JM Labs Cobalt Monitors.

Cary AE-1 300B SET amplifier modified by Dennis Had with EAT 300B tubes, E.A.R. 834L Deluxe preamplifier, and a Dyna Stereo 70 modified by Sam Papadas with RAM KT88s.

ModWright Sony 999 CD/CACD/DVD player, Marantz ST6000 FM tuner, Marantz ST 17 FM tuner, and Parasound Broadcast Reference FM tuner. Denon 2200 DVD/SACD/DVDA Player

Kimber Hero, Harmonic Technology Pro Silway 3 and MagicLink 2 interconnects with Kimber Select Silver speaker cables. Harmonic Technology CyberLight interconnects between preamp and amp. Kimber Palladium AC, Harmonic Technology Magic and Fantasy AC, and Soundstring Pro AC cables used throughout system. Tara Decade power cord used on PS9.0 ModWright Power Supply to CD/SACD player. HT Battery Pack 4 for Cyberlights.


You are reading the older HTML site

Positive Feedback ISSUE 63
september/october 2012


zesto audio

Leto Preamplifier

as reviewed by Robert H. Levi


zesto leto

I enjoyed reviewing the Andros PH1 Phono Stage, with its strong musical performance and high value pricing for such a robust and fully featured tube piece. Now comes the Leto Preamplifier (Leto was the mother of Apollo in Greek Mythology), a non-polarity inverting preamp, which is supremely loaded with features and is a sonic tour de force, as well. The Letoís graceful styling, mirroring the Andros, makes it a thing of beauty; the fact that it is easy to get to tubes for the Leto and roll the sound make it a heckuva lot of fun!

The Leto is shockingly full-featured and masterfully designed. When is the last time you saw a high-end preamp with a balance control on the front panel and a mono button on the remote?! The Leto sports top-notch construction, and is made in America, too.

Enough gushing. On to the meat and potatoes!

The Test System

The Leto replaced my accustomed reference E.A.R. 912 Preamplifier in my primary review system.

Sources: E.A.R. Disc Master Turntable with two Helius Omega Tonearms, Grado Statement1 Cartridge, London Reference Cartridge, E.A.R. 324 Phono Stage, E.A.R. Acute III CD Player, ModWright Sony 9100 SACD/CD Player, and Day Sequerra FM Reference Tuner

Amplification: E.A.R. 890 mono-blocks

Speakers: Marten Bird Speakers with REL Stadium III Sub-woofer

Cables: Jorma Origo Interconnects and speaker cables, Kubala-Sosna Elation! Interconnects and power cords, Kimber 1036 Interconnects, and Harmonic Technology Magic 2 Power Cord

Special Accessories: Stein Music Speaker Matches, Stein Music Harmonizers, Stein Music E-Pads, and Bybee Golden Goddess Speaker Bullets

Most of the reviewing was done with the stock JJ supplied tubes, which performed superbly. I found the Harmonic Technology Magic 2 Power Cord a synergistic and exceptional combination with the Leto, and used it exclusively here. The preamp was fully broken in upon arrival, and George Counnas, President and chief designer of Zesto Audio [Zesto means HOT in Greek, by the way], set it up and tweaked it to perform at its best. It resided on the new and superb Townshend Seismic Sink, a model with no more air bladders, now available in quantity and at a lower cost.

zesto leto

The Sound

The High Band

You like super smooth, delicate highs, with pinpoint imaging? Then you will love the Leto. The high frequencies are both sophisticated and realistic, with an almost grainless presentation. The blacks are the blackest in its class, and this is a tube unit, too! This is an amazingly quiet design. Never edgy or unnecessarily crisp, cymbals, violins, flutes are all ultra-natural. Soprano vocals are superbly rendered. In my experience, overall high band definition cannot be bettered in this price range.

The Mid Band

I do not know of a preamp with this top level of high definition and sophistication that can match the Leto all the way out to $10,000... and the Leto costs way less than 10 kilobucks! The jump factor and overall dynamic power must be heard to be believed. The Leto produces an outstanding sound in my listening room, with well-focused imaging, excellent depth, superb soundstaging, and mountains of definition. It handles micro and macro details with equal skill. It has the speed of solid state and the smoothness of a great tube design, combined.

George Counnas, its designer, was a Decca Engineer for many years and an avid audiophile, and the Leto is the result of careful and thoughtful designing. For only the second product of a rather new company, I am stunned!

I most enjoyed the new Time Out Hybrid SACD from Acoustic Sounds with the Leto, the best digital disc ever of this great Brubeck album. The Leto brings it to life and puts it in the room. You just cannot ask for much more for $7500, in my opinion.

