SFz-E MC Transformer

Key Features

• Passive moving-coil step-up transformer
• Developed from the reference Kondo SFz
• Pure-silver multilayer transformer windings
• Separate Low and High cartridge-impedance inputs
• Low input for cartridges with 1–10-ohm internal impedance
• High input for cartridges with 11–40-ohm internal impedance
• 34 dB or 20 dB step-up gain
• Large core made from ultra-thin 100 µm Permalloy laminations
• Frequency response extending to 100 kHz
• Direct winding-to-terminal connections
• Minimized mechanical contact points
• Double-layer magnetic and electrostatic shielding
• Permalloy transformer case and copper inner chassis
• Double-float mechanical damping
• Transformer suspended with damping gel
• Special vibration-absorbing rubber feet
• Simplified design without a grounding-mode selector
• Passive operation requiring no power connection

Design & Build

The SFz-E continues a Kondo tradition that began with the company’s original Silvered Former moving-coil transformer. It inherits the principal technologies of the reference SFz while using a simplified connection arrangement without the SFz’s balanced/unbalanced grounding selector.

Its transformers use pure-silver wire arranged in a multilayer winding structure. This construction maintains a flat response to 100 kHz, with secondary peaking held below 1.5 dB when no terminating resistor is connected.

The magnetic core is meticulously assembled from custom 100 µm Permalloy sheets. These exceptionally thin laminations reduce eddy-current and hysteresis losses, supporting wide bandwidth, low-frequency extension and low distortion.

Each transformer is mounted inside a Permalloy case and surrounded by an inner copper chassis. The two materials provide complementary protection against magnetic and electrostatic interference. Damping gel and specially selected rubber feet isolate the transformer from external vibration.

System Pairing

The Low input provides 34 dB of gain and is designed for moving-coil cartridges with an internal impedance between 1 and 10 ohms. It is therefore suitable for Kondo’s 1-ohm IO-XP cartridge.

The High input provides 20 dB of gain and accommodates moving-coil cartridges with an internal impedance between 11 and 40 ohms. Only one pair of cartridge inputs should be connected at a time.

The SFz-E’s output should be connected to a conventional 47-kohm moving-magnet phono input, such as those fitted to Kondo’s GE-series phono amplifiers or M7 Heritage preamplifier. Its entirely passive architecture requires no external power supply.