VICTOR/JVC EQ-7070

Commentary

This is a Laboratory 7070 series phono equalizer using EL-FET.

The EQ-7070 is a phono equalizer with many inputs and can be used as a control amplifier.

The EQ 7070 is equipped with a newly developed EL-FET.
The EL-FET has a very high mutual inductance Gm (I)._DIt has a Gm of 55 m Ω at 10 mA, more than 8 times the conventional high GmFET) and can design an ultra-low noise amplifier. In addition to excellent S/N and compactness, it has a feature of ICL configuration without input capacitors. It can prevent low-frequency phase rotation by using a direct-coupled circuit.

Five EL-FETs are connected in parallel in the first stage of the MC head amplifier and a bipolar power transistor with a cutoff frequency of 140 MHz is also used in the next stage to form an inverted Darlington connected SRPP output circuit with low distortion.
In addition, high linearity is ensured by flowing a large current of 50 mA in one channel, and high S/N ratio is realized by sufficient high Gm and sufficient dynamic range.

A newly developed EL-FET is also used in the first stage of the equalizer section. A high signal-to-noise ratio is achieved by combining it with a high-voltage bipolar transistor. The total gain of the equalizer including the MC head amplifier is 77 dB. Even when the equalizer output and power amplifier are connected directly without a flat amplifier, sufficient volume can be obtained.

The flat amplifier is a symmetric push-pull drive circuit using a high voltage dual FET at the first stage.
The gain is 16 dB.

It is equipped with an auxiliary and tuner selector and an independent phono selector, which can switch between MC and MM without changing the connection of the rear panel.
In the MM position, the cartridge load selector with 4-step switching of load resistance and load capacity is activated. The 100 Ω position of the load resistance selector is for high-power MC cartridges.

As a control amplifier, it is equipped with two tape monitor circuits and Aux and Tuner input terminals.

Low distortion rate multi-contact 6-series volume is used for volume.
This volume uses 14 high-precision multi-contact sliders and special shaped resistors to reduce distortion due to current concentration. Two series are for balance and the other four series are special 6-series volume that adjusts gain before and after the flat amplifier.
The latter element works only at -30dB or less and reduces residual noise to improve the S/N of the hearing sense at low volume.
In addition, the volume itself is resistant to external noise by adopting a die-cast cover, and crosstalk between channels is also improved.

The power supply circuit employs a large-capacity left-and-right independently wound toroidal transformer with six double shields to completely remove leakage flux. In addition, by adding a constant voltage circuit using a wide-band transistor (ft 140 MHz) for signal circuits, the internal impedance is suppressed to less than 0.01 Ω up to 100 kHz.
We have adopted electrolytic capacitors with specially examined electrode materials and structures.

There was a rack handle as an option sold separately.

Model Rating

Type	Stereo phono equalizer amplifier
Circuit system	MC Head Amplifier : EL-FET / ICL Equalizer amplifier : First stage EL-FET cascode, double differential common-mode feedback ICL, DC configuration Flat Amplifier : First Stage High Voltage FET Symmetric Push-Pull Drive ICL / DC Configuration
Input Sensitivity / Impedance	Phono1 MC (high) : 0.1mV/11 Ω Phono2 mc (low) : 0.025mV/2.5 Ω Phono1/2/3 mm : 1.8mV/100 Ω, 33k Ω, 50k Ω, 100k Ω / 100 pF, 220 pF, 330 pF, 470 pF
Phono maximum allowable input	Phono1 MC(high):15mV(1kHz) Phono2 MC(low):3.8mV(1kHz) Phono1/2/3/ MM:300mV(1kHz)
Frequency characteristic	Phono : 30 Hz to 15 kHz ± 0.2 dB (at Rec out terminal) Tuner and Aux : 10 Hz to 100 kHz + 0 -1dB at Pre-out terminal
Signal-to-noise ratio	Phono1 MC (high) : -151dBV (input conversion IHF-A, input 10 Ω short) 73 dB (IHF-A, Input 10 Ω Short, 0.1 mV Input) Phono2 mc (low) : -160dBV (input conversion IHF-A, input 10 Ω short) 82 dB (IHF-A, Input 10 Ω Short, 0.1 mV Input) 70 dB (IHF-A, Input 10 Ω short, 0.025 mV input) Phono1/2/3 mm : -140dBV (Input Conversion IFF-A, Input Short) 100 dB (IHF-A, Input Short, 10 mV Input) 85 dB (IHF-A, Input Short, 1.8 mV Input) Tuner, Aux : -120dBV (input conversion IHF-A, input short) 104 dB (IHF-A, input short, 160 mV input)
Total harmonic distortion factor	Phono1 MC (high) : 0.003% (1 kHz, 5 v, Rec out) Phono2 mc (low) : 0.005% (1 kHz, 5 v, Rec out) Phono1/2/3 mm : 0.002% (1 kHz, 5 V, Rec out) Tuner, Aux : 0.002% (1 khz, 5 v, pre-out)
Output Level / Impedance	Pre out : 1V/50 Ω (Rating), 15 V (Maximum)
Power consumption	33W (Electrical Appliance and Material Control Law)
External dimensions	Width 420x Height 61x Depth 378 mm
Weight	7.5kg
Sold Separately	Rack Handle BH-50 (¥ 3,500)