This is a 3-step amplification NF equalizer based on 12AX7, which applies NFB from the 3rd stage cathode to the 1st stage cathode.(so-called “K-K type”).

The advantage of the NFB type is that it does not require a high gain level and is not very sensitive to tube quality. However, the impedance of NFB at high frequency range becomes very low and results in a negative effect – the sound becomes hard and dry.

The NFB type is usually used as it is an easier way to attain a good signal-to-noise ratio.

As for the CR type, a masterpiece preamplifier equipped with the CR type equalizer is the vintage Harman-Kardon Model: “Citation IV”.

CR type equalization requires a high gain level and is much more sensitive to tube quality.

Since tube quality will be directly amplified, the finest possible quality tubes are needed for this type of equalizer. Moreover, proper implementation is more difficult.

However, the CR type is much more superior sonically to the NFB type, being very stable in the high frequency range and is able to reproduce a very high quality sound especially when high quality tubes are used.

specifications

Tube Complement: 2 x 6CG7 (G.E.); 2 x 12AT7 (G.E.); 1 x 5Y3WGT

RIAA Curve; <0,3 dB

Gain phono: 20,2 dB

Input: 400 mV (2KHz)

Gain line: 25,2 dB

Output: 80V

Output Impedance: 580Ohms

Weight: kg 13.5 (main body+ power supply)