Output stages are almost always in connection with the dual action vacuum tubes EL34, 6L6 and for lower outputs EL84. The home Hi-Fi amps. so-called High-End class is not used only EL84 but also EL34, KT77, 300B - 2A3. The power tubes are significantly overloaded in comparison to professional products especially in class A.

     6 years ago we decided to test several involved of tube output stage according to the following criteria:

   After long experimentation the involvement ultralinear output stage in class AB with tubes 1xECC83, 2xEL84 the channel has been proved.

    The amplifier operates with automatic bias, what worked for exchanging tubes. Improper bias setting, for example about 3 V, could increase Ia to 50 mA because of such steep tube (up to 16 mA / V), what could cause damage of tube in a few minutes.

    The input unit (3 in) is controled by DO with switching through reed relays (RFT) and volume control with ALPS motorport (optional). The output transformer is a double C-core (S = 12.25 cm2), has 12 windings, 6 of witch are bifilar. This gives us the LSP < 2mH when Lp = 8H.

      Speakers with an impedance of 4 or 8 ohm (with a sensitivity of at least 89 to 91 db) in connection instance.:BYWIRE can be conetcted on the output. All these technical excellence are audiophile instrument with excellent sound expression.