Positive Feedback Logo

Zesto Audio Andros Allasso Step Up Transformer

12-14-2017 | By Robert H. Levi | Issue 94

Zesto Andros Allasso Step Up Transformer

The Zesto Audio Andros Allasso Step Up Transformer

Once upon a time, full-featured preamplifiers like the ARC SP-3 ruled the audio scene and contained a phono stage. Phono cartridges were high output MM or MI, and so the preamps of the day had only about 40 dBs of gain, max. Then along came the low output MC cartridge, and so was born the "Step-Up Transformer." Most of them sucked (noisy) or were quite limited in impedance choices. All were expensive for the period.

By the mid '80s, preamplifiers provided more phono gain, while records began to disappear from shelves. Finally, audio manufacturers stopped producing preamplifiers with support for turntables and went to linestages without any phono facilities whatsoever.

In the '90s, manufacturers began to produce stand-alone phono stages of very good quality. The Vendetta by John Curl is one of the most famous, and the E.A.R. 834P continues in production to this very day. Both handle MC and MM cartridges, but also offer few impedance choices. 

As MC cartridges surpassed the $1000 mark, it became obvious phono mavens required more exacting impedance choices to maximize better and more expensive MC designs. Though active stages offer certain advantages, they cost much more than phono step up transformers, and actually add more noise and distortion unless they are quite complex. It has become obvious that as MC designs approached the low .2 mV output level, an expensive active design would be needed to boost these expensive cartridges to yield truly great dynamic results. Active phono stages between $10,000 and $50,000 are not uncommon.

But the Zesto Audio Allasso is only $2995!

The Zesto Allasso is the brilliant and inventive George Counnas's creation, and performs exceptionally. He has designed and built complex audio gear that outperforms other products at double their price points. The Allasso is the least complex and expensive of them all, and is a truly stunning achievement in phono step-up devices. 

Specifications​ and features​

  • Frequency response: -3dB at 0.4Hz to 100 KHz
  • Phase deviation: 1° typical at 20Hz
  • Transformer noise: 2 dB @ 20 Ω, 1.8 dB @ 12 Ω
  • Hum rejection: 125 dB @ 60 Hz
  • Voltage gain: 12dB, 16dB, 18dB and 22dB
  • Step up ratios: 1:4, 1:6, 1:8, and 1:12
  • MC load: 40 positions in Mono, 40 positions in Stereo
  • Recommended output load: 47KΩ @ 200pF (MM input)
  • Inputs: Balanced and Single-Ended MC
  • Outputs: Single-Ended
  • Grounds: Independent input ground-lift switches
  • Grounds: Two ground binding posts
  • Mono: Takes one input and sends it to both outputs
  • Dimensions: 4"H x 6"W x 8"L (101.6mm x 152.4mm x 203.2mm)
  • Weight: 5 lb. (2.27Kg)
  • Shipping weight: 8 lb. (3.63Kg)
  • Box dimensions: 7"H x 9"W x 13"L (177.9mm x 228.6g x 330.2g)

When I compared the 1980 Ortofon T-30, perfectly restored and tweaked, to the Allasso using the Kiseki Purple Heart and the Grado Epoch, the Allasso was vastly superior. Goes to show you how even transformer devices have matured. Direct comparison to my E.A.R. MC4 which is similarly priced and outstanding, revealed comparable sonic advantages. 

The incredible thing is both transformers are equally without sonic signature. I was listening not to the transformers, but to the interconnecting cables, as you need two pair. Maybe, just maybe, the E.A.R. MC4 is a touch richer and the Allasso is a touch snappier. I can report minimal differences for what are the best step-ups I know of on our planet.

The Allasso has different remarkable advantages...it offers 40, not 4, choices to max out your favorite cartridge. It offers ground lift switches, mono, balanced facilities, and all front-mounted controls of top quality. It is built in California and serviced with minimal shipping. 

​I tried the Allasso with​ the Kiseki, Grado, Stein Adventurin cartridges, and more. Listened to .3 mV to 1mV output cartridges. Maximized cartridges at 100 ohms, 300 ohms, 500 ohms and more, with great results. Transformers are inherently simpler, quieter, and more real sounding in this application. I hear reel-to-reel dynamics and textures with the Allasso in the circuit. 

The Allasso allows fantastic flexibility and gives audiophiles a way to take any low output cartridge to a new level of performance. On a top system, a change of 30 ohms is audible and important. I had no idea. With settings of only 50 and 500 ohms available on one of my three reference phono stages, the addition of the Allasso is monumental. There’s much more granularity of settings available.

To my way of thinking, the Allasso is a must-own. Just place it ahead of any MM input on any phono stage and enjoy improvement only accomplished by fine tuning. With the new Grado Epoch Mono at 1mV output and with 300 ohms dialed in on the Allasso, I heard mono that was dynamic, ultra-detailed, and realistic. Depth was amazing. Noise and any inherent colorations were zero.

Take a look at the Gain, Ratio, and Loading Chart located here:


​This kind of versatility and performance is without equal.


The Zesto Andros Allasso Step-Up Transformer, now in production, is the world's most flexible Step-Up ever produced, at any price, by anyone. It is a top sonic performer with powerful dynamics and imperceptible sonic colorations or noise. The Allasso will maximize any low-output cartridge known, and is an ergonomic masterpiece. Its moderate price will appeal to many typical audiophiles, and the "perfection-seeking" analog aficionado, too. Its style and size are perfect and easy to place. The Allasso is incredibly shielded in steel plate to reduce RFI.

Congratulations to Zesto for once again designing a true beauty. The Zesto Andros Allasso Step-Up Transforme​r receives my very highest recommendation.

The review unit will not be returned!

Andros Allasso Step Up Transformer

Retail: $2995

US National Sales Manager

PJ Zornosa

[email protected]


International Sales and Marketing

Carolyn Counnas

[email protected]



George Counnas

[email protected]


Zesto Audio


3138 Calle Estepa Thousand Oaks, CA  91360  USA

Photographs courtesy of Zesto Audio