The TAD 7189A is a 9 pin power pentode tube used mainly in amplifier in high-fidelity audio equipment. It requires a 9 pin Noval socket.
The 7189A is an improved version of 6BQ5 / EL84. It has identical characteristics regarding the typical application circuit of the EL 84, but is designed to withstand higher plate voltages and higher plate dissipation. The same applies to the screen grid. The screen grid is additionally connected with pin 6, the control grid additionally with pin 1 to achieve better heat dissipation.
WARNING ~ The 7189A power pentode is similar to the 7189 but has two pinout differences, as follows:
1. The 7189, EL84, and 6BQ5 tubes all reserve pin #1 for "Internal Connection" by the tube manufacturer. Pin #1 of a 7189A tube, however, always connects internally to pin #2 (the Control Grid). In a 6BQ5 or 7189 tube, pin #1 might or might not connect to the control grid - PLEASE CHECK THE AMPLIFIER WIRING AND ENSURE PIN 1 OF THE TUBE SOCKET IS UNUSED, IF PLANNING TO USE THE 7189A TO REPLACE THE 7189.
2. The 7189, EL84, and 6BQ5 tubes also reserve pin #6 for internal connection. But inside the 7189A tube, pin #6 always connects to pin #9, the screen grid. PLEASE CHECK THE AMPLIFIER WIRING AND ENSURE THAT THAT PIN 6 OF THE TUBE SOCKET IS UNUSED, IF PLANNING TO USE THE 7189A TO REPLACE THE 7189
If required, you can rewire the relevant tube sockets of an amplifier to accept any of the tubes under discussion. Just move any wires going to pin #1 over to pin #2. Then move any wires going to pin #6 over to pin #9. Do this on each of the applicable power tube sockets.
Note: The TAD 7189A is a NOS Soviet tube, fully tested and selected for TAD branding by Tube Amp Doctor.
Open Datasheet - TAD 7189A
