Petr Žwak - tube amplifiers

Mars - MM phono tube preamplifier

Main page

	Used tubes	E88CC, 6F12P, ECC82 for each channel
	Optimal input	1.5 mV - 5 mV / 47 kOhm
	Optimal load	47 kOhm / 80 pF - 1000 pF selectable
	Gain	47 dB / 1 kHz
	THD distortion	max. 0.04% in the range 20 Hz - 20 kHz / 0.775 V
	Output voltage nom.	0.775 V / 1 kOhm / 1kHz (max +20 dB overload)
	Frequency range	20 Hz - 50 kHz (RIAA filter correction)
	Deviation from RIAA	max. +/- 0.2 dB
	S/N ratio 0 dB (A)	min. 78 dB
	Power supply	230 VAC / 30 W (0.5 W standby)
	Size (h x w x d)	90 x 135 x 240 mm (one box)

The preamplifier Mars for MM phono cartridge is designed from legendary tubes with sound quality in mind and meets even very high demands. It is equipped with selected passive and active components of high quality with regard to the durability of the device and the desired sound expression with the option of choosing alternative tubes. No semiconductor element is used in the audio path, only tubes.

The preamplifier uses two active stages in the Mu Follower topology, between which a passive RIAA filter is inserted. The first stage is equipped with a low-noise E88CC. The second stage uses a special triode / pentode topology 6F12P, which allows you to achieve high gain with low distortion. The White Cathode Follower ECC82 is used at the output, which, thanks to its low output resistance, enables optimal excitation of the next amplifier even with longer lines. The preamplifier has no global negative feedback (NFB), the tubes are paired. The MM cartridge load can be selected between 80 - 1000 pF. The preamplifier is designed in two separate cabinets to suppress source interference. The cabinets can have a silver or black front panel just like Jupiter. Both the preamplifier and the power supply (PSU) are controlled by a microprocessor to provide the highest optimal sequence / shutdown and thus ensure the life of the tube. The microprocessor also monitors the internal temperature of the preamplifier against overheating.