Mastersound 845 Compact integrated amplifier

Back in the 1950s, Cesare Sanavio, then a new electronics graduate with a specialty in output transformers for tube amplifiers, began his career in radio and television, traveling to various locations outside his native Italy to apply his expertise. Eventually he settled in Paraguay and started designing tubed sound systems for public installations, teaching his son Luciano the art. A few years later, Sanavio and his family returned to Italy. There, he worked as a consultant to several hi-fi companies. Finally, in 1994, drawing on decades of accumulated knowledge of tube-amplifier design and manufacturing, and a particular focus on output transformers of the highest quality, Cesare Sanavio and his two sons, Luciano and Lorenzo, formed Mastersound.

When Cesare Sanavio died, Lorenzo and Luciano continued operations. In 2015, the company re-formed, with some new international business connections and a new CEO, Antonio Ferro. The company's new headquarters is in Arcugnano, a small town in the province of Vicenza. It employs six people, four in production and two in the office. Luciano is now the company's lead designer and production manager, a role previously held by Lorenzo, who has retired from such duties but remains a co-owner of the business.

Today, Mastersound's stated goal is to produce tube amplifiers of the highest quality available on the market. To this end, the company hand-builds each amplifier in its own laboratory, "one by one, with extreme care," their "Made in Italy" webpage asserts, "using the best components" and manufacturing techniques. Mastersound output transformers are hand-wound on a mechanical winding machine in a secret, closely guarded process the company claims makes them "unique in the world."

The company's line currently includes three preamplifiers, which use ECC82 and ECC83 tubes; three monoblock power amplifiers utilizing 6SN7, 300B, and 845 tubes; and nine integrated amplifiers, which, variously, set ECC802, EL34, 300B, 6SN7, 845, KT120, and KT150 tubes aglow. The Compact 845 integrated ($10,495), the subject of this review, is one of Luciano's designs.

Design
The Compact 845 is beautiful. Its stout pair of Psvane 845B HiFi Series power triodes is protected by a butterfly-like, laser-cut, anodized aluminum tube guard; its curved black-walnut side panels adorn a hefty, CNC-fabricated chassis made of antimagnetic stainless steel. The 75lb Compact 845 stands 10.8" high, 18.1" wide, and 16.3" deep, which stretches the "Compact" designation to its limit.

The sleek tube guard creates a symmetry that ties the amplifier's external components together in graceful, flowing lines. The Compact 845 is sure to draw looks and praise for its striking design.

Viewed from the front, two large aluminum knobs occupy the two sides of the faceplate: The left knob allows the user to choose among five input sources, marked CD, Tape, Tuner, Aux, and Direct; the right knob controls a motorized, Alps 50k ohm logarithmic potentiometer, one of the silkiest, most solid-feeling volume controls I've encountered—a feature I appreciated especially after learning that the lovely, wood-encased remote control didn't work.

Back-panel connections include the two pairs of RCA and XLR inputs for connection to an external preamplifier; three pairs of gold-plated RCA inputs and one pair of XLR inputs; two sets of speaker binding posts (4 and 8 ohm taps); a fuse plug, and an IEC power connector. The XLR and RCA jacks are manufactured in Italy, by Axiomedia, as are the speaker posts. The unit sits on four robust, tall feet.

As mentioned, the output transformers are the company's particular focus and point of pride. In a recent email, Ferro, the CEO, elaborated. "Power and output transformer are designed and built by hand, by us, using high-quality OFC copper cable and grain-oriented sheet metal. Our transformers have EI-type cores. Each amplifier has its own dedicated power and output transformer, designed especially to obtain the maximum performance from the tubes used. Our output transformers have a unique design that permits a very large bandwidth and allows us to zero the feedback, with enormous benefit to the naturalness of the sound."

The Compact 845 includes custom capacitors by Italian firm ICEL. Why custom? They're "made for us in polypropylene," Ferro wrote, "because this type allows much better insulation." The amplifier also makes use of Vishay 1% resistors and Swiss Huber+Suhner wire. In addition to the big Psvane 845B HiFi tubes, the Compact 845 employs long-plate JJ ECC802 triodes in the preamplifier stage (because they're "quieter and less microphonic than the standard ECC82," Ferro explained) and TungSol 6SN7GTBs driver tubes. The 845 uses solid state rectification.

Tube bias is factory-set and mustn't be altered, Ferro stressed, except when changing tubes. "Biasing ... is usually unnecessary for the 845 because these tubes usually work for a very long time. We have our own design of auto-bias circuit that maintains the tubes' value constant during [their] life. Our triode amps are set at the factory and only need be set again when the power tubes [are] changed." Tubes should, consequently, only be changed by a qualified technician. "For our pentode amps, it's completely automatic and doesn't need to be set again until the tubes need to be changed."

Ferro recounted when Luciano Sanavio illustrated the difference between class-A and class-A/B designs by way of analogy: "Luciano did a demonstration at an Italian audio dealer where he asked, 'Do you know the ball-throwing machine that is used in tennis for training? You can have the ball inside the machine that is already turned on, or you can insert the ball and then turn on the machine: class-A is the first case—at all times you're running at maximum power; class-A/B, instead, operates only when necessary. Therefore, class-A/B won't have the same reactivity and speed in transients as class-A.'" The Compact 845 operates in class-A.

