Step-Up Transformer
A step-up transformer (SUT) is a passive box that raises a low-output moving-coil (MC) cartridge’s voltage for a moving-magnet (MM) phono input. It needs no power supply.
Connect the cartridge to the SUT, then the SUT to the MM phono input. The phono stage still adds gain and RIAA equalisation, the tonal correction for record playback, before feeding the amplifier. A suitably matched MC phono input can work without a separate SUT.
Choose a transformer using the cartridge’s output voltage, internal impedance and recommended load. Check these against the transformer’s recommendations and the MM stage’s input load and signal-level requirements.
Turns ratio describes the approximate voltage multiplication. A higher ratio also lowers the reflected load—the impedance the cartridge sees—when the secondary load at the transformer’s output stays the same. More gain is not automatically better.
The catalogue labels “RCA Line Input” and “RCA Line Output” refer here to sockets carrying phono-level signals. The SUT cannot feed a line input directly.
Required capabilities
Specifications
This list covers specifications tracked for the category. A specification may describe several functions; follow the capability label that matches your use. A listing does not confirm a feature on an individual product.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
- Specification in preparation
Some capability explanations are in preparation.
Sources
- Pro-Ject MC Step Up Box S3 — instructions for use — Pro-Ject Audio Systems
- SUT Calculations — Erhard Audio
- Pro-Ject Phono Box MM — product information — Pro-Ject Audio Systems
- Moving coil input transformers — Lundahl Transformers
- Phono Box S2 — Pro-Ject Audio Systems
- Pro-Ject FAQ — Pro-Ject Audio Systems