A phono preamp is, in general, inherently simple in terms of its user interface, nevertheless Zesto has done a good job trying to make something that looks and feels special. Chassis design takes advantage of the contrast between three different finishes, black, aluminum and a highly reflective surface behind the tubes. Add some curves and there you have it: Andros is indeed something worth to display instead of hide it somewhere in a rack. The front panel contains no switches (the on/off is cleverly positioned on the left side) and there is no need for a protection cage around the tubes, since the heat they produce is not excessive. Surely enough, the interesting part of the preamp lies in the back panel.

There, the user will find two sets of inputs, one for MM and one for MC (single ended for both but with a balanced input for MC too), a single ended output and a series of simple switches through which he can choose the input, the sensitivity for MC (high/low) and to float the signal ground if necessary. There's also a load selector for moving coil cartridges with eight positions that offers a reasonable range of options from 20 Ohms to 1kOhm. The connectors are of good quality and, overall, the chassis looks heavy and well-attended.

Inside Andros there is proof that Counnas opted for a rational, simple but not simplistic design that systematically seems to avoid pitfalls. A result, probably, of the experience of a man who has designed other things besides audio. Let me explain: Andros uses step up transformers (from Jensen) as the first stage in the MC input, a good approach for low noise that, also, offers the option for a balanced input without the cost of additional active circuitry. Input load selectors are high quality components from Grayhill and the whole signal rooting is hard wired close to the transformers and the input connectors. Finally, Andros uses standard regulated power supply modules from International Power, a company that specializes in this field. Both the low and high-voltage power supplies (12V/250V) are based on a classic regulation circuit (with an LM723) and a power transistor for handling the current (a 2N3055 for low voltage and a MJ423 for the high voltage).

The main circuit includes two stages with two dual triodes each, all ECC83 S with gold plated pins from JJ Electronic, with the de-emphasis network between them. It appears that Andros uses the passive approach for all time constants. Components used here are of low tolerance, (Dale 1% resistors and polypropylene capacitors), with Zesto to claim an inverse RIAA curve accuracy of + /-0.5dB. Chassis support points are of high compliance material in an attempt to isolate the tubes and the rest of the circuit from external vibration sources.

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