Particular attention has been paid to customer requirements that have not yet been realized in passive audio transformers available on the market, such as a variable MC terminating impedance or switchable ground connections.
Based on two high-quality 1:9 audio transformers from the company "Werkstätte für Studiotechnik, Dipl. Ing. Helmut Haufe GmbH & Co. KG", according to an original KLEIN+HUMMEL design specification this Step-Up transformer was developed, which is featured by the highest dynamic level with lowest distortions and high common-mode rejection ratio.
Due to theinput impedance of 570 ohms (*) without applied matching, the Step-Up Transformer is specially recommended for medium MC systems with an output voltage of around 1 mV, which are overdamped when connected to a real 100 Ohm MC input underdamped with very low resulting level when connected to a 47 kOhm MM input.
And for all Low Output MC systems, the input impedance of 15...350 Ohm (*) can be stepples adjusted to achieve the optimum sound - without any additional noise, and this can only be archived with active pre-pre amplifier stages by a high technical and financial effort!
Especially the absence of any additional noise is a knock-down argument to upgrade an already existing good MM pre-amplifier stage with this passive step-up transformer for the use with MC systems.
Also unique is the fact that the transformer's ground-free floating input and output can be configured to different ground connections by slide switches to completely eliminate any residual hum.
A Zobel combination and coupling resistors at the MM Pre-Amp connection (Vishay/Dale audiograde resistors and WIMA capacitors with 2.5% tolerance) do not only linearize the frequency response, but also avoid the oscillation that can occur with some sensitive MM phono preamps.
The black anodized aluminium housing and the honeycomb structure of the ground plane on the printed circuit board, which effectively suppress RF interference, as well as the MUNDORF SilverGold lead-free solder, which is used, should be mentioned almost unnecessarily.
The Step-Up Transformer can be completed within one hour without any soldering skills and can be setup for its audiophile purpose.
(*) When connected to a regulare MM phono input with 47 kOhms and 100 pF input-inpedance/ -capacitance and 130 pF interconnect capacitance (eg. Pro-Ject Connect it E).
Switchable connectivity options