When review schedule was set for the Goldmund Telos 360 Universal Mono Amplifiers I was really looking forward to explore what these power amplifiers will bring in terms of high-end audio performance and on what level they will be ready to perform. Yes, there was strong expectations with such product coming from this long standing Swiss high-end audio company.
History of Goldmund Telos 360 points way back towards the 1982. Goldmund amplifiers went through many refinements up to present time and prolific sound outcome is no coincidence. In order to prepare the conditions on the proper plane I’ve partnered them with my trustyworthy Robert Koda Takumi K-10 preamplifier. As you’ll learn through the review this was mandatory needed.
MEET THE TELOS 360
The Telos 360 is latest new product coming from the long standing heritage of the Goldmund power amplifier line, that was introduced for the first time by Goldmund back in 1982.
Interestingly and intriguingly Telos 360 uses very similar circuits, that was designed for the original Goldmund model. Over the years only fine refineries were implemented by the nine generations of Goldmund engineers. Each engineer added a slight improvement, that kept the original sound DNA, but introduced viable sonic advantages.
From the start Goldmund team wanted to create power amplifier with much more speaker control - acoustical damping, compared to existing designs from the competition. This translates to much easier handling of the speakers and preservation of the original musical signal.
Speakers are by their nature a heavy load and totally dependable of the proper power amplifier power. Generally and closely connected with brands’s electronic philosophy, speaker control can be improved by quite few factors:
• The damping factor, widely advertised in the 70’s
• The TIM distortion cancellation, originally promoted by Matti Otala
• The amplifier speed (node delay)
• The feedback delay
Except of few true gems there was not really much advancment over the years in the development of the power amplifiers, but a lot of eschewing of the old ideas.
Goldmund pushed their efforts with the elimination of time distortion that is closely connected with the unnatural delay of the higher audio frequencies, being closely related with the low frequency specter. This obviously steps into domain of pyshoacoustics and Goldmun amplifiers sports a bandwidth of approximately 3 MHz, that is by the brand understanding almost 100 times higher then of a typical power amplifier.
In their tests Goldmund amplifier have shown how 20 kHz tone is delayed only 100 ps relative to a 20 Hz tone…
Goldmund engineers have devised special protection circuits that enable the company’s amplifiers to deliver their extremely high power safely and to preserve both the amplifiers themselves and the speakers to which they are connected. Goldmund’s unique Mechanical Grounding technology practically eliminates sound-smearing vibrations inside the amplifier. Finally, as part of its Proteus project, Goldmund is now using digital audio processing inside its amplifiers to compensate for the driver characteristics and positioning of its speakers.
Let us look a even a bit deeper into the the Goldmund design philosophy…
All audio amplifiers are capable of reproducing the full range of audible sound from 20 Hz to 20 kHz. However, these amplifiers do not allow audio signals to pass without alteration. In order to prevent a damaging phenomenon known as oscillation, almost all amplifiers incorporate filters that block frequencies above the audio range. Although these filters may not affect the linearity of the amplifier within the audio band, they have a significant and measurable effect on the phase of sounds within the audio band.
As a result, the treble frequencies are shifted in phase—in other words, delayed—relative to the midrange and bass frequencies. Such phase and timing errors do not exist in nature; whether you are listening to the sound of a voice, a violin, or a jet engine, all frequencies emerge from the source simultaneously and arrive at your ear simultaneously. Thus, the brain is particularly sensitive to timing and phase errors.
Goldmund engineers have found out that audio amplifiers must have a bare minimum of 10 times the bandwidth of audible sound in order to avoid plainly audible phase errors. In order to prevent any possibility of phase error, we have increased the bandwidth of our amplifiers to approximately 3 MHz, more than 100 times the audible bandwidth of sound. Thus, phase errors in the audible range cannot be measured or heard.
Delivering such extended bandwidth from a high-powered amplifier is a difficult engineering exercise. It starts in the amplifiers’ power supplies, which in Goldmund amplifiers must deliver the full output potential within a mere 400 ns.
