I have some history with the GamuT D200 power amplifier; the original version was my reference amplifier for many years and powered at least two generations of Bowers & Wilkins 802 Diamond speakers. I liked it a lot, but somewhere along the upgrade path to MkIII status, it began gathering dust and I let it go. Hearing the latest D200i brought back what I loved about this Danish beast.
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GamuT D200i Dual-Mono Amplifier. Need a manual for your GamuT D200i Dual-Mono Amplifier? Below you can view and download the PDF manual for free. There are also frequently asked questions, a product rating and feedback from users to enable you to optimally use your product. If this is not the manual you want, please contact us. GamuT CD player. Noise levels will be lower. We use switches, because they can be set precisely identical and will preserve the stereo balance. The maximum voltage gain of GamuT D200 MkIII is 35dB, and the GamuT C100, D100, M200 and M250 also have 35 dB maximum gain, so they will all work together in a. Hi, I'm selling my Gamut D200mk3 power amp which is in immaculate condition and complete with manual and original double box. Bought from Rochester Hifi as demo in 2007 and has provided fantastic service since then. Looking for £2,200 cash on collection or if buyer wants it shipped it will be £2,300 via PayPal with buyer paying for shipping.
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- GamuT CD player. Noise levels will be lower. We use switches, because they can be set precisely identical and will preserve the stereo balance. The maximum voltage gain of GamuT D200 MkIII is 35dB, and the GamuT C100, D100, M200 and M250 also have 35 dB maximum gain, so they will all work together in a bi-amped system.
GamuT makes two power amplifiers, of which this is the stereo option. The M250i is an even more powerful monoblock, but the as the name suggests, the D200i's delivers a healthy 200W in its own right. GamuT amplifiers use a single high-current MOSFET output transistor per channel, where most other solid state amplifiers use multiple output devices and if these differ in their electrical characteristics, distortion creeps in. Manufacturers therefore tolerance their output devices as tightly as possible; Naim takes this to its logical extreme with its Statement amps, where each set of output transistors are made from adjacent pieces of silicon from the same die – but that is clearly a pricey approach.
The reason that solid state amps have multiple output devices is because this gives more power and more power needs more heat dissipation. So how does GamuT get away with using only one device? I asked engineer Benno Baun Meldgaard this question and he explained that they use industrial transistors that were developed for motor control and welding, and are even able to handle 400 amp peaks. This type of transistor is not available in the usual complimentary positive and negative pairs (PNP and NPN), but just NPN or ‘negative' and GamuT had to do a lot of work to stabilise two of these devices for each channel, effectively turning them into a pair. To Benno's knowledge, Constellation Audio is the only other company that does this and then with multiple pairs rather than one.
The latest D200i now has a single emitter resistor network, which consists of three paralleled 0.12ohm resistors, creating a combined resistance of 0.04ohms. That is about 5-10x lower than most amps. The transistors themselves are of higher quality and the power supply has been reconfigured with better parts and a quieter transformer than before. Rectification is now balanced and has twice the capacity, in the process halving resistance and lowering noise. Finally, the internal cabling has been changed to GamuT's Wormhole speaker cable, an unusually thin type for a high power amp maker.
GamuT only makes one preamplifier: the D3i. This is described as a dual-mono design and has both balanced and single ended inputs and outputs on its substantial yet not overly weighty carcass. One pair of the RCA phono inputs is marked RIAA with a matching legend on the backlit front panel. However, as things stand it does not connect to a GamuT phono stage, which is still in development but should be available by the end of the year. At present, this input functions as a balanced input on RCA sockets; it works with an XLR to RCA cable, wired positive to centre pin and negative to the collar, plus a flying earth lead screwed under the ground connector. This configuration can also be used with any balanced line level input. The HTH/home theatre input can be used in bypass mode for combined stereo and multichannel systems.
January 2003
GamuT D-200 Stereo Power Amplifier
Review By Rufus Smith
Click here to e-mail reviewer
Danish designer Ole Lund Christianson's Gamut D-200 amplifier differs from its competitors in the high power sweepstakes in its use of a single high power MOSFET to produce its rated power. Previously, most high power amplifiers made use of multiple transistors operated in a parallel fashion to produce their rated power. The major drawback to this design philosophy is that no matter how hard you try; you are never able to completely match the transistors. As a result the signal that is produced is a mixture of the signals from all the parallel-coupled transistors. According toGamuT, the result is that the fine details found in music can be lost.
