hMiyajima ETR-STEREO Overview
Product Name: MC Stepup Transformer “ETR-STEREO”
Input Capacitance: 0.00 / 0.47 / 0.68 / 1.00 / 1.50 /2.20 μF
Input Impedance: 2 – 100 ohm (this is the cartridge coil impedance, not the transformer’s primary winding impedance)
Output Impedance: 3.6k – 47k ohm (47k = PASS)
Voltage Stepup Ratio: Approximately 11 – 40 dB (3.7 – 100 times)
Demagnetizer: Push button to demagnetize.
Dimensions: W150 x H70 x D175 mm
Weight: 1 kg
The transformers are wound around highest-quality permalloy 80 material, and filled with carnauba. The various controls give great adjustment of input impedance to match a wide range of MC cartridges, as well as gain. There is also the option of adding capacitance to the input, which can be useful to tame cartridges having a high frequency peak. The ‘impedance’ control applies secondary loading resistance and together with the other controls gives the user great control over the overall sound character.
About Input Capacitance
Most cartridges have a slight peak in the high frequency range, which can be reduced by applying an appropriate capacitance at the SUT input. Miyajima recommend that this value is best set by ear, while listening to music. When input capacitance is not necessary, set the control to 0.00μF.
Input and Output Coil Settings
Setting the input and output coils alters the effective impedance load seen by the cartridge, and the gain ratio. The input coil control should be set according to the nominal coil impedance of the cartridge, as follows:
Input Coil Cartridge Coil
80 2-5 Ω
120 5-12 Ω
180 12-30 Ω
270 30-100 Ω
The input and output coil settings are the number of turns in the primary and secondary windings, and not actual impedance. The coil values can be used easily to calculate the gain ratio, for example if you choose input coil setting of 180, and output 4000, the gain ratio is 4000/180 = 22.2 times.
You can keep the ETR-STEREO in circuit even when using a MM cartridge, in which case set both Input Coil, Output Coil and Impedance controls to ‘Pass’.
The back push button removes the magnetization of a cartridge and the stepup transformer. Please push this button for ten seconds while playing a record. While you push the button, the music stops.
The cartridge and transformer are demagnetized by the interchange signal of the LP and the overall sound is slightly cleared by demagnetizing it. Please use demagnetization every few months.
Because this demagnetization method does not add electricity, there is no risk to the cartridge.
ETR-STEREO can pick up induction hum by putting it near a power supply transformer or power supply cable. Please keep away ETR-STEREO from a power supply transformer and a power supply cable as much as possible. If hum occurs, move the SUT around to find a quiet position. Also, always use good quality, fully screened cables.
Read a customer review on the Art of Sound Forum here