'm looking at it, watching it, looking again, tapping it, unscrewing it and then re-assembling it again, and I still can not comprehend this, how is it possible that such a product, with such class, with such build, and with such looks, and produced in its entirety within an EU country, … how is it at all possible that it costs only 4000 PLN. When I read about the genesis of the creation of the Silver Luna, the matter has clarified somewhat, although not quite completely. It's still too big a "bang" for too small a "buck".

If I were to bet on some form of explanation of the matter, I would claim that it is the transformers that are being used in it and that we get them "at cost", whilst other manufacturers would need to pay at least two times as much for them, if not more. This is possible because the owner of the Fezz Audio brand happens to be the company Toroidy.pl, a known entity both in Poland and abroad, one which happens to be a manufacturer of toroidal transformers. Is a family business that is managed by Mr. Lech Lachowski and his two sons, Thomas and Maciej.

I am sure that you remember this entity from the descriptions of some of their designs and from the photos from "High Fidelity". Their transformers are used by various companies, including brands like Ancient Audio from Cracow, or Mytek - an American company, but manufacturing it's DAC converters in Warsaw. Taking the essential costs outside of the parentheses, and then cutting them down a bit is indeed a big relief for your wallet. The fact being, that within the final price of a ready made vacuum tube amplifier, the most significant components are: the chassis, the tubes and the transformers. And out of the latter, as a rule, almost always come at least as a triplet: one power supply transformer and two speaker output transformers. More often than not, you also have an inductor, a choke. These are the essential elements that “define” the sound of the amplifier.

The output transformers

All is fine, though attention is drawn to the association between the name "Toroidy.pl" and the type of amplifier, specifically being a tube amplifier. The truth being that the vast majority of such devices use output transformers, just before the speakers, and such transformers are of the traditional, E-I lamel based type. This historical legacy stems from the 20-ies and the 30-ies of the XX-th century, from a time when other types of transformers were simply not available. As for the power supply, this is a wholly different story, as the present day designers have no qualms in adapting newer solutions, and for quite some time they are now using both the E-I based transformers, as well as toroidal ones, or the "double C" core, or the R-core units.

The resistance, hesitance against using toroidal output speaker coupling transformers relates to both the sound characteristics, by which they differ from the E-I types, but it has also to do with “tradition". On top of that comes yet another aspect, one about which designers are very reluctant to speak of, being the fact that the proper design of a toroidal transformer for a tube amplifier, especially if it is of the Single-Ended type of architecture, is a very difficult task. Difficult to design, difficult to produce and it costs quite a lot. Therefore, designers do not have too many experience with them. And it is so much easier to simply go with the flow, choose an EI based transformer and have peace of mind. Be done with it. I'm not saying here that such an approach is wrong, that sticking to “E-I” is a mistake, because it is not. I'm just saying that the total abandonment of toroidal transformers, solely for practical reasons, impoverishes our industry. The more so should we respect the companies that have taken up this challenge, together with Amplifon at the forefront. Silver Luna

Silver Luna

As stated by Mr. Maciej Lachowski from Toroidy.pl, the Silver Luna amplifier was created so as to prove that toroidal transformers are in themselves are not at all that bad. To the contrary, they offer tangible benefits, amongst which the most important one is a much wider upper bandwidth capability. It is good to know that the so called "Tube sound", especially in the context of vintage amplifiers, is often a result of the operation of output transformers which cut off the bandwidth, frequently limiting it already at 10 kHz! You can work around this, but such solutions generate additional costs. And please look at the frequency response of this here amplifier under test: with 77 kHz from the top side, it is more than is being delivered by quite a broad group of transistor based amplifiers.

For starters, however, we get our first view, our first impression of the solid of the device. The solid has immediately caught my eye, during the Audio Video Show 2015 exhibition, and immediately after that, the price. The combination of the two bothered me, so I asked for a unit to conduct a test. At home, when I put this ‘Finite Elemente’, amplifier on the shelf, it looked even better. A low profile, a robust, precisely manufactured chassis and polished shields for the transformers – this is something I would expect from an audio device, but something that I do not always get. The chassis may be painted to any one of four color schemes, and with an additional surcharge, to any other color. For the purposes of the test, I chose a fantastic-looking version of red.

The device is built around the EL34 tubes, power pentodes invented in 1954 by Mullard, and by Philips, being its owner. This design is a push-pull, working in class AB1, so there is a pair of two identical power tubes in each channel. The choice of class of operation was dictated by the intention to obtain an output power that is higher than the one possible within Class A. The voltage amplification and phase reversal is dealt with by the ECC83 tubes. All of these vacuum tubes have been specially designed for application in audio systems and can be spotted both in home appliances, as well as in on-stage equipment, or electric guitar amplifiers. The output transformers are toroids of the manufacturers own construction and production, but the architecture is classical, being an ultra-linear topology. The output power is 2 x 35 W. Three line inputs are available. Remote control is not.

