication since tubes can vary so much from the factory. Having matched power tubes is important because it reduces hum from your amplifier. It also allows you to get more life out of your tubes, since each tube will be working approximately the same amount. Both the plate current and transconductance will be written on each and every tube box. See the fourth picture for an example of what we mean. Why You Should Do Business With Us. Every single tube is checked for shorts and leakage on a calibrated Eico 667 tube tester. Comes with original packaging straight from the factory, as shown in the picture. We are musicians who crave awesome tones. We all know that swapping out tubes can be one of the more effective ways of improving your tone. At Tonal Tubes, we help you achieve that next level tone. The item "New 4x Electro Harmonix KT88 Matched Quad / Quartet Four Tubes Burned In" is in sale since Wednesday, October 26, 2016. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets". The seller is "tonaltubescom" and is located in Durham, North Carolina. This item can be shipped worldwide.