Miyajima Laboratory ETR-Mono

This ETR-MONO is a monaural stepup transformer.
The stereo sound source is changed to a monaural sound source.
If you use ETR-MONO by a monaural system, please use only one channel.

- The calking material is "paraffin"
- Highest grade core material, permalloy 80 for the core of the transformer is used.

I wanted to make the monaural stepup transformer for monaural cartridges.
However, the impedance of the monaural cartridge is low, and the output is high.
It was difficult to match it with the input impedance of the pre-amp.
I hit on a good idea.
It enables the design of the monaural stepup transformer to change the input impedance of the pre-amp.
In addition, I understood that this idea could regulate sound quality by the preference of the user.
 
ETR-MONO can regulate a gain.
And ETR-MONO can regulate impedance.
Therefore, ETR-MONO realizes ideal frequency balance.

Numerical value of the left switch is the number of the winding of the coil of the InputCoil.
Numerical value of a central switch is the number of the winding of the coil of the OutputCoil.
An amplification rate is the ratio of the number of the winding.
The right switch can change the input impedance of the pre-amp.

For example, a user chooses 120 of Input for a cartridge of 6 Ω and chooses 3000 of Output.
It is a gain of 25 times. (27.5dB)
The calculation methods of Impedance are as follows.
25 times x 25 times x cartridge 6 Ω = 3,750 Ω = 3.75kΩ

Therefore, I recommend impedance of 3.9kΩ.
However, the user can regulate these numerical value for the preference of the sound.
If a user likes gentle sounds, please lower the impedance.

Numerical value of the reference for the impedance of the cartridge.

InputCoil
80 = 2-5 Ω
120 = 6-12 Ω
160 = 12-20 Ω
200 = 20-40 Ω