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Andros Téssera



  • Description
  • Features
  • Specification
  • Reviews
  • Downloads
What is Téssera?
Téssera means 4 in Greek. This newest product from Zesto Audio is aptly named as it is designed to work with up to 4 different tonearms or turntables. Andros is a Greek island and the home of George’s grandmother’s family.
Design Philosophy

George Counnas, President and Design Engineer for Zesto Audio says, “There are so many great specialized phono cartridges available today, I wanted to design a phonostage that was easy to use, while providing the necessary inputs to accommodate multiple tonearms and be able to save the settings when you switch between channels.”

Building on the success of Zesto’s original Andros Phonostage, George wanted to take it further, not only sonically but with more features resulting in a quieter, fuller and more dynamic sound.

What’s the Most Requested New Feature?

True floating balanced outputs. These high quality transformer balanced outputs are driven by dedicated output tubes.

Circuit Topography

The Andros Téssera is built with a passion for Analog, designed with 100% tube circuitry and no solid state devices anywhere in the signal path, as well as all the switching is done with reed relays. This phonostage has a new circuit design that is partnered with significantly upgraded larger MC step-up transformers to capture the most delicate signals in the grooves.



  • Two completely independent dual mono channels, with LED indicators for A and B
  • Accommodates 4 tonearms, 1 MM and 1 MC per channel
  • All settings are saved when you switch between channels
  • Dual chassis with external power supply
  • 3 meter umbilical cable incorporating special RFI suppression to provide lower black levels
  • Dedicated high quality output transformers drivin by output tubes
  • True floating ground, transformer balanced XLR inputs and outputs
  • 12 position MC load per channel with more finessed adjustable options like 1000, 800, 700, 500, 400, 350, 300, 250, 200, 150, 100, 50 Ohms
  • Easily adjustable MC “Load on the fly” without klicks or pops so you can hear the change
  • 100% tube circuitry in the signal path without any solid state devices
  • All switching is done with relays
  • Ground lift switches are on each channel to prevent noisy ground loops
  • All the RCA and XLR connectors are Gold plated for better conductance and lower corrosion
  • All switches and knobs are easily accessible, nothing hidden inside to adjust
  • Recessed RCA connectors are durable and will hold up to the typical Audiophile who loves to change their configuration
  • Elegantly designed 16 gauge steel enclosure to help isolate the electronic “chatter” from nearby equipment
  • Each unit is hand built “Made in the USA”
  • 50 hour factory burn in on all circuits and vacuum tubes


Inputs per Channel

  • Two completely independent dual mono channels, A and B with LED indicator
  • Accommodates 4 tonearms, 2 per channel
  • Separate MM and MC inputs per channel
  • Each channel has independent controls and all selections are saved when you switch between channels
  • Selection switch for MC and 2 position MM 47K and MM 68K
  • MM impedance switch 47K or 68K Ohms
  • MM capacitance 220pf
  • MC transformer Balanced gold plated XLR input
  • MM and MC Single Ended RCA input, gold plated with isolated ground
  • 4 MC ground on/off switch
  • 12 position MC load impedance:1000, 800, 700, 500, 400, 350, 300, 250, 200, 150, 100, 50 Ohms
  • 4 Superior quality MC Internal step up transformers
  • 3 position MC gain switch for High, Medium & Low output cartridges
  • Two ground binding posts

Outputs per channel

  • High quality output transformers driven by dedicated 12AU7/ECC82 output tubes
  • True floating ground, transformer Balanced XLR gold plated outputs
  • Single Ended gold plated RCA output, with isolated ground
  • Impedance 150 Ohms
  • +8V max output level

Active Components

  • Four (4) Gold pin JJ ECC83S/12AX7 vacuum tubes with high quality gold pin ceramic sockets
  • Two (2) Gold pin JJ ECC82/12AU7 vacuum tubes with high quality gold pin ceramic sockets


  • Dual chassis
  • Power supply with 3 meter DC umbilical cable incorporating special RFI suppression
  • Locking bayonet connector rated for higher voltage and higher current
  • 3 internal linear regulated power supplies, 1 high voltage 250V and 2 low voltage 12V
  • Power supply dual color LED, yellow for standby and red for ON
  • Main unit push ON/OFF front power switch illuminates a red LED on Channel A or B
  • Power supply standby switch on the front
  • Power supply standby power rating 7 Watts
  • Power consumption 52 Watts
  • Standard 3 pin 15A IEC power connector on power supply
  • Voltage 110/120V AC 60Hz
  • Optional factory installed 220V or 230/240V AC 50/60Hz

Detailed Specifications

  • 3 position Gain switch
  • MC input 60dB, 65dB and 70dB or MM input 40dB, 45dB and 50dB
  • Noise – 90 dBu below max output level
  • Frequency response complies with the original RIAA curve within +or- 0.5 dB
  • RIAA curve is achieved using a passive filter
  • 1% metal film resisters throughout
  • Polypropylene capacitors throughout the audio path
  • All analog tube circuitry with no solid state devices in the signal path

Other Features

  • Controls on the front
  • “Made in the USA” using US and imported parts
  • Each unit is built by hand
  • 50 hour factory burn in on all circuits and vacuum tubes
  • Dimensions main chassis 17″ W X 14″ D X 5.5″ H, Power Supply 17”W x 8”D x 5”H
  • Weight: Main unit 25 lbs (11.34 Kg), Power supply 17 lbs (7.7 Kg)
  • Shipping weight 53 lbs (24 Kg), box 20″ X 20″ X 20″
  • 16 gauge zinc plated steel enclosure
  • Two year limited warranty
  • Six months warranty on Vacuum Tubes


Zesto Audio is proud to announce this prestigious award received by The Absolute Sound. The Andros Téssera is the premium phonostage in our line of three phonostages. We are pleased to have others hear the passion behind the Zesto Audio brand.

"...Sonically, it is full-bodied and serene. Everything stays in place, solidly rooted to its location, and is presented with beguiling warmth and naturalness of timbre and texture. The sound created by this phonostage maintains dynamic development, without favoring attack over steady-state tone or decay. Not only even-handed in its reproduction of musical notes, the Téssera also reproduces musical genres evenly, without favoring acoustic over electronic compositions, making it an easy choice for this year's TAS Phonostage of the Year award."

Thank you to the editors of the Absolute Sound for this amazing award!

The Absolute Sound Review of the Andros Téssera

"It was warm and full-bodied in a preferred way, but there was nothing thick or sluggish about it—the sound retained timing and pacing along with its portrayal of musical content."

Read the Full Article Here 
















Andros Téssera Review

by Robert H. Levi- Positive Feedback, Issue 89 - December 28, 2016

"I know of nothing more adjustable, more flexible, and more musically consistent overall than the Téssera." Click to read review


The 2016 Rocky Mountain Audio Fest reports are in and Zesto Audio is very happy indeed.


Jim Hannon's "Best of Show"

"Best Sound" (for the money)

"It put many more expensive systems to shame."

Jim Hannon - The Absolute Sound, RMAF Show Report - October 2016

Read full report

"Most Coveted Product" and "Auspicious Debuts: Analog"

Jim Hannon - The Absolute Sound - RMAF 2016 Show Report

"Zesto Audio's new Téssera Phonostage made me think I was listening to master-tapes.

One of the best sounds of the show!"

Read more..



RMAF 2016: Would This Stairway Lead to Heaven?

"This was one of those happy, expectation-fulfilling rooms where recordings actually sounded like music."

Jason Victor Serinus - Stereophile - October 2016

Click to read full report