GamuT D3i preamplifier and D200i power amplifier
- Jason Kennedy
- Aug 2015
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.
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.
I kicked off the listening by using the D200i with the Townshend Allegri passive controller; this proved a nostalgic experience because despite the many changes to the amplifier and to my system since I last used a D200 the same character was evident – an effusive vivacity made possible by excellent dynamics and the authority of serious power reserves. This, however, is not a leaden muscle amp and it doesn’t sit on the music in the way that so many do; instead, it infuses the music with life and energy, giving orchestral works the vitality they require if they are to move you fully. The D200i has a slightly sparkly, bright sound compared with my regular ATC P1 power amp, and this quality requires a suitably calm, maybe even restrained loudspeaker to make a good match. The PMC fact.8s are very open and revealing, but not quite as good a choice as the Bowers 802Ds were. However, they do allow this amp to pull tons of space and ‘air’ out of recordings like Gregory Porter’s ‘No Love Dying’ [Liquid Spirit, Blue Note]. This seems a little crisper than usual, but you can also hear more detail so it’s hard to say whether the amp is revealing or adding it.
Chris Jones ‘Roadhouses & Automobiles’ [Roadhouses & Automobiles, Stockfisch] is a rather more polished recording and here you can appreciate the effects that have been used on his voice and those of the backing singers. In some respects the D200i has valve like characteristics with transistor style control. It doesn’t have the smoothness of a good valve amp but it has a lot more grip, albeit not in a way that gets between listener and music. It doesn’t, for instance, match my ATC P1 for low end extension and grip, but has a far more open and dynamic style, it delivers detail better than power but that serves the music extremely well.
Adding the D3i preamplifier to the mix opens out the soundstage even further. This is because the strict dual-mono preamp design yields extremely high channel separation, which in most cases results in a wide soundstage; consequently, the speakers should be toed inwards further, to create correct width. This will result in a soundstage with even more depth and precision. Depth of image is particularly good with Javier Perianes playing on Manuel Blasco de Nebra’s Piano Sonatas [Harmonia Mundi], while the reverb is massive and the richness of tone beguiling. Timing appears not as strong as it is with the Allegri, but a passive preamplifier will typically create a small phase shift depending on volume setting, so changing to a buffered preamplifier will actually result in a linear phase behaviour. The potential for high frequency attenuation in a passive preamplifier is a consideration, too.
Taken as a pair, the GamuT duo put on a fine show. ‘Goodbye Pork Pie Hat/Brush With The Blues’, from Jeff Beck’s Live at Ronnie Scott’s [Eagle Records] is not short on scale and has oodles of detail, which makes for a truly electric atmosphere that seems more than a small club like Ronnie’s could contain. What I really like, however, is the way that these amps focus on the playing more than the sound; this apparently obvious aim is not always achieved by high-powered amplifiers, but here the combination of light-handed control lets you hear all the elements in the mix in perfect balance.
The GamuT pair, especially the D200i, manage to combine power with tonal subtlety – a quality that serves whatever music you want to play very effectively. The D3i is not the most relaxed or natural-sounding preamplifier on the planet, but it can produce a vivid and entrancing sound that lets you hear the meaning in the music. It is extremely good at resolving reverb and timing, though not in the front league, is certainly not sluggish. With Barenboim’s Beethoven For All Symphony No.1 in C, Op.21 [24/96, Decca], the orchestra really breathes (again!): it’s too big for the room, but you get a strong sense of the power and dynamics on tap. Some might want a bit more authority – essentially more power in the bass – but that is very difficult to achieve without undermining musical flow, something at which the GamuT pair excel. Stiffer power amps give a Beethoven symphony gravitas, but if you are after the joy alongside the ‘Sturm und Drang’ the GamuT have the upper hand.
The GamuT D200i retains the combination of musicality and power that kept me listening long into the night. It is more transparent than before and, when partnered with the D3i, makes for amplification that put music under its spell. Those looking to shake the furniture may have to look elsewhere, but anyone who wants to be spirited away should lend GamuT an ear.
- Type: J-FET NPN line-stage preamplifier
- Analogue inputs: Four pairs of single-ended inputs (via RCA jacks), one pair of balanced inputs (via XLR)
- Analogue outputs: Two pairs of balanced outputs (via XLR connectors), one pair of single-ended outputs (via RCA jacks), one pair of single-ended Tape Outputs (via RCA jacks)
- Input impedance: 20kOhms single ended
- Output impedance: 75 Ohms single ended
- Bandwidth: 5Hz-100kHz
- Gain: 5dB
- Distortion THD+N: < 0.0008% (/2Vrns)
- Signal to Noise Ratio: 110dBA
- Dimensions (HxWxD): 108 × 430 × 410mm
- Weight: 12kg (packed)
- Price: £5,499
- GamuT D200i
- Type: Single pair NPN MOSFET output device transistor power amplifier
- Analogue inputs: One pair balanced (via XLR connectors), One pair single ended (via RCA jacks)
- Analogue outputs: Two pairs of speaker taps (via 5‑way binding posts)
- Power output: 2x 220 Wpc into 8 Ohms, 2x 400 Wpc into 4 Ohms, 2x 700 Wpc into 2 Ohms
- Bandwidth: 5Hz-100kHz
- Dimensions (HxWxD): 155 x 430 x 390mm
- Weight: 34kg
- Price: £9,299
Manufacturer: Gamut A/S
UK Distributor: Sound Fowndations
Tel: +44(0)118 981 4238
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