Miyajima Components

MC Stepup Transformer “ETR-STEREO”

— Good point !! —
ETR-STEREO can add capacitance to input.
ETR-STEREO can choose appropriate input impedance for a cartridge.
ETR-STEREO can choose the amplification rate with four phases.
ETR-STEREO can choose appropriate output impedance for a phonostage.

The material of the core of the transformer is highest-quality permalloy 80.
Filling materials are carnauba.
Because ETR-STEREO can choose input capacitance and input impedance and an amplification rate and output impedance, I can get ideal frequency balance by various systems.
We achieved the impedance matching that had difficulty in stepup transformer by letting ETR-STEREO change the input impedance of the phonostage.
The user can look for ideal sound quality.
Probably the stepup transformer which can set capacitance and impedance freely is the world’s first thing.

1) About input capacitance
Most cartridges have a slight peak in the high frequency range.
When ETR-STEREO received an input signal with appropriate capacitance, it decreases a peak.
Please look for the most suitable numerical value while listening to music.
Slight noise to come out at the time of a capacitance change does not have any problem.
When MM cartridge and capacitance are unnecessary, please choose 0.00μF.

2) About the usage of the front coil switch
Numerical value of InputCoil and OutputCoil is winding amount of the coils. 
Please choose the winding amount of InputCoil suitable for the impedance of the cartridge.

Input Coil
80 = 2-5 Ω
120 = 5-12 Ω
180 = 12-30 Ω
270 = 30-100 Ω

Numerical value of the output coil is winding amount of the coils.
Please choose the appropriate numerical value to decide an amplification rate.
For example, it is the amplification of 22.2 times when a user chooses Input180 Output4000 for a cartridge of 16 Ω.
The output impedance switch changes the impedance of the phonostage.
The calculation methods of Impedance are as follows.

22.2 times x 22.2 times x cartridge 16 Ω = 7,885 Ω = 7.885 kΩ

Therefore, please choose the impedance from 8k ohm to 47k ohm.

In the case of MM cartridge, please choose PASS as both InputCoil and OutputCoil.
In addition, please choose 47kΩ(PASS) as Impedance basically.

3) About back DEMAGNETIZER switch
The back push button removes the magnetization of a cartridge and the stepup transformer.
Please push this button for ten seconds while listening to LP music. While you push the button, the music stops.
A cartridge and a transformer are demagnetized by the interchange signal of the LP.
A sound is slightly cleared by demagnetizing it. Please use demagnetization every several months.
Because this demagnetization method does not add electricity, the cartridge is safe.

4) About induction hum by the setting place of the transformer
ETR-STEREO causes induction hum by putting it near a power supply transformer and a power supply cable.
Please keep away ETR-STEREO from a power supply transformer and a power supply cable as much as possible.
While Induction hum occurs, please move a place of ETR-STEREO.
Because Induction hum increases and decreases, please look for the place where induction hum is the smallest.
In addition, the cable lacking in shielding causes induction hum. Please use a shielded cable.

MC Stepup Transformer “ETR-KSW”

This stepup transformer “KSW” was produced exclusively for Kansui,Shilabe,Waza.
It is the stepup transformer which is ideal for a stereo cartridge of Miyajima-Lab.
KSW removed the extra functions such as selectors to improve sound quality.

– KSW is installed in a beautiful TEAK case.
– The calking material is “paraffin”
– Highest grade core material, permalloy 80 for the core of the transformer is used. 
– The front button is a demagnetization function.

Demagnetizer
The DEMAGNETIZER switch removes the magnetization of a cartridge and the stepup transformer.
Please push this button for ten seconds while listening to LP music. While you push the button, the music stops.
A cartridge and a transformer are demagnetized by the interchange signal of the LP.
A sound is slightly cleared by demagnetizing it. Please use demagnetization every several months.
Because this demagnetization method does not add electricity, the cartridge is safe.

MC Stepup Transformer “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.

This is an image of the front panel of the monaural stepup transformer.

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

I produce an amplifier more than 30 years, and it meets a Japanese safety standard.
However, we cannot easily export amplifiers because an electric safety standard is in each country.
We need time for the acquisition of the CE mark.
We can sell a product to Japan and the United States now.

