MARS TUBE AUDIO – MARS SET TUBE AMPLIFIER

The inspiration behind the design of the Mars SET is the discovery that music can be experienced satisfactorily, maybe even more deeply, at lower dB levels. It does imply the necessity/advantage of pairing high sensitivity speakers to the SET. Experience has shown that this issue is not clear cut. Some speakers with a sensitivity of below 94 dB/watt might sound great (and loud enough), while some sensitive speakers may not do the amplifier justice.

From our first experience with tube stereo amplifiers in the late nineties, single ended amplifiers have stood out for their clarity and high frequency resolution, and especially their smooth transition from linear to overdrive conditions. The fact that you only need two output tubes, as apposed to four or eight for push-pull amplifiers, to keep your SET running, is also appealing.

If you listen to music all day, you’ll notice that the audio levels needed for clear music is way below the rated power capacity of most amplifiers. This “The First Watt is the most important” philosophy is most apparent with Single Ended amplifiers, especially with triodes famed for their low distortion.

(https://www.psaudio.com/blogs/pauls-posts/first-watt?srsltid=AfmBOoqsxckePxrfwkWKQCCLCR0Bw_g0dzkhf0e7uHeWmH0WVgwK7wkA)

At these lower power levels, you gain an effortless music experience, and hours of listening does not induce listening fatigue.

The Mars SET amplifier is an integrated Single Ended Triode amplifier with about 8 watts per channel music power output. This might sound like a low power amplifier, but you have to experience the sonics of 8 watts of Class A triode power, to realise that this is a very powerful amplifier.

The bass response and general power capacity of the KT88, not to mention the plethora of options in current manufacture, makes it an ideal tube for a high power SET output stage. The cathodes are indirectly heated, which facilitates very low levels of noise/hum during operation. The well-designed power supply filter section, utilising capacitor-inductor-capacitor (CLC), allows a wide sound stage to be experienced.

The care in producing exactly similar output transformers (one pair manufactured at a time) and the well-designed power supply section are probably why. We also take care to construct the stereo amplifiers with exactly the same layout for Left and Right Channel.

The KT88s can be expected to last about 5000 hours, and the pre-amp tubes closer to 10 000 hours. The rectifier tube can be expected to last many years. Common wisdom suggests replacing the power tubes every second year, and pre-amp tubes every four years.

We manufacture our own transformers, allowing us the ability to go beyond what is available on the open market. Experimenting has shown that size matters a lot, and our designs can reproduce 20 Hz. The 114 mm sized laminations on a 50 mm stack we use on the output transformer, allows the wide bandwidth and low losses you need for dynamic music reproduction.

    • 8 watt per channel music output

    • 250 VA power transformer (power consumption is about 100 VA)

    • 25 watt output transformers with 7% local cathode feedback (24 Henry primary inductance)

    • Each output transformer have 9 sections inter-leafed for optimal high frequency response

    • 25 Kg weight; 420 mm wide, 370 mm deep and 250 mm high

    • 2 x Shuguang KT88 triode wired output tubes with cathode bias (any type of KT88 can be supplied on request)

    • Class A operation

    • NOS 5U4G tube rectifier

    • NOS 6SL7GT input tube (grounded cathode)

    • NOS 6BL7GT driver tube (cathode follower)

    • One capacitor in signal path: AV（ARCOTRONICS）0.47UF 850V MKP axial coupling film capacitor

    • Zero global feedback

    • Dual-mono power supply with separate PI filters for each channel

    • Polypropylene filter capacitors

    • Alps RK27 100Kohm stereo potentiometer

    • All resistors are carbon composition 2 watt types, except high power wirewounds used on cathodes and in power supply.

    • Cathode bypass capacitors are Low ESR audiophile grade electrolytics.

    • Point-to-point wiring

    • Silicon covered hookup wire used throughout (500V 180 degrees C).

    • Designed for loudspeakers from 4 to 8 ohm impedance.

    • Welded steel enclosure with black epoxy covering.

    • 6 month guarantee on tubes; 2 years on amplifier hardware and components.

    • Shipping worldwide can be arranged.

    • Production capacity: two amplifiers per month. 30 days to deliver from receiving order.