Ruby Tubes

Tube Talk

New 12AX7
The new RUBY 12AX7AC7 is the latest tube developed at our Factory. It is the quietest of all our 12AX7 type tubes, both in terms of microphonics and mechanical noise.

To eliminate the mechanical rattles, we started with new, tighter tolerance micas, redesigned the plate structure and added new assembly controls to make the RUBY 12AX7AC7 free of mechanical rattles caused by the vibrations inherent in a high gain combo amp. The famous sweet tone on the Chinese 12AX7 tubes was preserved. In the process, we also got a significant reduction in the microphonics of the tube. The new tube has the same high gain as our popular 12AX7AC5 tube.

EL34BHT
We have had a great response to our new RUBY EL34BHT tube. Many engineers have asked about what kind of power can be expected from the EL34BHT. In our tests, we used 600 V on the plates, 540 V on G2 and a bias setting of –54V. The tubes idled at 25ma each. The power output from a pair of EL34BHT tubes using these voltages was 70 watts at clipping.