To achieve this goal, the power supply uses multiple smaller transformers in the place of a single large one. Smaller transformers charge and discharge more quickly than larger transformers, and produce tighter, better-contained magnetic fields that are less likely to interfere with other amplifier components. Instead of using one or two large, slow-acting capacitors for power storage and filtering, Goldmund uses dozens of faster, smaller capacitors.
Because Goldmund amplifiers have a bandwidth normally associated with high-frequency radio broadcast equipment, even the spaces between the components and the circuit-board traces are critical. Errors in these design parameters would result in filtering of high frequencies and, therefore, phase errors; they could even introduce the possibility of amplifier malfunction. Thanks to their years of experience and experimentation, Goldmund’s engineers are among the few capable of designing these high-power, high-bandwidth circuits.
An amplifier’s ability to move a speaker cone forward or backward is important, but so is its ability to stop a speaker cone from moving.
Speaker cones are, in effect, spring-loaded; thanks to the compliance of the surround and spider that attach the cone to its basket, a cone can bounce back and forth, an effect that smears audio transients. Fortunately, an amplifier can act as a brake on a moving cone. This is what we call “driver control” or, even more appropriately “Acoustical Grounding”.
After the electrical force from the amplifier moves the speaker cone, the spring action of the cone’s suspension pulls it back to its original position. As a result, the driver’s voice coil moves in conjunction with the driver’s magnet, generating electricity that flows back into the amplifier.
Ideally, an amplifier’s output would appear as a perfect short circuit to any electrical energy flowing back into it. It would thus block the generation of electricity and act as a brake on the moving cone. Without such damping, the cone would “ring”, or oscillate back and forth until the “Perfection in an imperfect world” energy built up in the cone’s suspension is dissipated. The measure of an amplifier’s ability to prevent such oscillation is referred to as damping factor; thanks to the acoustical grounding technology developed by our acoustic laboratory, the damping factor of a Goldmund amplifier is greater than that of any typical audio amplifier.
In the audio field, Goldmund amplifiers are unique in their ability to deliver extremely high power—up to 5,000 W in the case of the Telos 5000—at the extremely high speed necessary to achieve a 3 MHz bandwidth. In order to prevent dangerous malfunctions inside the amplifier, and to prevent damage to the speakers connected to the amplifier, Goldmund has developed the most advanced protection circuits found in any audio amplifier. Amplifier protection circuits must work quickly, detecting and rectifying problems before they can be heard, and before they can damage a speaker. In a conventional amplifier, these circuits must react at a fraction of the 0.05 ms it takes for a 20 KHz signal to rise to its peak power. In a Goldmund amplifier, with a rise time of 400 ns (or 400 billionths of a second), the protection circuit does its work within a mere 40 ns.
The protection circuits temporarily shut down the amplifier if any of four conditions are present: an output overload (power above the amplifier’s maximum rating appearing at the output terminals), a thermal overload (temperatures hot enough to damage the amplifier’s output transistors), or the presence of excessive high- or low-frequency energy at the amplifier’s input or within its circuitry. None of these circuits is connected directly to the audio circuitry, so none can affect the sound of the amplifier.
Heat is the principal enemy of performance and reliability in an amplifier. It is well known that heat can destroy electronic and electrical components. What is not so well known is that it changes the value of resistors and the gain of transistors, thus forcing the circuit to deviate from the ideal performance its designers intended. Goldmund amplifiers minimize heat buildup by mounting the MOSFET output transistors on a large, gold-plated copper heat transmitter that carries heat away from the transistors more quickly than a traditional aluminum heat sink can. The transistors are mounted using specially treated Kapton isolators, which provide a higher thermal transfer rate than typical mica isolators.
Goldmund also use proprietary technology in our resistors to maintain consistent performance through a wide range of temperatures.
Goldmund Media Room Application
The Telos circuit appears in all the Media Room amplifiers called the U-Telos. Each of these revolutionary amplifiers includes:
• 1 D/A Convertor board using the Alize 7 Goldmund D/A technology,
• 1 DSP board giving each channel its own frequency and time response parameters (so it
includes the crossover of the attached speaker),
• 1 Telos amplifier board, of the latest technical evolution.