The MOSFET used in the D-200 was originally for use in switch-mode power supplies and is capable of handling more than 500 watts and passing a peak current of more than 300A. The stereo D-200 utilizes two of these single MOSFETs per channel, one on the positive rail and one on the negative rail. A push-pull amplifier operating in Class A drives each output device. This amplifier has the ability to charge the gate either up or down. The driver stage has a voltage source 15V higher than the output device voltage rail to help control the MOSFET when it is approaching its maximum output. The power source for the D-200 is two 500VA toroidal transformers with32,000 µF of capacitance.
Due to the high current capability of the MOSFETs, GamuT designed a sophisticated protection circuit for the D-200. Through the use of both thermal and current sensors, the circuit detects DC errors, high-level subsonic signals, long-term ultrasonic signals, high temperature, low impedance loads and short circuits. In addition, the circuit monitors the voltage, current and phase of the load being presented to the amplifier. If any of these conditions are detected, the protection will simply mute the input signal or if necessary, open the output relay.GamuT has designed the relay to open only after the input has been muted to prevent the contacts of the relay from being damaged by switching current as the relay reacts to the situation.
In Practice
Okay, so how does it work? Say for instance the circuit detects a short. The protection circuit will immediately mute the input for about a second and the output relays will then open. The circuit then sends out a 1-millisecond long pulse to test the circuit. If the condition is still present, the protection circuit remains engaged. As soon as the circuit determines the problem has been corrected, the system automatically resets itself and the music begins playing.
The protection circuit precludes the D-200's use with loudspeakers who have an impedance of less than 2 Ohms.GamuT has set the protection circuit so that the amplifier will deliver its full output into loads greater than 1.5ohm. Should the amplifier's protection circuit detect an impedance load lower than 1.5ohm, the circuit will alert you by muting the input for a second. In most real world situations, this should not be a problem.
The D-200 measures a diminutive 17 inches wide, 18 inches deep and 6 inches high and weighs a gut-wrenching 68 pounds. The review sample was finished in the traditionalGamuT black livery with the optional chromed faceplate. The faceplate has a center mounted power switch with a single green LED to indicate that the unit is powered up. The chassis is made ofstainless steel while the front panel and heat sinks are sanded three times to obtain a very smooth surface. The rear panel is nicely laid out. There are provisions for both unbalanced and balanced operation by way of the traditional RCA and XLR connections. If you decide to use the amplifier unbalanced, remember to insert the supplied shorting plugs tying pin 1 and 3 together.
Loudspeaker connection is by way of two sets of beefy WBT connectors. One pair of the connectors is a direct connection, which bypasses the filter network that protects most amplifiers against capacitive speaker and cable loads. According to Christensen, the using the direct connection increases the fidelity of the sound particularly in the upper registers.Also, he says the only difference between Direct and Normal output is the coil/resistor network for electrostatic loudspeakers,both are protected for shorts. If you bi-wire your speakers, Gamut recommends using the filtered connectors for the bass and the direct connections for your midrange/treble connections. If electrostatics are your thing, reverse the above convention. Please be warned, if you use the direct connection, make absolutely sure that you do not short the connections, as there is no guarantee that the amp will survive. Thankfully this is extremely hard to do as the Gamut uses European specification WBT's that are completely encased in plastic. There is also one small negative associated with these connectors. Certain cables may not fit the posts due to the small opening in the plastic sheath through which they must be inserted.
- Motorcycle Manuals, carl salter, Website about motorbikes. Free Motorcycle Manuals for download. Lots of people charge for motorcycle service and workshop manuals online which is a bit cheeky I reckon as they are freely available all over the internet. £5 each online or download them in PDF format for free here!!
