WORLD PREMIERE

⌈ GERHARD HIRT knows the audio world like the back of his own hand. He works with many well-known technology companies, is the owner of a part of the former TESLA factory, manufacturing electron tubes, and privately he is a great fan of vinyl records. And he loves tubes. He founded AYON AUDIO in 1999, but already since 1995 he worked with another well-known tube company - Vaic, which he bought in 2001. Today, Ayon Audio offers electronic tubes (triodes), tube amplifiers, digital sources (with tube output) and loudspeakers. ⌋

ne of the oldest AYON AUDIO products is the Spirit integrated amplifier, launched in 2004. It was the first Ayon Audio's push-pull design - earlier, only single-ended amplifiers, had been produced by Gerhard Hirt and his engineers, and they manufactured tubes for their products too. The idea for this device came on the one hand from Ayon customers, and on the other from distributors, who - as disclosed on the You Tube interview asked him to develop a "more universal and affordable amplifier." That is how the Spirit (I) was born.

Spirit | It is a mid-size integrated tube amplifier with a semiconductor power supply with the KT88 output tubes operating in a push-pull mode. The power tubes operate in class A and there is a switch allowing user to choose between two operating modes - pentode and triode. The KT88 is a beam tetrode, but its mode of operation is defined as pentode. Three double 12AU7 triodes were used in the preamplifier and as drivers.

The device featured a high-class aluminum housing, which was still new for Ayon - earlier its amplifiers looked different – see 300B (HF | № 50). The appearance of the Spirit model was in line with what is currently a standard for this class of devices – input and driver tubes in the front, behind them power tubes, and in the back, output and power transformers. In the Austrian amplifier, this array was slightly modified in such a way that the power tubes were positioned on the sides of the input ones, not behind them.

After minor improvements – ultimately there were four tubes in the input stage, not three, and the KT88 operating mode switch was moved forward - the new version - Spirit II was launched. We had to wait much longer for the Spirit III, that is until 2010. In 2013, we tested its improved version III (New). It took Gerhard nine years to develop the Spirit V model. However, it seems it was worth the wait.

GERHARD HIRT
Owner, designer

WOJCIECH PACUŁA: V is the fourth version of Spirit.
GERHARD HIRT: Yes, there is no number „IV” in the series because the number 4 is associated with death in Asia.

How and when did this project start?
If I remember correctly Spirit was first introduced to the market in 2004. So roughly 15 years ago.

The design is still similar to that of the first generation?
No, not really. We started with power amplifier featuring a standard manual bias adjustment. It was a very simple circuit utilizing very simple technologies. We started to develop this product in 2003. It was our first non-SET amplifier. And our SETs were quite successful. Yet, the pressure from American market forced us to develop a simple, affordable, push-pull integrated amplifier. That's how it all started.

Three Spirit generations – I, II and III.

Spirit I was an immediate success. Some 3-4 years later we replaced it with second generation, the Spirit II. The design got a little bit more complex. Also this version was successful. And only then we began developing the Spirit III, that we based the latest model, Spirit V, on. And it was the III generation that was a true breakthrough for us.

First of all, because in this version we introduced the Auto-Fixed-bias solution with accompanying protective circuits. It took us whole five years to develop it, as there was no information how to make such circuit in any textbook. This solution was a true engineering breakthrough also because none of this circuit's elements operate in signal's path. We've been selling the Spirit III for nine years!

That's why you based the latest model on the Spirit III? Exactly. Several solutions we had developed for it turned out to be so good, that we could use them also for the new Spirit V. Obviously we looked for elements that could be further improved. But, to be honest, it was really difficult to do that. Considering the price range and the level of performance it was hard to find ways to improve this design further. We were not looking for ways to change the sound – that would be another story – but to improve it. And achieving real positive changes to the sound cost us years of hard work. We had to consider every tiny detail, prove-check every idea and ask ourselves, whether an improvement we achieved was actually good enough for the new model.

