LL1933 Lundahl MC-Übertrager Mu-Metall MC-Stepup transfor.

Lundahl LL1933 premium mu-metal MC step-up transformer

The Lundahl LL1933 is a premium step-up transformer using a laminated nickel/mu-metal core and Cardas OFC windings. It raises a moving-coil cartridge signal passively by approximately 18 or 24 dB before feeding an MM phono input.

Its 1:8 and 1:16 ratios cover many widely used MC cartridges, including the Denon DL-103 and DL-103R, Rega Ania Pro, Goldring Eroica LX, Sumiko Songbird Low and similar designs.

Suitable applications

• Denon DL-103 and other medium-impedance MC cartridges
• Denon DL-103R, Rega Ania Pro and AT33PTG/2
• Goldring Eroica LX and Sumiko Songbird Low
• Premium phono DIY using a mu-metal core and Cardas OFC

Technical specifications

Transformer type

Passive MC step-up transformer, one channel per component

Core material

Laminated nickel/mu-metal core with a linear magnetisation characteristic

Winding wire

Cardas high-purity OFC copper

Winding construction

Symmetrical dual-coil structure for improved immunity to external magnetic fields

Step-up ratios

1:8 or 1:16

Voltage gain

Approximately 18.1 dB at 1:8 or 24.1 dB at 1:16

Cartridge load with a 47 kΩ MM input

Approximately 734 Ω at 1:8 or 184 Ω at 1:16 without additional loading

Data-sheet frequency response

Approximately 8 Hz to 100 kHz within ±1 dB using a 50 Ω source and open secondaries

Shielding

Mu-metal enclosure combined with dual-coil construction

Dimensions

Approximately 47 × 28 × 24 mm

Weight

Approximately 115 g

Stereo requirement

Two LL1933 transformers are required for stereo

Published listening context

Lundahl describes the mu-metal core as a classic, linear and low-distortion solution. Published comparisons characterised the LL1933 as providing slightly greater upper-bass and lower-midrange body than the amorphous LL1931 while retaining high transparency.

These impressions are not fixed product guarantees. Cartridge loading, enclosure design, grounding, cable capacitance and the phono stage all have a substantial influence on the final result.

Questions about choosing the correct MC transformer

Which Lundahl transformer suits a Denon DL-103?

The LL1933 at 1:8 is a practical starting point. The nominal 0.3 mV DL-103 output becomes approximately 2.4 mV, while a 47 kΩ MM input reflects about 734 Ω to the cartridge. The LL9226 at 1:10 may also be considered when more output is required.

Which step-up transformer suits a Goldring Eroica LX or Sumiko Songbird Low?

The LL1933 can be used at 1:8 with either cartridge, producing approximately 4 mV. When the cartridge should see a load closer to its manufacturer recommendation, an additional resistor may be connected across the transformer secondary.

Can I choose the LL1933 instead of the amorphous LL1931?

Yes, their ratios, premium winding construction and general applications are closely related. The LL1933 instead uses a laminated mu-metal core and is particularly attractive when linear magnetisation and a slightly fuller tonal balance are preferred.

Is the LL1933 at 1:16 suitable for a Denon DL-103R or Rega Ania Pro?

Yes, the DL-103R produces approximately 4 mV and the Ania Pro about 5.6 mV. A 47 kΩ MM input reflects approximately 184 Ω to the cartridge. A 1:8 connection may be preferable with a highly sensitive phono input or limited overload margin.