The circuitry was designed by Eng. Zdzisław Kulikowski - a man with multiple years of experience in the design of vacuum tube circuits, who cooperates with Toroidy.pl since many years. The design of the chassis and the finishing touches were a joint work effort of the whole team. The chassis turned out very well. The amplifier resembles, in a very unusual way, the structures similar to those that we may meet in Japan - in terms of both sensitivity to shape and color, as well as to overall sturdiness.

Upgrading

Tube amplifiers are fantastic objects for various upgrading efforts. The unit typically bought in a sales outlet is similar to a series production-line automobile, one which you can later change into a racing car, whereby that what remains remnant of the original automobile is but only the upper chassis. But in the case of the Silver Luna amplifier, I would not be too hasty in applying such changes. Indeed, this is a complete, fleshed out, coherent device, competently designed, one in which everything is well balanced. The sound of this unit, as it will turn out, is so good that there is no need to fiddle around in it – for quite some extended period of time.

The nature of an Audiophile is such that sooner or later it will nonetheless start to take precedence and overwhelm his common sense. Knowing this a-priori, I would like to draw your attention to a few things that “could” be changed. First of all - the legs. In place of the current ones, you could either screw on the feet sourced from Franz Audio Accessories, or Pro from Audio Bono. Or, you could do just as I did, during the test - I put the amplifier on Pathe Wings PW-AVSH cones, which are made of a plywood called "Panzerwood". They are fantastically manufactured and have the good looks. Under the amplifier, you then need to stick on some rubber grommets, so that the cones are stable.

The second change is also a non-invasive one, being a replacement of the mains fuse. It's easy, because the fuse housing is accessible from the outside, integrated with the mains socket. I suggest that you try out the Verictum X Fuse. And finally – the vacuum tubes. Here the possibilities of fiddling around are enormous. Old, unused tubes (i.e. NOS), such as EL34 sourced from Mullard, Philips or others, and/or the ECC83 – from Tesla, Neumann or Siemens, are a good route to pursue.


Further upgrade steps shall require changing elements inside of the amplifier, thereby invalidating it’s guarantee. This would relate to applying new coupling capacitors, applying higher capacitance values within the power supply, or exchanging the internal interconnects with some other ones. These would also be the most expensive upgrades, and their price would exceed the price of the amplifier itself, so there is nothing to run for.

MACIEJ LACHOWSKI
The owner and constructor

Our family business, the Toroidy.pl company, is a basis for the Fezz Audio project. Since multiple years, we are firmly entrenched within the world of audio. We supply mains transformers for a range of renown companies. For over 20 years of business activity, we have completed a lot of interesting and prestigious projects. We have partnered up with companies such as: Mytek (Manhattan DAC), LampizatOr, Amare Musica, Audio Valve, Ancient Audio Wile http://wile.com.pl < / a>, or Baltlab, receiving from them positive feedback.

A few years ago, we decided to create something that would break the stereotype. It was to be a toroidal speaker transformer, to be used for the construction of single-ended amplifier architectures. We have succeeded. Our design work on this construct took three years, in which we have developed a unique technology for the production of transformer cores and windings. As a result, we are now able to design, and most importantly to produce, speaker output transformers for virtually any type of vacuum tube, be it used either in an SE, or in a Push-Pull topology. The technical parameters that we have achieved are such that it is sometimes hard to believe in them, looking at the size and price of our transformers.

So far, so good, but why doesn’t anyone want to use toroidal transformers in their designs? The main reason for this is the prejudice, the fallacy, the misconception, as mentioned earlier. It is claimed that one cannot produce a good speaker output transformer based on a toroidal core, alone not to mention the context of a Single Ended architecture, where such a toroidal transformer does not even have the technical possibility to operate at all.

Therefore, we have decided to construct a Single Ended amplifier that is based upon transformers of our own manufacture. As a proof-of-concept, during the last year's Audio Show 2014 exhibition, we have presented the Laura amplifier - a non-commercial model, the sole purpose of which was to destroy the existing fallacy, the misconceptions. The resulting scope of interest has exceeded our expectations. Whilst the production of such toroidal speaker output transformers kicked in with full swing, a next, yet better idea came to my mind.

Let's create a new brand and design a tube amplifier, a retail version, made available at an affordable price, a construct which is the Polish alternative to the "Chinese" counterparts. And hence, the Silver Luna was born and came to be.