- GamuT CD player. Noise levels will be lower. We use switches, because they can be set precisely identical and will preserve the stereo balance. The maximum voltage gain of GamuT D200 MkIII is 35dB, and the GamuT C100, D100, M200 and M250 also have 35 dB maximum gain, so they will all work together in a bi-amped system.
GamuT makes two power amplifiers, of which this is the stereo option. The M250i is an even more powerful monoblock, but the as the name suggests, the D200i's delivers a healthy 200W in its own right. GamuT amplifiers use a single high-current MOSFET output transistor per channel, where most other solid state amplifiers use multiple output devices and if these differ in their electrical characteristics, distortion creeps in. Manufacturers therefore tolerance their output devices as tightly as possible; Naim takes this to its logical extreme with its Statement amps, where each set of output transistors are made from adjacent pieces of silicon from the same die – but that is clearly a pricey approach.
The reason that solid state amps have multiple output devices is because this gives more power and more power needs more heat dissipation. So how does GamuT get away with using only one device? I asked engineer Benno Baun Meldgaard this question and he explained that they use industrial transistors that were developed for motor control and welding, and are even able to handle 400 amp peaks. This type of transistor is not available in the usual complimentary positive and negative pairs (PNP and NPN), but just NPN or ‘negative' and GamuT had to do a lot of work to stabilise two of these devices for each channel, effectively turning them into a pair. To Benno's knowledge, Constellation Audio is the only other company that does this and then with multiple pairs rather than one.
The latest D200i now has a single emitter resistor network, which consists of three paralleled 0.12ohm resistors, creating a combined resistance of 0.04ohms. That is about 5-10x lower than most amps. The transistors themselves are of higher quality and the power supply has been reconfigured with better parts and a quieter transformer than before. Rectification is now balanced and has twice the capacity, in the process halving resistance and lowering noise. Finally, the internal cabling has been changed to GamuT's Wormhole speaker cable, an unusually thin type for a high power amp maker.
GamuT only makes one preamplifier: the D3i. This is described as a dual-mono design and has both balanced and single ended inputs and outputs on its substantial yet not overly weighty carcass. One pair of the RCA phono inputs is marked RIAA with a matching legend on the backlit front panel. However, as things stand it does not connect to a GamuT phono stage, which is still in development but should be available by the end of the year. At present, this input functions as a balanced input on RCA sockets; it works with an XLR to RCA cable, wired positive to centre pin and negative to the collar, plus a flying earth lead screwed under the ground connector. This configuration can also be used with any balanced line level input. The HTH/home theatre input can be used in bypass mode for combined stereo and multichannel systems.
January 2003
GamuT D-200 Stereo Power Amplifier
Review By Rufus Smith
Click here to e-mail reviewer
Danish designer Ole Lund Christianson's Gamut D-200 amplifier differs from its competitors in the high power sweepstakes in its use of a single high power MOSFET to produce its rated power. Previously, most high power amplifiers made use of multiple transistors operated in a parallel fashion to produce their rated power. The major drawback to this design philosophy is that no matter how hard you try; you are never able to completely match the transistors. As a result the signal that is produced is a mixture of the signals from all the parallel-coupled transistors. According toGamuT, the result is that the fine details found in music can be lost.
The MOSFET used in the D-200 was originally for use in switch-mode power supplies and is capable of handling more than 500 watts and passing a peak current of more than 300A. The stereo D-200 utilizes two of these single MOSFETs per channel, one on the positive rail and one on the negative rail. A push-pull amplifier operating in Class A drives each output device. This amplifier has the ability to charge the gate either up or down. The driver stage has a voltage source 15V higher than the output device voltage rail to help control the MOSFET when it is approaching its maximum output. The power source for the D-200 is two 500VA toroidal transformers with32,000 µF of capacitance.
Due to the high current capability of the MOSFETs, GamuT designed a sophisticated protection circuit for the D-200. Through the use of both thermal and current sensors, the circuit detects DC errors, high-level subsonic signals, long-term ultrasonic signals, high temperature, low impedance loads and short circuits. In addition, the circuit monitors the voltage, current and phase of the load being presented to the amplifier. If any of these conditions are detected, the protection will simply mute the input signal or if necessary, open the output relay.GamuT has designed the relay to open only after the input has been muted to prevent the contacts of the relay from being damaged by switching current as the relay reacts to the situation.