Let's take, for example, output transformers - we have invested over a year working only to develop new once for the Spirit V. We had dozens of prototypes that we listened to one by one. And then each next step was equally tedious. The driver stage - we included in its design all our knowledge of tubes. But it is obvious that each section must work well with the ones surrounding it - the driver must match the input section, the output tubes, and even the output transformers. You can achieve proper results only in one way, by countless listening,sessions.

Because measurements are only one side of this equation. One day you finish measuring and sit in front of the loudspeakers, asking yourself - what kind of sound moves me, what's working for me? And only then you start making real changes, and more and more changes. This amplifier was a real challenge for us. However, after all these years, after the success of the Spirit III model, we think that it will be a new milestone in this price range.

It features two separate power transformers and the power supply is 50% bigger. Output transformers are the very core element of this amplifier, a milestone. When building the V model, we thought about it the same way we think when developing our single-ended amplifiers. The volume control has also been changed. We have slightly improved the bias control system, and we have also slightly changed the grounding system. There are a lot of such small changes.

Once you've listened to it, you'll see that it sounds more like a SE amplifier than a push-pull. This is easy for me to say now, but getting these was extremely difficult. I hope that this amplifier will be part of our lineup for the next seven-eight years, maybe even nine :) Simply, considering its price, we've hit the wall with it. I don't think I could improve this design anymore. ▪

| SPIRIT V

The Spirit III was a very good amplifier. As I wrote in its 2010 review (for "Audio" magazine), it was a solid, reliable device that deserved “B+”. Its successor (New), however, changed the game - its design utilized some solutions originally developed for the more expensive Triton III amplifier, and for the Eris preamplifier.

In retrospect, however, it seems that something else was much more important - an improved version of the "Auto-fixed-bias" system and an advanced system that protects tubes. The III generation featured its fully automatic, new version for the first time. The Spirit V is based on it, taking from the III model everything that was best in it, adding to it some solutions from the most expensive amplifiers introduced to the lineup in the meantime and combining all these elements it into a new whole design.

Let me say it again, as it is important - Spirit from the beginning was a very good amplifier. With time, its sound, reliability and functionality were improved. However, I always felt that Gerhard made it by putting together elements taken from more expensive amplifiers. It produced great results, but it has always been a product with a kind of flexible "suspension" between the individual modules. It worked great, but it was always sort of a "puzzle" put together of elements taken from other project.

When I saw the Spirit V, when I touched it, turned it on, when I learned what was changed in it and how, when I finally listened to it, I knew that a certain stage had ended – it is a compact, well-thought-through design at every level - mechanical, electric, functional and - if I may say so - product's philosophy. Just a masterpiece.

Front | Spirit V looks a lot like its great-great grandfather, the Spirit (I). Its chassis is made of solid aluminum panels and quarter-sides that form the sides. In the front there are two knobs - volume and input selector. You can notice the first difference right away though - the alphanumeric display is gone and instead there is a red LED on the knob indicating its position.

Let me put it this way – an electronic (analog) volume control is a great, solid solution. But - Gerhard came to this conclusion based on numerous listening sessions - it can not replace a classic potentiometer. So he returned to the solution used for Models I and II, but in a newer version. And the LED? Its incorporation into the knob required many hours of designing work and many prototypes before the silicone sleeves of the power cables began to flex noiselessly and without getting damaged in a longer run.

Also the input selector features a switch, not relays - it is another modification resulting from the listening sessions. Next to it, there are LEDs indicating a selected input, selected "Triode" or "Direct" mode, i.e. a direct power-in, bypassing the preamplifier tubes and potentiometer. Why would anyone need it? Gerhard mentions two possibilities - to use an even better external preamplifier in the future or to use the volume control in the SACD player (CD).

Auto-fixed-bias | In the middle, between the knobs, there is a backlit company's logo. It is used to indicated the turn on and turn off phases – during them it blinks and the input signal is cut off. At that time the amplifier automatically measures the parameters of the output tubes and adjusts the anode and bias voltage for them. This is one of the advantages of the proprietary Auto-fixed-bias (AFB) solution, that Ayon Audio developed in-house.

