I have been using this Martensen MPS phono preamp, with separate power supply, while my regular phono preamp was in for repair. It is an exceptionally good unit, although relatively unknown (the only review I could find was from HiFiPlus, and I will include that issue along with the unit).
What is not highlighted in the review, and what distinguishes this phono preamp from others of the time, is that it is a current domain amplifier, like the BMC and CH Precision currently being sold and which are the subject of rave reviews from users and critics. I verified that it is a current domain design by inserting resistors into the appropriate sockets, and when the resistance was lowered the volume went up--it was more noticeable with my Mutech Habyusa cartridge than with the Miyajima Kansui, which makes sense, as the Mutech has a very low source impedance.
What is also not commonly known is that this unit is essentially the same as the unit Clearaudio used to sell as its Reference. I suspected this after seeing a photo of the Clearaudio (see below)--it is obvious that it is almost the same as the MPS, and I confirmed this with Clearaudio. Thus, although there are no instructions for the Martensen available anywhere (and none are needed because their is no cartridge "loading" as is the norm with voltage domain designs), the instructions for the Clearaudio, a print out of which I will include, are helpful.
To my ears, this unit is extremely resolving, very dynamic, utterly quiet (when properly grounded) and of course trouble free.--probably as good a solid state unit as I can recall (I've owned Klyne, the Groove, VSE JLTI, among others, but didn't do a direct comparison to these as they were long gone) I would say that it is probably not as harmonically rich as a great tube unit, but that may be speaker and system dependent.
Please see the description below from other advertisements.
Description (taken from other ads):
The Martensen MPS phono stage was made in very small quantities by Lawrence Martensen during the years 2000 and 2005. It represents German-made craftsmanship at its best, and was imported by Audio Advancements during those years. Martensen has been a close associate of Willi Bauer, creator of the well-known DPS turntable, for which Martensen made a gorgeous power supply driving Willi’s 3-phase turntable motor, styled almost identical to the power supply of his MPS phono stage. The phono stage consists of three parts: the actual RIAA stage, the power supply and the umbilical cord. It is made to be used with low output cartridges, both MC and VR, and is based on a current-domain design, obviating the need for cartridge loading.
Moving Coil Phono Stage by Martensen, designer of power supply for the original Willi Bauer DPS turntable in Germany. Solid-State Current Mode Technology enables optimal performance independent of cartridge load/impedance - no matching required, just plug in and enjoy. Works with any MC cartridge with 0.3mV or greater output. Gain about 66dB. WBT RCA jacks, inputs and outputs on lower row, upper jacks marked "gain" can be used with loading plugs to lower overall gain, but I have never used them. About 10 years old. Comes with dedicated umbilical cord for power supply. Power supply can be converted to 230V 50Hz operation - I know this because the USA dealer (Audio Advancements, Branchville, NJ) has adjusted this unit for 120V 60Hz AC, and knows how to change it.
The unit has been totally reliable and has had no repairs or modifications.
Local pick up is welcome--otherwise buyer should expect to pay purchase fees and for shipping.