In Practice
Okay, so how does it work? Say for instance the circuit detects a short. The protection circuit will immediately mute the input for about a second and the output relays will then open. The circuit then sends out a 1-millisecond long pulse to test the circuit. If the condition is still present, the protection circuit remains engaged. As soon as the circuit determines the problem has been corrected, the system automatically resets itself and the music begins playing.
The protection circuit precludes the D-200's use with loudspeakers who have an impedance of less than 2 Ohms.GamuT has set the protection circuit so that the amplifier will deliver its full output into loads greater than 1.5ohm. Should the amplifier's protection circuit detect an impedance load lower than 1.5ohm, the circuit will alert you by muting the input for a second. In most real world situations, this should not be a problem.
The D-200 measures a diminutive 17 inches wide, 18 inches deep and 6 inches high and weighs a gut-wrenching 68 pounds. The review sample was finished in the traditionalGamuT black livery with the optional chromed faceplate. The faceplate has a center mounted power switch with a single green LED to indicate that the unit is powered up. The chassis is made ofstainless steel while the front panel and heat sinks are sanded three times to obtain a very smooth surface. The rear panel is nicely laid out. There are provisions for both unbalanced and balanced operation by way of the traditional RCA and XLR connections. If you decide to use the amplifier unbalanced, remember to insert the supplied shorting plugs tying pin 1 and 3 together.
Loudspeaker connection is by way of two sets of beefy WBT connectors. One pair of the connectors is a direct connection, which bypasses the filter network that protects most amplifiers against capacitive speaker and cable loads. According to Christensen, the using the direct connection increases the fidelity of the sound particularly in the upper registers.Also, he says the only difference between Direct and Normal output is the coil/resistor network for electrostatic loudspeakers,both are protected for shorts. If you bi-wire your speakers, Gamut recommends using the filtered connectors for the bass and the direct connections for your midrange/treble connections. If electrostatics are your thing, reverse the above convention. Please be warned, if you use the direct connection, make absolutely sure that you do not short the connections, as there is no guarantee that the amp will survive. Thankfully this is extremely hard to do as the Gamut uses European specification WBT's that are completely encased in plastic. There is also one small negative associated with these connectors. Certain cables may not fit the posts due to the small opening in the plastic sheath through which they must be inserted.
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Sounding Off
The D-200 replaced my reference Pass Labs Aleph 1.2 monoblocks on the twin towers of the Nearfield Acoustics Performance 924 loudspeakers. TheGamuT drove the 924's full range with all but the lowest octave handled by the superb REL Stadium III subwoofer, which was crossed over to the towers at 32Hz. The D-200 that I received came to me directly from CES so it was pretty well broken in when I received it therefore I cannot give you much insight into the unit as it goes through the break-in process. In any case, I let it play non-stop for 72 hours before I sat down to do any critical listening. During this 72-hour period, the sound of the unit changed very little from when it was first inserted into the system.
The first thing that grabbed my attention about this amplifier was the quality of its soundstage, which is among the very best I have ever heard. The sense of depth produced by this diminutive amplifier rivals some of the best tube amplifiers out there. On orchestral recordings, the rows of instruments were very nicely layered with the proper amount of separation between them. Lateral placement of the instruments within the soundstage was equally precise. John Rutter's Requiem (Reference Recordings, RR57) as performed by the Turtle Creek Chorale and the Women's Chorus of Dallas really showcases the superb soundstaging capabilities of this amplifier. The Morton H. Meyerson Symphony Center that the Chorale and Chorus call home is fast earning a reputation as being one of the best halls in the country. My favorite cut from this album is 'PieJesu', which features soprano Nancy Keith. As Ms. Keith performs, the entire chorus swells up behind her filling the hall with glorious sound that will almost bring tears to your eyes.