The advantage of the U-Telos for the Media Room is that each speaker is treated individually, keeping a possible multiplication of the channels up to one channel per speaker.
“Perfection in an imperfect world”.
In addition, the DSP circuit is used to monitor the playback level of each individual driver in order to protect it against overload and maintain its long term integrity.
All of the U-Telos installed in a media room are linked by an Ethernet connection to the central room controller which can detect any anomaly and advise the service center without interrupting the room functioning.
Latest Development of the Telos Technology
In 2010, the latest Telos amplifiers, the Telos 350 and Telos 3500, include an optional pluggable DSP board, just like the U-Telos amplifiers of the Goldmund Media Room. Connectable to a laptop by an USB connector, the future DSP board will allow Amplitude, Phase and Delay to be adjusted to set the Telos 350 and Telos 3500 in any configuration, including a complete Media Room environment.
Taking Goldmund on sole performing ability, it is was the fairest an most needed thing to pair it with the proper preamplifier, that can reveal any shortcomings or true benefits. With my Robert Koda Takumi K-10 preamplifier that is close to the pricing at 32.500 EUR compared to the Telos’S 36.000 EUR, the combination was of proper balance and synergy. They locked with each other via core value gain transfer and K-10 managed to induct its vibrant handling of the harmonics and energy flow.
Telos 360 power amplifiers as mandatory need a proper match and without such paired synergy they will act accordingly. I’ve tried them with few of the lower lever amplifiers and sound outcome was something completely different. With the most familiar music there was no instant interlocking and transfer of the musical flow. Telos 360 managed to shown some of the qualities, but not even remotely on the level as it happened with Takumi K-10.
Telos 360 needed about 20-25 minutes to warm up and come into the stable operation. After that my listening notes shown no shifting, no drifting :).
Telos 360 won’t resolve with ultimate power that could tame big speakers of monstrous size and appearance. They were leveling more then well with Kaiser Kawero Chiara’s and Ubiq Audio Model One speakers. Great synergy with Chiara’s was no happy accident as Rainer Weber used exactly this amps as steady partner with the development of Kaiser Acoustics stand-mount monitors.
It always comes down to the system synergy and Telos 360, Robert Koda K-10 and Totaldac d1-six created a close and refined link ready to serve combined efforts with a sense of scale and drama that embarked many virtues of grander insights of the reality.
Telos 360 open nature and transparent charasterc strive for some non artificial warm insertion. This either calls for tube preamplifier or tube DAC/Phono stage that will bring a tint of the natural warmness. Then Telos’s were acting like tamed contenders.
Goldmund comes as different kind of Swiss luxury high-end audio, musical box. You’ll won’t find innards as complex or parts driven as Soulution, it’s of completely different approach then legendary FM Acoustics, miles away from dartZeel’s DNA and of different scale of CH Precision impact to name a few.
With its measured 8 Ω: 300 W of power a few watts seems to be missing in action, reflecting with the size of power supply and everything “inside of the box”. Goldmund clearly follows their own path focusing more on the optimal balance between the real world power and so called refined, smoother performance. Despite its intrinsic open and transparent nature, there was always a portion of mesmerizing roundness in play that could neither be pinned down to the saturation or over briteness.
In my role as reviewer, time spent with Telos amps came as a great addition to the upper echelon power amps exploration. More then often I’m questioned and reasoned about existence of such pricey high-end audio products and before even getting into the value, pricing and labeling, I’m first and foremost interested in performance and what any of these top tiers can bring in the designated ultimate sense. Recreating of the massive portion of the grand illusion and sense of reality comes at the price. I’m not offended or worried about the pricing issue in similar fashions as a real car enthusiasts don’t mind pushing the pedal to the metal with the utterly priced sport cars when such possibility comes to place. They want to enjoy and experience the driving while it last.
