GamuT D200i power amplifier

22.01.2013

For a strange irony of fate, I have often bumped into the GamuT brand. In fact, I have listened to many systems with a strong presence of the Danish components and, until this test, I have owned a pair of GamuT Phi7 loudspeakers. I must say that both the electronic devices and the speakers have always offered high quality standards under all the founding aspects of the matter. If it is true that, when you are about to review a blazoned, hence very expensive apparatus, you feel scared by the mantra question: "What if it does not perform well?", with the D200i, object of this review, I feel completely at ease.

 

Notwithstanding the titanic dimensions, the solidity of the chassis and a weight of 34 kg, the amplifier shows a sober elegance. Smack dab in the middle, as Ry Cooder would say: on the 10 mm aluminum frontal stands out a vertical inlay work where, on the top are the on/off button and the blue LED, whereas beneath are the logo and the model. The heatsinks occupy the entire side flanks. The lid, fixed with sixteen screws, is particularly damped. The back panel hosts, besides the IEC mains input, two RCA and two balanced inputs together with a pair of strong WTB speakers terminals: one named normal and the other direct. The interior is very intriguing and stimulates numerous staring points. The configuration is dual mono and the symmetry is almost perfect. The circuit boards at vertical module facilitate any access and upgrade. The space is largely occupied by the power supply section that is electrically isolated through a stainless U-shaped cap. The power supply comes to the GamuT through two huge 500 VA toroidal transformers and two pair of well dimensioned filter capacitors blocked by aluminum clamps shaped on the cylinder profile, for total 32.000 μF of capacity. At the inner sides of the cap are mounted four rectifier bridges, at which ends are soldered in parallel four Rifa PME 271M anti-noise capacitors that probably act on the stage impedance by limiting the value to the high frequencies. The amplification modules, put laterally in vertical position, display a great use of Wima capacitors and low tolerance resistors, each of them provided with six transistors that drive the output stage transistors.

 

So far, we can say that the described parts are coherent with what we can expect from an amplifier of this category. But the GamuT puts on the table an ace poker which makes of it a very original, winning and charming product.

 

Asso di Picche

The most part, if not all the so-called high power amps, use large multitudes of transistors that operate in parallel with the purpose of developing the estimated power, with consequent obvious problems of matching. This solution totalizes a huge availability of watts, but to the detriment of detail and precision. Our power amp uses two single huge APT20M19JUR mosfet transistors per channel, made to be employed into the switch power supplies. A push-pull amplification stage, operating in class A, drives the output stages. It works on a reserve that is 15 V higher than the reserve of the next stage and allows the full control of the mosfet transistors and the handling of the input high capacity when the component reaches the maximum level of energy distribution. All that becomes a power of 200 W into 8 ohms, that duplicates into 4 ohms and almost the 700 W into 2 ohms. Hence, it can control a current of continuous 100 A and a maximum power output of 300 A, with the ability of dissipating 500 W at 25° C of temperature. This approach to the use of the single transistor constitutes the way, as affirmed by the designers, to obtain a sonic perfection, which arises when is reached a harmonization between the fluid delicacy of the tubes and the pure power of the mosfet transistors.

 

Asso di Fiori

The GamuT D200i has a sophisticated protection circuit, which intervenes through thermal and electric sensors dedicated to the recognition of eventual situations of DC error, high level subsonic or ultrasonic signals, temperature, low impedance loads and short circuits. In addition, the voltage, the current and the phase are monitored. In presence of one of the mentioned conditions, the protection will make the input signal silent, or it will open the output relay. In presence of too low impedance loads, the protection starts a mute state that lasts one second. In this way, you can be sure to listen to a clean and undistorted audio signal. If you perceive one second of silence while the music is playing at high levels, this means that the protection has sprung into action with the purpose of safeguard the tweeters. Many amplifiers generate some clipping when the maximum level of power is exceeded. This phenomenon transmits to the high frequencies a big quantity of energy that can burn the tweeters. The protection constantly verifies the energy that exceeds 20 kHz, not perceptible by the human ear but seedbed of high distortion, and intervenes to reduce the fringe. The device can also activate when you are listening to warped vinyls without using a subsonic filter. For this reason, it is opportune to remember that, in order to consent the reduction of the warp effect, the resonance frequency of the tonearm/cartridge ensemble must be comprised between 8 and 12 Hz.