This is an advanced system that should be calibrated after purchase in customer's room as the amplifier must "learn" the voltage value feeding the amplifier and determine the tubes power supply parameters in relation to it. The point is that tubes operate at 85% of their current capabilities, and not - as in other amplifiers - at 75%. In order not to overload the tubes, they must be constantly monitored - which is what AFB ensures. An additional benefit is that the sound does not change as the tubes age.

So the Spirit V is much more convenient to use - this is one of the things that I would like to particularly emphasize. Why? Because there are many people who love music, for whom listening to it is an important part of their life, who would like to try out a tube amplifier, feel its "magic" (real or imagined - this is another matter), but they are afraid of practical aspects of using tubes. They are not sure of their reliability, there are afraid of operation challenges, and a need of tubes replacement.

These concerns are completely justified, but in this case pointless. When choosing a tube amplifier one makes a significant change, similar to the transition from audio files to vinyl records - it's about a completely different thinking about audio. And the Spirit V offers us an opportunity to make such a transition as painless and even joyful as possible.

Rear | The rear panel of the amplifier looks like an audiophile's dream. First thing you may notice are high quality, easy to use WBT Nextgen speaker terminals, but after a while you will also notice elements that are quite rare in amplifiers - buttons, switches, and also an alphanumeric LED display. The latter placed in the front would presents volume level, and here it indicates the current operation and waiting time for Auto-fixed-bias and protection circuits. If one of the tubes has been damaged or if one of them is worn out, its number will be presented on the display.

But I also mentioned switches. One of them, described as "Ground" allows you to choose the type of grounding of the amplifier, ie how the chassis connects to ground. This solution is taken from recording studios, I also use in the Spheris III preamplifier. Since in recent years the usage of "artificial" ground increased, the amplifier is equipped with a suitable socket.

There is also a second switch - it is a novelty – one that allows user to adjust the amplifier's operation to the speakers one uses. Gerhard does not say exactly how, but only that that it changes output's damping. Let me remind you that a very similar solution, although in loudspeakers, was used by Mr. Karl-Heinz Finke - in the Borg. The switch in the Spirit V has three positions, one of which is for loudspeakers with impedance of 3 and 4 Ω, the other for those that drop below 3 Ω, and the middle setting does not make any changes to the output.

Tubes | I've discussed the most important changes that you will find in the V model. But the first thing that strikes you is the output tubes. All previous versions featured KT88 tubes, while the version III (New) allowed user to also use more powerful ones, KT120 and even KT150. "Allowed" did not necessarily mean the it was "worth it". While the KT120 was operating within the range of the amplifier's parameters, the KT150 would have required a much more massive power supply.

And that's what the latest version received. Gerhard says that the level of energy the amplifier is capable of delivering increased by 50%,, among other things due to the use of two large toroidal transformers in the power supply section. The power supply is so efficient that it required using a special system that would protect other devices in user's home against it, for example during a storm. So Ayon came out with proper protection circuit. The KT150 tubes come from the Russian company Tung-Sol, because it is their only manufacturer. Gerhard had access to them already one year before the official premiere and at that time he knew that this was the real successor of the KT88, and not - not so good, in my opinion - KT120.

The preamplifier stage features the 12AX7 tubes, which is a big change - from the very first generation of the Spirit the 12AU7 tubes were used. As drivers for output tubes Ayon now uses twin NOS 6SN7 triodes, as opposed to previously used 6SJ7. The unit we received for test featured Russian tubes from 1966, the 6H8C (6N8S).

| HOW WE LISTENED TO IT

The amplifier was brought to me personally by Gerhard Hirt, the owner of Ayon Audio - he brought, calibrated the tubes and discussed the amplifier with me. He smiled at the sight of so many Ayons on my Finite Elemente rack - in addition to the Spirit V, there was also the CD-35 SACD player HF Edition (№ 1/50), a two-box Spheris III linear preamplifier and the HE-1 two-box headphone amp - and only the latter did not participate in the test.