The records used for the test (a selection):

• Art Pepper, Art Pepper Meets the Rhythm Section, Contemporary Records/JVC VICJ-42524, K2 CD (1957/2006)
• Can, Tago Mago. 40th Anniversary Edition, Spoon Records/Hostess K.K. (Japan) 40SPOON6/7J, 2 x Blu-Spec CD (1971/2011)
• Frank Sinatra, Lost & Found | The Radio Years, Sony Music 8875147142, CD (2015)
• Kortez, Bumerang, Asfalt Records JB 029 2CD, CD (2015);
• Krzysztof Komeda, Ballet Etudes/The Music of Komeda, Metronome/Be! Jazz Records, BE! JAZZ 6087 CD, CD (1964/2014);
• Laurie Anderson, Big Science, Nonesuch 79988-5, „Expanded and Remastered for the 25th Anniversary”CD (1982/2007)
• Maanam, Miło¶ć jest cudowna, Kamiling Co | Pomaton 4601869, 2 x CD (2015)
• Milt Jackson Quartet, Statements, Impulse!/Universal Music (Japan) UCCI-9088, „More Best 50. No 38”, CD (1961/2001)
• Nirvana, In Utero, Geffen GED 24536, CD (1993)
• Suzanne Vega, Nine Objects of Desire, A&M Records 540 583 2, CD (1996)

Japanese issues available at

So let's start with a brief summary of such a comparison. And it will be really a short one. The Silver Luna does not have any existing competition in the area up to 5000 PLN, at least when it comes to tube amplifiers. Neither in terms of appearance, nor performance, and the more so, when it comes about to the quality of its sound. This aforementioned trinity is very coherent, and every aspect is refined. Obviously, all in proportions and within the accepted limits, those being the final price. But there is no gap, no dissonance between the sound and the sturdy workmanship, and indeed, we do know that cheap products from China are cheap inter alia because they do not pass rigorous quality control procedures. The end result is such that we usually wind up with multiple exchanges of a faulty unit, with repairs, and sometimes, also, with a general "farewell to Asia".

A few years ago I heard about an American manufacturer, called Rogue Audio, offering vacuum tube amplifiers with mid-level price ranges, and that it has decided to come back with its production to the United States. The explanation, as given at that time, was not as clear to me then as it is today. The idea being that the manufacturing costs (labor costs) in the United States have diminished, and hence the company no longer wanted to pay, cover the costs associated with the ongoing maintenance and improvements that needed to be carried out, conducted, after receiving each next consecutive batch of equipment that originated from factories in China. By bringing the manufacturing back under one roof, with in-house quality control, under the watchful eye of the owner, it turned out to be not as expensive as one would initially think. I believe that this is exactly the very same mechanism that works out so well for Fezz Audio, with the caveat though: that the company managed to omit the “OEM” phase entirely.

In this manner, we obtain a very fleshed out product with fine finishes, one with an incredibly natural sound. If you would like to describe it as a "tube" sound, so be it, that's fine. But let’s keep an open mind and our eyes on such products as the SoulNote SA300, or the SPEC, Japanese digital amplifiers which deliver a much warmer, more "tube-like" sound. But not only these, as I would also apply such a similar description to completely analog amplifiers from the German company ASR and others, such as for example the French Lavardin. The “tube-ishness” of the amplifier under test is characterized by a lack of sharpness and a slight enhancement of the mid-bass and lower midrange frequency ranges

The vocals are slightly zoomed-in upon and enlarged. The contrabass is also playing a tad closer and in a more intimate manner. But Hey! This is what we would expect of a vacuum tube amplifier, right? Even those who have a different vision of sound should also listen to what is happening here, because I'm talking about very delicate accents, only but slightly enhanced, without being intrusive. The warmth of the sound is of a general nature, and it is not just about rounding off the boundaries of the bandwidth. I would even say that the treble opens up very nicely, it is not lacking luster or openness, the sound is vivid and alive.

If we are experienced in audio, we shall probably quickly appreciate the naturalness of the communication. A beautiful characteristic, as it gives us a lot of freedom of choice as to the type of music material. Wonderful electronics, such as the new album from GAD Records with Claus Hertel recordings, Laurie Anderson, or the fantastic Kortes, all of these have been recreated with a large cubature, a high degree of spatially, in a very open, albeit slightly sweetened up manner. The amplifier obviously imprints its own sound signature, its character, on such recordings, mainly by achieving an even, uniform representation of the lower bass. This lower bass does not go down as low as in the case of some of the other powerful amplifiers out there, but this does not seem readily apparent, which I believe may be caused by the very active and energetic performance of the midrange. This is not an amplifier, with which we would want to test the bass foundations of Suzanne Vega’s recordings.

If we close our eye on this minor issue, the more so shall we appreciate that apart the bass, the differentiation of everything is very, very good. There is no question about recognizing the differences between various takes of Cortes vocals, how vocals are changing within the recordings of Sinatra, or what are the subtle differences in the recordings of the Can band. This differentiation is with a touch of special accent on the coherency and density. But we shall also find a high level of energy of the metal percussion plates and a nice opening up of the midrange. When the drums are hit, they have a high energy, they are quick. When the percussion brass is hit upon hard, it really sound like it.