Vacuum tube pre-amplifier EC-5

I considered the usability of the front panel.  The circuit of this pre-amp is thought about for an LP.
It is easy to understand the row of terminals. The terminal is gold-plated.
Weight：about 8.5 kg　 Size：about H110 x W430 x D310 mm（including the terminal） Vacuum tube：2x 12AX7(5751)、3x 12AU7(6189) About a chassis ： The front and back are aluminum hairlines. Both sides are hammer ton. The top and bottom is a metal plate of the black painting. All the characters are carved characters. ＊The product of Miyajima-Lab may change the design without a notice.
The phonoinput of 3 circuits supports plural players. About an upper switch, the change of RIAA curve and the 78rpm curve is possible. The LP which is not RIAA of Colombian blue label / Victor LM series /etc of the initial LP recommends a position of 78rpm. The input impedance of A is standard 47kΩ. B and C can change impedance freely each.
The right photograph is a changeover switch of the input impedance of B and C. B : 600～47kΩ　C : 600～100kΩ An impedance matching improves by matching the impedance of the pre-amp to the impedance of a cartridge and the stepup transformer. When impedance is unclear, please choose 47kΩ.
	This is the volume and a switch. The materials of all knobs are aluminum.
The MODE switch is convenient. There are the output of the single channel and the output of the LR reverse. – 10dB is one-third of normal volume. – 26dB is 1/21 of the normal volume. The gain adjustment can fine-tune the volume and is useful as a mute switch.
	Please change the input of 6 circuits by SELECTOR. PHONO is divided into 3 circuits more by PHONO SW.
The input of 5 circuits except Phono is convenient.
	Please use DIRECT of OUTPUT for normal power amp. Please use VOLUME OUTPUT for the power amp of the high gain. The user is not troubled with the difference in gain of the power amp by controlling a gain by the subvolume.
This is REC terminal. The user can record a sound source without volume relations directly.
This pre-amp wires signal system with a single wire. The power supply-related cable is far from the signal system. In addition, this pre-amp secures enough voltage by a chalk transformer effectively. I was able to isolate correspondence from the noise of the power supply enough by easy space. The sound quality has transparency / strength / stability. This pre-amp drives various power amp by a mode switch ideally.

The photograph is the inside of Wo-1.
The vacuum tube of the equalizer is
EF86 and 6BX7-1/2.
The volume circuit is 12AU7 and 6SN7.
The Output circuit is 6BX7-1/2.
Wo-1 uses a big power supply transformer
and four chalk transformers.

This is a simple image of the volume circuit.
Wo-1 does not use a partial pressure by the resistance.

* What is NFB? (The complete explanation will be long, so I will briefly explain the NFB here)
It is a circuit that cancels distortion and noise by feeding back a signal opposite to the circuit.
Distortion and noise are eliminated, the frequency characteristics are greatly extended, and it can be shown to a very excellent amplifier on the data.
In general amplifiers, NFB is used favorably, but when used with a large numerical value, the sound quality obviously deteriorates.
To design a real amp, you need high technology and expensive parts that do not depend on NFB.

I made up my mind.
“Make an equalizer amplifier that does not distort even without NFB”
I think that adding NFB to a distortion-free amplifier has no problem, but I thought that even if NFB was added strongly to a distorted amplifier, good sound would not come out.
However, considering common sense, there is a limit to increasing permissible input by all means.
The answer that arrived at the end of trial and error is to change the equalizer circuit to a circuit like a power amplifier.
I chose a vacuum tube that I never used in preamplifiers and I changed the impossible to possible.
The completed preamplifier did not distort even if it exceeded 100 mV.
After that, I added the necessary NFB.
And an equalizer amplifier with an allowable input of 2000 mV has been completed.
Currently, the allowable input of the equalizer amplifier of Wo – 1 is adjusted slightly and it is used at 1800 mV.

Wo-1 has further improved from there.
It is natural to use good parts to make a good amp, but to make it even better it is important to omit useless parts.
In the design of the amplifier, the sound quality is better if the capacitor and the resistance are less in the conductor through which the music signal passes.
There is no problem with a certain number of capacitors, but resistance has to be omitted.
Among them, the most influential one is the resistance of the volume.
The sound signal loses 50% to 80% of energy by this volume resistance.
Also, the volume resistance greatly increases the impedance of the amplifier.
Even if you use high quality resistors for volume, the sound quality will not be solved.