The Spirit V was compared directly to the "High Fidelity's" reference system consisting of the aforementioned preamplifier and the Soulution 710 power amplifier. Both amplifiers - tested and reference ones – drove the Harbeth M40.1 loudspeakers through the Siltech Triple Crown speaker cable. I also listened to Ayon on the using the Western Electric WA310 NOS cable and I have to say that it sounded really good.

The tested amplifier was placed on the top shelf of the Finite Elemente Pagode Edition rack and was powered using the Hijiri SM2R "Sound Matter" cable. It was tested in both modes - pentode and triode, but the description of the sound concerns the triode mode. I included the differences between them in a separate frame.

Recordings used for the test (a selec- tion)

• Fusion. Best Sound Selection, sel. Yoshiro Obara, Stereo Sound SSRR-12, „Stereo Sound Reference Records”, SACD/CD (2019)
• Alexis Cole, A Kiss in The Dark, Chesky Records JD366, CD (2014)
• Halina Frąckowiak, Geira, Polskie Nagrania „Muza”/GAD Records‎ GAD CD 095, Master-CD-R, (1977/2019)
• Pat Metheny Group, Offramp, ECM/Tower Records PROZ-1095, „ECM SA-CD Hybrid Selection”, SACD/CD (1982/2017)
• Sonny Rollins, Saxophone Colossus , Prestige/Analogue Productions CPRJ 7079 SA, SACD/CD (1956/2014)
• Tame Impala, Currents, Universal Music Australia/Hostess 4730676J, CD (2015);
• The Beatles, Rubber Soul, Parlophone/Apple/Toshiba-EMI TOCP-51116, CD (1965/1998)
• Voo Voo, Za niebawem, Wydawnictwo Agora 5903111492953, CD (2019)

Let's see: the Spheris III preamplifier costs PLN 139 900, its power cable - the Acrolink Mexcel 7N-PC9500 - another 20,000 PLN, the interconnect connecting the preamplifier and power amplifier – the Acoustic Revive Absolute FM - adds to this amount 39,900 zlotys, and the whole amplification part of my system includes still the Soulution 710 amp that adds another PLN 130,000 (when it was sold). I will not even mention the anti-vibration platform and feet used under the Ayon preamplifier. In total it is, give or take, 330,000 zlotys for the amplifier itself. And the contender, the Spirit V costs 24,900 zlotys. How did it make me feel?

First of all, I did not feel that I was losing something, I could not live without. The difference in sound was obvious, clear, immediate, but it was not even close to the absurd price difference. What's more - the character of the presentation that I have in my reference system was preserved. Not that the new Ayon amplifier pretended to be something that it wasn't, or that Gerhard Hirt tried to simulate the sound of the "High Fidelity" system in order to get a better result of this test (and it was planned as the official world premiere). If that were the case, if Gerhard did it "for me", my ego would grow to the size of an Olympic pool, and I could probably retire.

However, this wasn't it. It's just the sound - I mean the sound understood in absolute terms – with the 'V' it is so good, so convincing that you need to listen to the more and more albums, it's a sound with high aesthetic qualities and, in addition, incredibly believable. Is it realistic? - This is a philosophical question, because the sound replayed mechanically is never truly realistic. In this sense, it is also not realistic in this case. It can be credible though, just like with the Spirit V.

The sound of the new amplifier from Gratkorn in Austria is outstanding, not only in its price category. The device made a great impression on me, just like the Leben CS600X tested just a month before. However, it sounds different enough from the Japanese master that it will be easy to decide which device meets our expectations. I would also like to add that the Austrian integrated is much more versatile compared to the 600X.

The sound of the Spirit V amplifier is very saturated. It's more and more often that I mention this quality in my reviews. But there is more to the Ayon - it offers a sound saturated in a beautiful, wise way. This is the thing I usually look for in the devices at the beginning, because it shows the capabilities of the device in terms of resolution and sound richness. Without it, we can only talk about "presentation", but certainly not about a "credible presentation." This is something that has been changing the fastest in high-end devices in recent years and it is an indicator of progress. It has also been changing in Ayon Audio devices - both digital and analog ones.