Setup
The Compact 845 fit snugly into my five-tier Salamander Archetype rack. I connected it to my Tavish Design Adagio phono stage and, variously, pairs of DeVore Fidelity O/96, Volti Audio Razz, and MoFi Electronics SourcePoint 10 loudspeakers with Analysis Plus Silver Apex speaker cables. Acoustic Signature Maximum Neo, Thorens TD 124, and Kuzma Stabi R turntables were my analog sources.

When you turn on the Mastersound amplifier, a red LED begins to flash; when the amplifier reaches operational status, it stops flashing. For optimal performance, the Compact 845 should be turned on at least 30 minutes prior to listening, the manual advises, to allow the tubes to stabilize at their optimal operating temperature. The manual also notes that during operation, the cylindrical transformer enclosures, which act as heatsinks, become quite warm, which is normal.

The manual recommends a minimum of 200 burn-in hours for peak performance. I dutifully streamed Roon/Tidal/Qobuz for about this duration, using an Apple iPad mini and a HoloAudio May DAC as a source.

COMPANY INFO
Mastersound SRL
Via Galileo Galilei 2/2 – 36057
Arcugnano VI
Italy
info@mastersoundsas.it
39-392-997-6159
ARTICLE CONTENTS

COMMENTS
ChrisS's picture

...no longer "here"!

https://www.stereophile.com/%20content/devore-fidelity-orangutan-o96-loudspeaker-jim-austin-september-2017

John Atkinson's picture
Sorry about that. There was a wayward space character in the URL. Fixed now and the follow-up can also be found here.

John Atkinson
Technical Editor, Stereophile

DavidMA's picture

I enjoyed this review. But I'm always curious about how the review aligns to the measurements.

I've read through the final two paragraphs of the Measurements section of some of the more recent tube amps/integrated amps. Whereas the measurements for solid state amps often will conclude that this piece of equipment is "well engineered", the Measurements section for tube amps often has a statement along the lines of, "...the amp performs along the lines of what one would expect for a tube amp with zero negative feedback..."

The commentary always seems to imply that there are negative sonic consequences to these amplifier designs that are not commented upon by the reviewer of the equipment that a buyer should be wary of. It is as if Stereophile has two minds about tube designs. I did not find any reviews of tube electronics without this dichotomy.

I'll admit that I do not understand the testing section - I don't have a background to understand the tests and the interpretation of the graphs - If Stereophile has a lay-person's guide to the Measurements section and could make it available on-line, that would be helpful!. But I do read the last couple of paragraphs summarizing the Measurements as I am curious to see how the measurements align to the review. I find it interesting.

I have two amps - one solid state, and one tube. I enjoy them both.

John Atkinson's picture
DavidMA wrote:
The commentary always seems to imply that there are negative sonic consequences to these amplifier designs that are not commented upon by the reviewer of the equipment that a buyer should be wary of.

That is correct. When I write "The amp performs along the lines of what one would expect for a tube amp with zero negative feedback," the measured performance predicts departures from a neutral sonic character that will be audible.

For example, the interaction between the amplifier's high output impedance and the loudspeaker's impedance modifies the speaker's frequency response. The high level of second harmonic distortion will add "warmth" to the amplifier's sonic signature.

This behavior, of course, may well be perceived as positive by a listener, particularly if it compensates for something elsewhere in the system. But it still needs to be pointed out in a review.

John Atkinson
Technical Editor, Stereophile

Jim Austin's picture

I just want to make it clear that the opinion expressed by JA1 here, though very well-supported, is not universally shared.

It's true--no one connected with reality can deny it--that certain features in old-school tube amps cause departures from neutrality, especially with loudspeakers with impedance curves that drop below, let us say, 4 ohms, which is most modern loudspeakers. No one can deny it because they are measurable at clearly audible levels. But there's another school of thought--embraced by certain other Stereophile writers--that believes that something less tangible is retained in some such amplifiers that is lost in demonstrably more accurate ones. Such opinions are based on subjective experience--self-perceived connection with the music. This makes them literally irrefutable--they cannot be tested objectively, so they cannot be contradicted, which is annoying--yet (and this is my opinion, as the magazine's editor), in a magazine committed to subjective experience--to listening--above all else, such opinions must not be dismissed out of hand.

Edit: I thought I should add that the opinions/beliefs I'm referring to are held by many of the most experienced, devoted, passionate audiophiles. I do not take that lightly.

Jim Austin, Editor
Stereophile

Lars Bo's picture

Thanks, Jim.

I agree: While "picky" and no surefire thing, good SET amps can be musically magical.

To quote Art Dudley (who felt SET could be something very special indeed (obviously, despite some drawbacks)):

"The fact is, there's an archetypal high-end audio sound and an archetypal SET sound. At its best, high-end audio sound is impressively open and clear, with deep bass, shimmering highs, and a flair for thrilling spatial effects; at its worst, it's lifeless, boring, constricted, undramatic, uninvolving, and incapable of any suggestion of flow in the music.