 

Asso di Quadri

The technique of collocating a coil in parallel with a resistor between the amplification stage and the output connector is common to all the power amps, since it represents an effective solution to protect the amplifier against the high capacitive loads of loudspeakers and cables. Unfortunately, the cost price is a sensible reduction of sound fidelity in correspondence of the high frequencies range. For this reason, to one protect output, called normal, it has been added a second output called direct: both are an ideal configuration for a bi-wiring connection with two couple of cables. The filtered termination is dedicated to the low line, the direct one to the mid-high line. But the GamuT D200i, with its 700 W of maximum power and the 300 A current peak, if matched with a loudspeaker with limited impedance, can transform itself in a deadly weapon and destroy whatever speaker. The value of 1,5 ohms has been elected as impedance threshold beneath which there is a further protection that has not to be considered as an operational limit, but as the confines of a segment within which the power amp can easily drive tough loudspeakers, electrostatic included.

 

Asso di Cuori

The fourth ace is, in my opinion, the designing gem of this splendid machine and pertains to the gain. Many electronic apparatus, both tube and solid state, are often sold off by users and critics as not performing. More simply, we are dealing with cases where the factor of the sensitiveness has not been considered at the moment of the insertion into a system. If a preamp has a very high or quite low gain, it cannot be connected to a power amp that has the same attribute and vice versa. The misunderstanding emerges more evident with some brands that make the same machines but with different sensitiveness. A suggestion for the buyer is then not to follow a device just because of his name, but to concentrate on the electric values, in order to concretely and empirically evaluate the real possibilities of assembling a correct and coherent system. A High-End budget set, respectful of the electric interfaces and of the gain balances and input sensitiveness, will always perform better than an improvised aggregation of slick brands. The GamuT has a gain adjustable through one switch for each channel, put on the side top of each amplification board, hence easily reachable, in the respect of the stereo balancing. The levels, besides the OFF position, are set at -6 dB, regulated by the company, and -12 dB. This flexibility allows an adequate matching both with a preamp with limited gain, like a passive preamp, and with sources that are provided with an output level that can reach four volts. The maximum gain declared by the manufacturer is 35 dB.

 

At this point, what makes the scene is the fifth element, the coup de théâtre. GamuT proposes, at the end of the user manual, a list of recordings used to test the sound quality of the amplifier. As they are difficult to find, they are proposed on CD version, with the invitation to find the vinyl version meant as superior. It is a list to take as universal reference to test the limits of whatever High-End system: a dangerous game, but intriguing, as the company says, from the subtle to the outrageous. I took up the challenge, I like to play and besides I own some of the titles in LP version.

 

First, the run-in is very laborious and seems never ending. It takes at least one hundreds of hours and you can perceive the changes on the fly also while you are listening. An interesting experience that drives out the doubts that the hi-fi components have something of humanoid. For the GamuT D200i I would be tempted to coin a new measurement unity: the cubic meter. The sound propagates in the room per cubic meters, without omitting any dark corner, riding out every obstacle, every barrier made by materials and furniture. The music wraps you physically, like being immersed in an amniotic liquid, because the expression is sweet, relaxing, delicate, oriented towards a sense of quiet, very intimate.

 

It also happens with the only rock record suggested in the list, Dire Straits, homonymous, Vertigo 6360-162, LP 1978, German issue. The sound is vigorous, intense, terribly dynamic and, also at very high volumes, always clear and controlled. The rich airiness and harmoniosity emerge and never exceed. This machine operates a sort of surveillance on the sound emission and soften all the electric and colored asperities that are a typical feature of the solid state electronics, without getting unbalanced towards the exaggerate warmth of certain tube devices. No hint of distortion or weave opacity. The imperfection are upstream, I mean those imperfection born in the recording studio or during the mixing. The track Six blade knife, which has been probably recorded with an analogue console, unfortunately trails behind a light tape hiss, but the instruments and the voice are simply touching and perform far better than the successive reissues and computerized remixing.