So we get a very resolving and saturated sound. For beginner music lovers and audiophiles, one surprising thing is that at first it seems that the amplifier is not particularly detailed. Although in pentode mode it shows more details, you can still talk about "dark" sound. One in which everything has the right proportions, and the details do not attract attention to themselves. What's more important is the kind of "story" we get with consecutive albums, not the way of telling it.

One listens to this story with real pleasure. Mainly because it is a warm, dense and smooth sound, and such comfort makes listening better, deeper, allows a deeper experience. Nothing distracts listener from music, neither the mechanical side of music reproduction or anything around us. But, unlike with the Leben, warmth and smoothness are only one side of the story, because the other is the high dynamics and perfect bass that we get with the Spirit V.

The sound attack in the lower range is slightly rounded, but - to be honest – I liked it. Yes, in comparison with the Soulution 710 I could hear that it was after all a tube amplifier and one of not particularly high output. On the other hand, however, the differences were not large, I would say that within the conventional boundaries of "correctness" it is closer to my amplifier than many other devices. This is something really rare.

The bass I'm talking about is deep and full. It allows for comfortable listening to a wide spectrum of music. It beautifully showed the acoustic bass on the Pat Metheny Group album entitled Offramp on the Tower Records SACD. It equally well presented the momentum, fullness and "width" of music from the Tame Impala's Currents, and this is just a regular CD release. The thing is that the low range is beautifully combined with a lower midrange. The amplifier doesn't artificially add weight to the bass, and yet it does impress from the very first moment.

The midrange is very natural. I could say that it is "warm", but I do not know if it would be fully justified. Because this is true for the Leben's CS600X - it's a characteristic feature of this Japanese amplifier - and Ayon plays "wider", both in terms of timbre and dynamics, and thus focuses our attention on the midrange in lesser extend. Nothing here is presented closer to the listener or added weight to. The small, shown from a distance, Halina Frąckowiak's vocal from the Geira remaster remained quite small, it was not artificially enlarged, nor pushed closer to me.

On the other hand, Ayon never brightens up the sound. Even in the Nowhere Man from the Rubber Soul by The Beatles, where the vocals were recorded quite high, and additionally in one channel, which made them quite “screamy”. The amplifier showed this feature, I could not listen to it very loudly, but after reducing the volume level to a reasonable level everything "clicked" into place and listening wasn't annoying anymore. The reviewed amplifier simply did a good job playing the track in an accurate way which was later confirmed by the Girl from the same album - air intake was natural, had a musical sense and did not jump out from the rest.

Let's get back, however, to the lack of brightness. Similarly, it is in an absolutely balanced and professional way, the voice of Alexis Cole from the A Kiss in The Dark was presented. This recording was made using the "artificial head", as binaural, on the so-called "hundred". To keep the right balance between the instruments and the vocalist, the instruments were moved further into the room, and Cole was positioned exactly in front of the "head" with microphones. The sound from the center is therefore small and fairly quiet, and the instruments, especially the saxophone, are presented as richer and fuller because there are long reverbs there too; the vocal is also much drier.

Ayon presents such nuances effortlessly, does not make us focus on some single element. Drawing a full panorama, it put all the information in it, which allows listeners to create a complex picture in their heads. This is a very high level of performance, usually associated with advanced high-end devices. Because Spirit V is a high-end amplifier. It may not cost as much as other amplifiers in this group, but it has everything that they do: resolution, fullness, density, dynamics, and above all, it plays music in such a way that one can listen to it in a great comfort.