The D-200 is remarkably clean and coherent from top to bottom. Transients are cleanly produced and march along in perfect lockstep with the harmonics, which gives the music an excellent sense of drive. Music seemed to flow from speakers with a sense of ease. This amplifier is also very low in distortion. This allows low-level details to flow out of a seemingly endless black hole. This black background allowed silent passages to seem even darker, which gave even greater impact and power to each note played. The 'Absolute Sound's' CD Hearts of Space really is an excellent test CD. While it is not the type of music I would listen to everyday, it has become a valuable tool in my reviewing process. Track 8'Sama' is an excellent test of your systems ability to reproduce depth. The beginning of the cut features scrapped rocks and other sounds that seem to well up out of the depths. To hear these sounds at their lowest level requires a system capable of very high resolution. Many amplifiers that I have used in this system mask the first few notes of this track. TheGamuT's noise floor is low enough that it does not seem to get in the way and cover up those wonderful low-level details.
The GamuT seems remarkably balanced from top to bottom. It does not seem to favor one part of the music spectrum over another. Low-level bass extension and dynamics are very good. My Pass Labs Aleph 1.2 monoblocks are not known for their superb bottom end performance. However, I find their bass performance to be exceptionally good. I place the Gamut in the same camp. Neither amplifier generates the same deep bass energy as say, one of the more expensiveKrells. This may make the D-200 seem like it is missing measure of dynamics. I can assure you itis not. 'Black Magic Woman' from Patricia Barber's Companion (Blue Note, 7243 5 22963 2 3) features a superb drum solo by EricMontzka. Montzka's drum kit was presented accurately. The same could be said from Michael Arnopol's bass. There was none of the thick turgid mess that generally passes today for excellent bass performance.
Moving up through midbass all the way through the midrange, the D-200 remained crisp and very nicely detailed. Textures remained true to the original. It was in this area though that the D-200 gave up a little ground to my reference Pass Aleph 1.2 monoblocks. The Aleph is known for the quality of its midrange, which is very dimensional and harmonically rich. The Gamut's midrange, on the other hand, had an immediacy, airiness and clarity that created a sense of intimacy that was a pleasure to listen to. However, the slight lack of harmonic richness that I am used to with the Pass amps did take just a little bit off my listening pleasure.
This is particularly noticeable on female voices. My friend, Beth Chorneau has just released a new album, which was recorded live at a new club in Charlotte called the EveningMuse. The acoustics are absolutely wonderful! The album called Stage Presence, Live At The EveningMuse (available from Pamona Records at www.jimbrock.net) features Beth Chorneau on vocals, Van Sachs on guitar, Gerard Benson on bass and Jim Brock on percussion. Beth's voice has asmokey, sexy quality to it that has to be heard to be believed. This album comes the closest to of any album I have heard of hers to capturing the true sound of her voice. When reproducing her voice, the Gamut tends to smooth out some of the huskiness that gives her voice so much character. The Pass provides a slightly better recreation of her voice by its very nature of being more harmonically rich. There was nothing really wrong about the way it presented her voice; it was just a little lighter than I am used to. Pleasedo not get me wrong, this is not meant to be a major criticism of the D-200, it is more of a nit-pick.
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The top octaves are reproduced with all of the energy, air, life and detail that any music lover could ever want. There was no edge or hardness to upper frequencies that could ever be considered harmful to the musical truth. The amplifier also exhibits explosive speed and overall dynamics. Music seems to flow from this amplifier with a sense of ease as long as it is not driven hard. This leads me to my major criticism of thisstereo amplifier.
The Finale
Gamut D200 Service Manual Online
If the D-200 has a weakness, it is that it seems to have less power than most similarly rated amplifiers. As the amplifier's power supply is used up and it is driven into clipping, the sound becomes brighter and edgier. The soundstage begins to collapse and the superb focus within the soundstage is lost. This is an amplifier that is best partnered with speakers that offer higher sensitivity. Speakers that offer lower sensitivity or electrostatics with wild impedance curves need not apply. For those speakers, Gamut offers the M-250 monoblocks or the exquisite S-300, at a much higher cost.
Gamut D200 Service Manual User
When used within its operating limits and partnered with speakers of moderate to high sensitivity, the D-200 is a true world-class amplifier that offers its owner a touch of sonic heaven at a real world price. My hat is off to Ole Lund Christensen for offering us mere mortals touch of sonic heaven. Highly recommended.