Its about the instant probability and what is possible to achieve. In the upper echelon there are different sets of rules in play and one can either argue or embrace them. Apart of selected, ever criticizing audiophile crowd, my utmost respect goes to the genuine high-end watch and car connoisseurs. Despite not being able to afford much of the bespoke creations they respect them and cherish bespoke products without envy and with pure enthusiasm.
Its hard to argue with the Goldmund’s heritage even if might be aligned with cold logic and not favorable towards everyone.
My gripe with Telos 360 comes with the power transformer purr that could be related with 220/230 differentially. My electricity quality is on the level, that I would call continuous. Without the stable handling of power conditioner there was an audible transformer sound that disappeared instantly when power conditioner was inserted. Sonic outcome was untouched, but I’m advising to anyone that is considering the Telos 360 to have proper power conditioner on hands in order to ensure the absence of the purr.
Coming as descendant of more then two decades of slow but wisely paced power amplifier product development, Telos 360 offers a great insight into the Goldmund sound orientation. Telos power amplifiers unlocked the understanding of company flagship amplifiers with grand portion of their impact. Complete Goldmund line shares the similar DNA, but with the scalable proportions dedicated to each units.
Telos 360 design cues are following the understated approach via more Swiss industrial look. Stylish, but more utilitarian aesthetics are upgraded with the addition of golden plate in the middle of the front plate adding a certain exclusivity.
This was very interesting experience and a journey towards the understanding and experiencing the Goldmund sound potency and audio impact. There are many high-end and ultra high-end companies joining the “dandy” club and they’re pushing hard the industry norms with the unique, potent and musically empowered amplifiers. What some of them do not have is heritage and brand recognition, but the path leading up to the top seems to be much more shorther then in the past.
Self proclaimed or once given throne must be defended with more then just clever tactics. Times are changing and so are our expectations with the higher priced high-end audio gear. Music lovers and audiophiles that can go beyond lurking and actually afford such devices are more and more in the search for more meaningful experience, story behind the brand and actual stand out performance. Not slight performance shift but massive improvement over the established norms.
At present times each high-end audio company must fulfill a number of important fundamentals; high performance, the strike of reality, uniqueness, exclusivity, luxurious appeal, handcrafting etc. Ultra high-end audio gear is clearly out of reach of mortals and connoisseurs of taste and funds to spend are coming with already established set of norms. In order to stay on top and among few chosen ones continuous momentum is needed and in few years we’ll witness different reality in action. This will affect a lot of high-end audio brands.
In due time I’ll reveal more palpable and realistic side by side real world performance challenge with the amplifiers like Vitus Audio, FM Acoustics, Gryphon, Thrax, Robert Koda and so on. It will be an interesting exploration without any hidden agendas.
Final judgment falls into the domain of people in search of proper balance of performance, luxury and specific sonic virtues. The Goldmund Telos 360 Universal Mono Amplifiers sums up in self contained package that represent brand’s vision, sonic orientation and their perspective of the high-end audio.
Text: Matej Isak
Retail price: 36.300 EUR
Nominal line voltage: 117 V, 234 V
Separated ground and earth signal
Rated Power Consumption:
IEC 60065, 1/8 Output Power at 8 Ω: 150 W
Max Power Consumption:
IEC 60065 at 8 Ω /1% THD: 450 W
Green led for power
Orange led for locking signal
Red led for error
Power cord: universal socket 3 lugs.
Output speaker 2 x 5 ways post in parallel.
Analog input RCA connector
Digital Spdif input and output RCA connectors.
Switch between analog or digital input.
Switch right or left channel selection from the Spdif input.
Max level before clipping:
1 % THD, unloaded: -6.6dBFS
Max level before clipping:
1 % THD, unloaded: 56 Vrms
FPP Goldmund at 8 Ω: 300 W
20 Hz - 20 kHz, unloaded: +/- 0.06 dB
DIMENSIONS & WEIGHT
31 W x 38.4 D x 23 H (cm); 20kg.
3 year parts and labor.
Research & Development, Manufacture
Digital Audio SA
3 chemin du Pre Fleuri
CH - 1228 Plan-les-Ouates, Geneva