The Bass Band

The Leto has generous and detailed bass that is exciting and highly enjoyable. It is easily the equal of any solid state preamp in this price range, and better than any tube piece I can think of. You can feel the bass and appreciate the ultra-low distortion of the Leto. Play the Fanfare for the Common Man from the Reference Recordings Copland CD for explosive, exciting bass drum sound, and ultra-low distortion.

The low cello notes in the Dialoghi CD from Yarlung Artists are so very realistic and immediate. The bloom and warmth of the cello get extremely close to my much more expensive reference. Slam and speed are just outstanding. Decay and ambience are first rate.

Pushing the Envelope

Bulls eye!

I saved what I consider the Letoís magic bullet until now. The Leto has vanishingly low phase distortion. You hear virtually zero ambience that does not belong to an image. No deformation of the sound presentation; no mussy, no fussy. The effect is compelling for an audiophile, as acoustical images are now reinforced and in dramatic relief. Stray echo, ambience, and noise do a disappearing act worthy of Blackstone and Houdini. If this accomplishment were due to some kind of super tube, I would happily report it. It doesnít, though; it appears to be solely the result of great engineering the likes of which is pretty rare.

Heck, I have owned passive preamps which are noisier than the Leto. Any noise inherent in the recording being played sounds softer and more focused than many other designs I have auditioned. Noise is therefore easier to ignore.

The dynamic jump factor with this design is outstanding. I have heard many powerfully built solid state designs with less dynamic grunt. Love it.

The flexibility of the Leto is very nearly best in class. I think that the McIntosh C2200 has more bells and whistles, but the Leto has more unique features that are truly audiophile goodies you will love. Tube rolling with most tube gear these days is difficult and can be dangerous [like the Mac]. With the Leto, itís simpler (see my tips below). The ease of this important audiophile feature cannot be underestimated.

Mellifluous performance for me comes down to rightness of timbres, overall neutrality with low coloration, and excellence in production of high definition. This describes the Leto quite well. Complement this with the supremely low phase distortion discussed earlier and you have a winning product in my book. Though not an engineer, I suggest that the Leto is a groundbreaking design. How else could it achieve so much and not cost five figures??

Tweaking the Leto

If your system is on the warm and rich side of neutral, you will probably find the stock Leto a paragon of perfection from the get go. If your system is already very neutral and highly revealing, and you desire a bit of extra warmth and sweetness along with all the definition the Leto may be capable of, no problem. Replacing the two 12AX7 JJ tubes with Mullards [available, for example, from Kevin Deal at Upscale Audio in Upland, CA] will give you a boost in warmth and sophistication. Replacing the 12AU7s went too far in my system, so I would not change them. Tube rolling is the sport of audiophile kings, and the Leto is the perfect platform for subtle and fun tube juggling.

I found that the Leto is sensitive to power cords, so a change to a richer, full-sounding cord may be helpful, or vice versa if you listen to lots of rock. Most high end gear responds to this kind of tweaking, so do not be surprised that cables can make such a noticeable change in your sound. The difference is that the Leto is 95% spot-on right out of the box, so you will be seeking only a subtle change to perfect your system's performance. Just start with your favorite audiophile power cord and have at it. As I said, my favorite with the Leto was the Harmonic Technology Magic 2 Power Cord.


I am amazed by the flexibility of the Leto. The remote features effective and useful functions, and you can aim it behind you, away from the system, and it will not fail to work the preamp. Love it! The shielded, individually-grounded, and countersunk RCA and balanced inputs and outputs are gorgeous. This is a very quiet design, and a leader in its class in my experience. It even has a switch to float the grounds in each channel! The Leto is transformer-coupled, mostly point-to-point wired, and steel-shielded like crazy (it weighs in at a beefy 23 pounds). Though not low-cost, for sure, it is worth its price by every measure I can conjure up.

The Leto is laden with features, so I recommend you go to and read about the long, long list of capabilities you get for your hard earned audio dough. Lots of unique stuff here, including special audio loops that work with the preamp off! Plus, I never heard a pop or a snap from any switch or button or knob at any time during the evaluation.

That says a lot.


New from Zesto Audio comes the tubed Leto Preamp, pushing the envelope in value and performance in its price range and beyond. With styling similar to the Andros Phono stage, the Leto is a powerful sounding, highly detailed, fantastically quiet, and superbly musical masterpiece that will complement the finest systems. Designed by a brilliant and pragmatic designer who knows great sound and ergonomics, the Leto performed like a thoroughbred in every way musical, and was a joy to control and adjust. The fun factor while working with the Leto made me rethink what has been missing in minimalist preamps that cost even more money these days. What a jewel! The Zesto Audio Leto is a killer design to my way of listening and loving recordings, and may just be the preamp you will buy and keep for the very, very long haul.

The Leto receives my highest recommendation. Robert H. Levi

Leto Preamplifier
Retail: $7500

Zesto Audio