LL1931 Lundahl MC-Übertrager Amorphous MC-transformer

Lundahl LL1931 premium amorphous-core MC step-up transformer

The Lundahl LL1931 is a premium moving-coil step-up transformer for cartridges with low to medium output. Its amorphous cobalt core, Cardas OFC winding wire and symmetrical dual-coil construction are designed to raise the cartridge signal passively before an MM phono input.

Selectable 1:8 and 1:16 ratios allow the transformer to be matched to different cartridges and phono stages. Typical applications include the Denon DL-103 and DL-103R, Lyra Delos and Kleos, Goldring Eroica LX and compatible Ortofon SPU variants.

Suitable applications

• Premium passive gain ahead of a 47 kΩ MM phono input
• Denon DL-103 at 1:8 and DL-103R at 1:16
• Lyra Delos, Lyra Kleos and Goldring Eroica LX
• Balanced or unbalanced high-end phono DIY projects

Technical specifications

Transformer type

Passive moving-coil step-up transformer, one channel per component

Core material

Uncut amorphous cobalt strip core

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, selected by the external connection

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 secondary loading

Data-sheet frequency response

Approximately 10 Hz to 100 kHz within ±1 dB in series connection with a 50 Ω source and open secondaries

Shielding

Mu-metal enclosure with additional magnetic-field rejection from the dual-coil construction

Dimensions

Approximately 43 × 29 × 22 mm

Weight

Approximately 80 g

Stereo requirement

Two LL1931 transformers are required for stereo

Matching notes

A 0.6 mV Lyra Delos produces approximately 4.8 mV at 1:8. A 0.25 mV Denon DL-103R produces approximately 4 mV at 1:16. Final selection should also consider the gain and overload margin of the MM phono stage.

In Lundahl's published comparison, the amorphous LL1931 was perceived as particularly open, spacious and detail-focused. Systems requiring slightly more upper-bass and lower-midrange body may also be compared with the otherwise closely related mu-metal LL1933.

Questions about choosing the correct MC transformer

Which Lundahl transformer suits a Lyra Delos or Lyra Kleos?

The Lundahl LL1931 at 1:8 is a strong starting point. A 0.6 mV Delos produces approximately 4.8 mV, while a 0.5 mV Kleos produces about 4 mV. Both cartridges are specified for step-up transformers intended for low-impedance MC generators in this range.

Which premium step-up transformer suits a Denon DL-103R or Rega Ania Pro?

The Lundahl LL1931 can be connected at 1:16 for both cartridges. The DL-103R then produces approximately 4 mV and the Ania Pro about 5.6 mV. A 1:8 connection may be preferable when the MM phono stage has high sensitivity or less gain is required.

Can I use the LL1931 instead of the LL1933?

Yes, both models provide 1:8 and 1:16 ratios, Cardas OFC windings, dual coils and mu-metal shielding. The main difference is the core: the LL1931 uses amorphous cobalt, while the LL1933 uses laminated mu-metal. The choice can therefore reflect the intended technical and tonal balance.

Is the LL1931 suitable for an Ortofon SPU Royal G MkII?

Yes, the 0.2 mV, 7 Ω SPU Royal G MkII can be used at 1:16. Calculated output is approximately 3.2 mV and the reflected load from a 47 kΩ input is about 184 Ω. For the quieter 2 Ω SPU Classic, the LL1941 is more flexible because it also provides 1:32.