Well obviously, one may also find records, which shall not playback so convincingly. But this does not mean that they will sound badly. It is just that we would expect of them something slightly different. Examples being like Nirvana’s In Utero, the recordings of Black Sabbath, or generally – any hard rock recording with a strong level of compression. This amplifier makes them all sound a bit too humble, mannerly, polite for my tastes. It does show the good side of these recordings, but without the lowest bass control, without the energy that is needed there. This does not mean that transistor based amplifiers, available at a comparable pricepoint, would fare any better. It is just the issue that after experiencing the magic that happens whilst listening to jazz records or other material, when we then switch over and listen to heavy rock, we seem to lack that same level of naturalness, that touch of awesomeness which we would expect of it.

Summary

Despite the moderate power output, this amplifier can play really loud, and when it goes into overdrive, it does so gently. This is manifested by a hardening up of the upper midrange. Under normal circumstances, you would not hear this. This is a rich, natural sound reproduction, with a well articulated midrange and an open treble. The amplifier is almost completely devoid of functionality as typical and known from other similar devices. Equipped with just three line level inputs, it has no remote control, no digital inputs. These are the drawbacks that need be accepted. But there is nothing to regret. If we can live with that, then please do listen to this amplifier, because it is a true killer.

The Fezz Audio Silver Luna is an integrated vacuum tube amplifier. Vacuum tube circuits are used to amplify the signal. Four EL34 power pentodes are used, two per channel, as well as two dual pentodes ECC83, one per channel, whereby one half is used to amplify the signal, while the other half is used as a phase inverter for the output for the output push-pull stage. The power supply is based on semiconductors. The input signal may be provided via three selectable line inputs. There are two speaker output tappings, both for 8 and 4 Ω. The unit is supported on four footrests.

The outside

The chassis base is comprised of a low profile, lacquered cuboid. On the front of it a logo is affixed, laser cut from a thick metal sheet, as well as two aluminum knobs. One used to change the volume, the other to select the input. The knobs are almost identical to those currently used by companies such as Ancient Audio in the P-3 and A-3, and refer us back to the 70-ies of the last century. On the back side of the unit there is the power switch, which is integrated with the IEC mains socket. There are also three pairs of gold plated RCA jacks and two sets of speaker output terminals.

Similarly as in other amplifiers of this type, the vacuum tubes are mounted on the top side. These are the EL34 power pentodes made by Electro-Harmonix and the dual triodes, ECC83, from the same company. We plug these into ceramic sockets with gold plated pins. The location of the tubes is somewhat irregular due to the placement of a circular power transformer shield box in the very middle, amidst between the tubes. At the rear, there is yet another, a longitudinal transformer housing, holding the speaker output transformers. Adjacent to the vacuum tubes we can see the measurement test points, as well as the trim-pot knobs that are hidden within the chassis. Each pair of output tubes need be “adjusted” by means of aligning the bias current. There is no provision for a protection cage to cover the tubes.

The Inside

As in every good amplifier, the circuit here is a simple system. Each amplifier channel has its own circuit board. Tube coupling is executed using WIMA polypropylene capacitors. The decoupling of the cathodes is achieved via very good electrolytic capacitors, the Nichicon Fine Gold series. The signal ir routed to each of the circuit boards via shielded cables from the potentiometer, a black Alps pot. An interesting observation – this is a motorized version of the pot, as if ready to be equipped with remote control. Maybe in the future there will also be made available a more expensive version of this amplifier with a remote control? The potentiometer is connected with silver cables to the mechanical input selector, also located on the front panel. This is connected with long stretches of interconnect from the back pane input jacks.

The power supply is assembled right in the middle, on a separate circuit board, and it is shielded by a thick sheet of metal. We have a a PI type filter, with a toroidal choke ( what else could be expected here?) and two filtering capacitors from the Slovak company JJ Electronics, known for its production of vacuum tubes.

This is a fantastic, simple design, one in which each element has its justification and is neither exaggerated nor scaled down. My respects.

Technical data (according to manufacturer)

Type: integrated stereo amplifier
Maximum Power: 2 x 35 W / 8 Ω
Type: push-pull, class AB1
Output Impedance: 4 Ω / 8 Ω
Inputs: 3 x RCA
Total Harmonic Distortion: THD <1%
Frequency response: 15 Hz - 77 kHz (-3 dB)
Power consumption: 150 W
Weight: 15.3 kg
Dimensions: 400 x 320 x 165 mm
Tubes: EL34 × 4, ECC83 x 2