-RARE TUBES PERFECTLY MATCHED -Metrix U61b Tested (Nominal HT : 250v , G2 : 225v G1 : - 14 @ 100mA) Tube 1 : 98mATube 2 : 98mATube 3 : 98mATube 4 : BROKEN FOR DISPLAY -Come in white box ***OFFER ACCEPTED***

Ei KT90 Vacuum Tube. Has tested good written on its box. I am unable to test so sold as seen. For exact international shipping rates please contact me.

For sale NOS NIB Ei Yugoslavia KT90 tubes. Made in Ei Yugoslavia factory! OO getter, welded plates with copper rods inside plate! Very rare to find. Tested NOS and STRONG on RoeTest V10 (the best modern professional tube tester!) -- see images for detailed measurements PRICE IS FOR ONE QUAD (FOUR TUBES).I will pack and secure tubes good. Feel free to contact me.

These Type II Ei KT99A power tubes are specially selected Ei KT90 tubes made in the early 1990s in the former Yugoslavia. They are labeled for Gold Aero and the gold print on the glass reads: KT99A Specially Selected for Sonic Frontiers. Type II KT90 tubes have visible spot welds where extra reinforcement was added to the plate structure to allow for greater dissipation than the earlier Type I KT90 tubes. Type II KT90s can be used as substitutes for 6550 / KT88 power tubes in most applications. These tubes have been screened for shorts and excessive leakage, gas, and noise / microphonics. They have been burned in, tested at typical operating voltages on a laboratory grade Amplitrex AT1000, and matched for both current draw (50.4 & 55.4 mA) and transconductance (109% & 112% Gm). They ship in new white boxes with test results.

These Type II Ei KT90 power tubes have welded gray plates and dual O getters. They were made by Ei in the early 1990s in the former Yugoslavia. They are labeled for VTL and say Yugoslavia with the Ei logo (partial). The Type II KT90 tubes have visible spot welds where extra reinforcement was added to the plate structure to allow for greater dissipation than the earlier Type I KT90 tubes. Type II KT90s can be used as substitutes for 6550 / KT88 power tubes in most applications. These tubes have been screened for shorts and excessive leakage, gas, and noise / microphonics. They have been burned in, tested at typical operating voltages on a laboratory grade Amplitrex AT1000, and matched for both current draw (58.0 & 60.0 mA) and transconductance (115% & 118% Gm). They ship in new white boxes with test results.