The American firm Zesto Audio has presented an updated Andros Téssera tube phono stage with a dual mono architecture.
The circuit now lacks a pull-up resistor, and the signal is taken directly from the secondary winding of the step-up transformer. This is said to have increased the dynamic range from 108 dBV to 116 dBV.
The input is now equipped with 12DW7 dual triodes with better signal-to-noise ratio. For the updated circuit to work, a new external power supply was needed. The peculiarity is that the voltage across the lamps has been increased from 250 to 300 V, and the power consumption has increased from 52 to 60 W. The maximum output signal has risen from 8 to 12 V.
According to the developers, Andros Téssera will allow you to accurately select the load for the MC cartridges. There is a 12-position switch on the front panel that changes the resistance in the range from 50 Ohm to 1 kOhm.
Four cartridges can be connected to the updated Andros Téssora: one MM cartridge (via RCA) and one MC cartridge (via RCA or balanced XLR) to each of the two independent inputs labeled A and B. And when you switch between them, all settings will be saved.
The novelty is completely manufactured in the USA. The cost of the Zesto Audio Andros Téssera phono stage in the US was $18,000.