At its best, SET sound has the kind of punch and drama that can startle you out of your pants—plus real musical drive, momentum, presence, and tone; at its worst, it has no bass, no treble, and a level of coloration and sheer fuzz that could drive you out of the house after just a few songs." *

And:

"(Single-ended typically convey) An almost scary sense of presence on voices and solo instruments. Superb immediacy in terms of musical nuance. Equally superb drama, with the greatest dynamic contrasts available in home playback when mated to the right speakers. At least good to very good performance in terms of getting the notes and the beats right. A sense of flow and momentum in musical lines that is second to none. And an uncannily natural way with textures and colors—that beguilingly beautiful, gooshy feel that makes it easy to forget you're listening to electricity imitate people playing music." **

*https://www.stereophile.com/artdudleylistening/1107listen/index.html
**https://www.stereophile.com/content/listening-25-page-2

Jim Austin's picture

Are you Lars Bo the musician? I suspect that this is a fairly common Danish name.

I've noticed an interesting phenomenon: These comment threads are carefully monitored by denizens of a certain hi-fi discussion site. Whenever I write anything here, especially if it seems to contradict one of our reviewers, my comment is copied and posted on that other website and potshots are taken. Many of the posts are ignorant and poorly informed. Almost all are ungenerous. A few are intelligent enough but lack wisdom. I thought I'd write a little bit more and see if the new information provided here is conveyed.

I have no tubes in my main system. When I wrote what I wrote above, in my reply to JA1, I was not describing myself but others whose views I respect. I'm not a tube guy. My main reason is that tubes are unreliable, which undermines my confidence in my system: Do I have a tube going bad, or is it something I ate?

There are many passionate audiophiles--again, not me--who have been on a lifelong journey seeking the best sound--the most musically expressive, humanly communicative sound. They are like artists, or, at a minimum, seriously engaged art lovers, people for whom music is daily sustenance. They relate to their music (and musicians), via their hi-fi systems, in a deeply human way. A lifetime of listening has made them astute observers, far beyond what most of us, who dabble in a hobby and limit our thinking to DBTs, will ever achieve.

When they say there's something going on beyond second-order distortion and output-impedance-induced deviations from neutrality, I take that seriously. To repeat: This is worthy of respect.

In serious pursuit of a musical connection, some may choose to limit themselves to verifiable fact--to approach the reproduction of recorded music as if it were an intellectual exercise. Others treat it as an art form--one they are deeply committed to. In pursuit of connection to music, each approach has merit.

Jim Austin, Editor
Stereophile

Lars Bo's picture

Hi Jim,

Yes, Lars Bo is not an uncommon name in Denmark (either as a given or full name). I do play various instruments, though only for my pleasure for many years. But I spend way more time listening to and engaging in playback music (mostly as an art form you describe so well).

I agree with you: I have many friends whose approach and gratification in hi-fi are somewhat different than my own. Once in a while, some may even not like Bourgogne... We can discuss our "paradigms" and preferences passionately, but genuine interest in and respect for each other's perspectives make all the difference.

georgehifi's picture

JA what's with the Mars attack test sweep tones automatically played in the background when the measurements page on this amp is first opened up?? Or is it the new audible intro to say we're now in measurement mode?

Cheers George

John Atkinson's picture
georgehifi wrote:
JA what's with the Mars attack test sweep tones automatically played in the background when the measurements page on this amp is first opened up??

What browser are you using? The audio file - the recording I made of the low-level sound the Mastersound amplifier made when I measured its frequency response - should only play when you click on the "Play" button.

John Atkinson
Technical Editor, Stereophile

teched58's picture

Yes, JA1, the Mars Attack of whistling not dixie autoplays for me, too. I'm using Chrome on Win10.

JRT's picture

...on Chrome browser on Android.

Charles E Flynn's picture

Safari 16.4.1: File does not appear on the Measurements page at all (!)

Brave Version 1.51.110 Chromium: 113.0.5672.77 (Official Build) (arm64): File autoplays and its controls do not display properly.

Firefox 113.0 (64-bit): File played only when Play button was clicked.

John Atkinson's picture
Charles E Flynn wrote:
Safari 16.4.1: File does not appear on the Measurements page at all (!)

Brave Version 1.51.110 Chromium: 113.0.5672.77 (Official Build) (arm64): File autoplays and its controls do not display properly.

Firefox 113.0 (64-bit): File played only when Play button was clicked.

Thanks. Webmaster Jon Iverson fixed my buggy code. The file now plays correctly in Safari as well as Firefox. Don't have Chrome or Microsoft Edge installed, however.

John Atkinson
Technical Editor, Stereophile

Charles E Flynn's picture

You are welcome, and thanks for letting us know that the code has been fixed.

georgehifi's picture

It's kinda good, like having Sheldon Cooper intro you into the believable section of Stereophile.
To have this when you open up measurements page, reminds you that your now leaving the subjective and entering the objective part of the review.
BTW mines Chrome also on Win 10.
Cheers George

georgehifi's picture

I liked it, an audible que that you were now entering into the realm of reality/truth, without any subjective fairy tales to sway you.
I say bring it back JA!

Cheers George

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