In September 1997, I tried to eliminate the resistance of the volume.
I thought of adjusting the volume by changing the gain of the amplifier, and Wo-1 was completed in 1999.
Wo-1 has been further improved by 2014.
The amplification of this amplifier is 0 times to about 45 times.
The meter of the front panel is attached to manage the precise operation of the vacuum tube of this part.
In the circuit of Wo – 1, there is no resistance in the conductor through which the signal passes.

Wo-1 has another feature.
The output of a general high-end vacuum tube preamplifier uses a cathode follower circuit of a voltage amplifying tube (low power).
It is output with apparent low impedance (less energy due to 100% NFB), but in the Wo-1 2014 model, an output tube (high power) is used to lower the output impedance.
It outputs music signals with high energy of the plate follower circuit while maintaining the frequency characteristics.
As for what this means, most of the general preamplifier pretends as a good quality low impedance preamplifier.
Wo-1 is a genuine low impedance that is not a pretense.

In order to make Wo-1 you need technology and quantity that can not be thought of with normal pre – amps.
The sound quality feels a sense of transparency, speed, volume, sense of force, space and makes me think of the reproduction of live performance, but since it is an amplifier I made by myself, I will refrain from the impression here.
However, if you understand the essence of the design, I think you can understand that this preamplifier naturally has the best sound quality beyond common sense.

:Supplement:
Currently, Miyajima Laboratory’s products are exporting overseas, so when we sell amps overseas we need to adapt the standards of parts used to the world standards.
I am using a black tubular black cat capacitor in the circuit picture of WO – 1, but it is unknown whether RoHS of European standard is compatible for now.
When adding the CE mark to the amplifier, we are considering changing this capacitor.
All other parts are RoHS compliant.

:About the CE mark of the amplifier:
Since we are small manufacturers, we are short of information.
We are making an effort to acquire the CE mark, so please wait for a while.

We begin sale of OTL power amp MODEL2010. 
We need many preparations to sell an amplifier. 

Wiring : handmade

I do not use a circuit base.

Wiring for bias adjustment

I install favorite Black Cat last.(Completion)

A changeover switch of MONO/STEREO
&
ON/OFF of NFB (-2dB)
&
Speaker terminal

The transformer is made in Japan.

Name Plate

Bias

(The prediction data of the amplifier)
The frequency of this amplifier is very wide. 
10Hz – 100,000Hz (-1dB, 1W, non-NFB)
10Hz – 250,000Hz (-3dB, 1W, non-NFB)
The S/N ratio of this amplifier is very high. 

-Out-put-
non-NFB:Stereo 16ohm(12W+12W), 8ohm(7W+7W), Mono 8ohm(16W) Mono 4ohm(13W) 
　　　NFB:Stereo 16ohm(15W+15W), 8ohm(9W+9W), Mono 8ohm(22W), Mono 4ohm(18W) 

Weight:about 18.5kg 
Size:about W450 x H220 x D340 mm
The sound quality of this amplifier clear and powerful. 
This amplifier does play music obediently. 
This amplifier is long life.

The volume for professionals made by Alps
50kΩ type (for Vacume Tube amp)
10kΩ type (for Transistor amp)

About 820 g

Aluminum, Iron 
Aluminum

carved seal

Passive selector with the convenient volume

If you do not hear an LP, this selector is a superior pre-amp of the cost performance.
There is not an amplifier function to this selector.
This selector without the phonoequalizer cannot use an LP player.
INPUT to connect CD Player, PC, tuner, TV, etc to has 3 circuits.

OUTPUT to connect power amp to has 2 circuits.
About OUT PUT, one and both output are possible.
Because you can connect two power amp, you output the same sound source in two rooms and can change it to one room.
Please control a sound source by the volume.

REC is not influenced by the volume.
REC outputs a select sound source directly.

I recommend that you connect the power amp of the high class to this selector than you purchase an expensive pre-amp.