 

I put now on the platter two editions of the same record: Stan Getz/João Gilberto, Verve 1964, 2304071 German edition and 2317009 English edition. Getz, already in 1963, with the issue of Jazz Samba, always for Verve, had a role of protagonist in the revivification of the Bossa Nova. With this work, he consecrates it, not only as something to preserve, but also as a style very close to Jazz. Thanks to the involvement of Brazilian artists like Gilberto himself, Antonio Carlos Jobim and Astrud Gilberto, João's wife, he gives us an absolute masterpiece, which will insert the Bossa inside the musical life of North America. Furthermore, Stan's approach to the tenor sax, of cool school, and, in particular, the natural ability of expressing himself in controlled vibrato and straight tone form, will give a very strong impulse to the growth of this music and to its diffusion. The sound of the wind instrument moves in parallel with Gilberto's voice, in an extremely relaxed way. The air hovers without any effort, both if it comes out from the tube sax and the vocal cords. The feeling of this record is very hot, in a friendly mood, almost familiar. There is also the track Girl from Ipanema, which gives prestige to the GamuT D200i playback. The comment of the company about the recording, through the manual, is entirely sharable:" Many years later, it still allows you to dim the lights, make a nice cool drink and imagine you are in Brazil with the girl standing very close to you, singing her song quietly in your right ear". Our machine makes the miracle of recreating the past in a vivid way so that the emotions of that performance can be revived still in the present and every time you desire. With this recording, the engineer Phil Ramone won a Grammy award for the best sound. The recording was made on a tape that spun at the speed of thirty inches per second, exactly the double of the standard fifteen inches. In addition to the talent of the Getz/Gilberto duo, there is also the huge work of weaving and structuring that makes Milton Banana one of the greatest percussionist/drummers of the Bossa Nova of that epoch. The album is magnificent, as magnificent is the sound image that the GamuT gives back to us with immense lyricism and involving groove. Impressing is the way he exalts the differences between the two versions and how he reproduces both of them. The same happens with the piano resonance generated by the hammer that hit the metallic strings making vibrating the woods. The three-dimensionality is a reference because, also with a limited concentration, you can notice some light movements that the performers do and that show up with clear acoustic changes giving to the listener the tools to "see with the ears" and evaluate a dynamic/visual phenomenon through a support predisposed for the hearing. It is not an abstract concept.


Paul Hindemith, discoursing on music abstraction, affirmed that the ear should remain the first and last court of appeal. This is a concerned exhortation to listen.

With the GamuT D200i, which proposes itself as precious way to enter in harmony with music, it should be a pity not to accept the invitation.

 

 

Official technical specifications

Type: single mosfet, solid state power amplifier
Output power: 200W/8Ω, 400W/4Ω, 698W/2Ω
Frequency response: 5Hz-100kHz
Distortion: <0.05%
Noise: >100dBA below 100W/8Ω
Input impedance: 40kΩ balanced, 20kΩ RCA
Sensitivity: 0.77V, 1.55V, 3.1V, 3.9V, for full power
Loudspeaker load: up to 1.5Ω
Power Consumption: 100W
Dimensions: 44,70x15,50x43,18cm (WxHxD)
Weight: 34kg

Official Italian dealer: to Il Tempio Esoterico website

Official current price in Italy: 11,000 EUR

Associated equipment: to Giuseppe “MinGius” Trotto system

 

 

 

RIGHT OF REPLY | MANUFACTURERS FEEDBACK

Dear Giuseppe,
thank you for a comprehensive review of our D200i Stereo Power amplifier. We appreciate that we got the chance of having our amp being evaluated.
Actually the toroidal trafos is not only 500VA but 800 VA and the reserve on the output is 22Volt.
These are of course minor and does not at all affect the great and thorough review you have made and we look forward to be working with you on other products.

Best regards
Torben Sondergaard
Sales Manager GamuT

13/03/2013

by Giuseppe
Trotto
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