Plus-minus | What can you expect, by going up the price list? The reference system sounds more focused and at the same time even more natural and soft. By focused I mean that the instruments have a more pronounced "bodies” that are more three-dimensional, while the Ayon slightly – but only sightly, compared to the much more expensive reference system – blurs them. My system also better conveys everything what happens deeper in the stage. Ayon is excellent in this respect, it is very good, but it can be done in an even better way. My three-box amplification has even more breath, even more internal peace, you can't have that for less money.

| SUMMARY

The reviewed Spirit V from Ayon Audio offered a high quality, refined performance. If someone tried to force me to choose between it and the Leben CS600X I would not be able to do it. On the other hand, it is the Spirit V that seems to me a much more versatile device, which while preserving everything that we get with Leben, adds even greater momentum and better dynamics. What's more, it is also more differentiating. And - it's important - it has much better protection for the tubes, which gives users exceptional comfort. As always, you will have to decide for yourself.

This device offers a beautiful sound - in such cases as this one, one can see that progress in audio is real and that it is true that newer products are better performers than older ones. What you get here for PLN 25,000 is a true high end device. RED Fingerprint is a must in this case. To emphasize what Gerhard and his team managed to achieve this time, we decided to add a golden crown to it :)

| DESIGN

Mechanical design | Most details of the mechanical design, appearance and functionality have already been described. Now I shall add that knurled, large knobs look really cool and you should appreciate them - they are expensive to manufacture, that's why manufacturers are reluctant to use them. The idea for a placing a LED in the knob is not new, it is one of the oldest methods of indicating the volume, but an almost forgotten one - due to the usage of integrated resistor ladders, the manufacturers use displays to present information regarding volume level. And again - such a diode is a big technological challenge, which is why it is reluctantly used by producers.

Electric design | But it's time to tell you more about the electric design of this amplifier. The entire amplifying stage is made up of tubes operating in class A, triodes and beam tetrodes operating in triode mode (one of the grids is grounded). The power supply is a solid-state one, but it is one of the secret ingredients of this amplifier; the other is the automatic bias system and control of tubes parameters.

The base of the power supply are two, very large toroidal transformers, placed one above the other in a large housing behind the tubes. After rectifying the voltage, it is filtered in a classic Pi-type choke, consisting of capacitors and chokes - power tubes and a preamplifier section feature separate chokes. The heating voltage is rectified and regulated - again both, for the preamplifier and for the power amplifier. All power supply is controlled by a microprocessor. The company gave the name to this solution "Intelligent Auto-Fixed-Bias" (AFB). This is the Ayon Audio's crown jewel.

If I say that almost the entire interior of the device is one big power supply with protection systems, it won't that much of an exaggeration. The power supply is based on two large toroidal transformers, enclosed in a housing outside, and they are supported by two, chokes hidden inside. The AFB occupies several small PCBs, among them there are also PCBs with relays that switch on the individual voltages for the input and output tubes. All systems have been assembled on printed circuit boards - but not on a few large ones, and on many small ones, separate for each subsystem. It makes servicing job (if necessary) easier, but also physically separates individual sections.

The amplification circuit itself is relatively small. From the inputs signal goes to a small PCB with relays, then to the Alps potentiometer in the front panel and from there to the input tubes. The signal is transferred via SoundKlang microphone cables. The individual stages are coupled with small Mundorf propylene capacitors from the MCap series.

The design of this amplifier is complex, but the complication applies mainly to the power supply section. The amplification circuit itself is relatively simple. There are a lot of cables, PCBs and circuits there - the whole has been arranged in a very good way.

Remote control | The RC-4A remote control can be used with several Ayon devices – my Spheris III preamplifier included. It is small, made of aluminum, and it sports just five buttons. Two of them allow you to adjust volume level, one is for mute function, and the other two are used to select a sort of device one wants to use the remote with. ■

Technical specifications (according to manufacturer)

Frequency range: 10 Hz – 60 kHz (-3 dB)
Output:
• pentode mode: 2 x 65 W
• triode mode: 2 x 40W
Input sensitivity (@ full power): 500 mV
Input impedance (1 kHz): 100 kΩ
NFB: 0 dB
Volume control: Alps pot
Remote control: yes
Inputs: 3 x RCA, 1 x XLR, 1 x Direct In
Outputs: 1 x Pre out
Dimensions (W x D x H): 480 x 370 x 250 mm
Weight: 33 kg