Bought new from AK Audio Labs. They are located in Brooklyn, NY. I used this successfully with two great low-output MC cartridges, the Shelter 5000 and the Zyx R-1000 Airy. Dynamic sense and detail increases nicely with this step-up, with considerably decreased background noise. My setup has recently changed, hence the sale. Nice thick aluminum box. Hi output switch is for >15 Ohm OR >0.4mV. It has a ground connection as well. There are several favorable reviews of their stepups, from Audio Karma, Dagogo, etc. Local pick up from Portland, Oregon is also welcome. From the manufacturers online ads:
T-20 Transformers are using Nickle Core and 99.9999% copper wire finished, and potted in the can for the best result. New designed Solid Aluminum chassis. Both of transformers installed in a 13cm (W)x15cm (H)x 20cm (D) case.
"HI" is for impedance(3--15 OHM), or output (0.2mV--0.4mV) MC cartridge.
"LO" is for impedance >15 OHM), or output>0.4 mV MC cartridge.
•Power ratio: 1:20 (About 20dB gain, depending on the impedance on the input and output loading)
•Transformer designed: 1+1:10+10
•Input impedance: >3 ohm – 40 ohm
•Output impedance: 47K ohm
•Channel balance: ＜0.5dB
•Frequency: 10Hz-85kHz (-1dB)