Ortofon
ST-70 MC Transformer
Best step-up transformer for audiophiles seeking pure moving coil cartridge performance.
The Ortofon ST-70 MC Step Up Transformer is engineered for discerning audiophiles, delivering unparalleled sound reproduction. It features premium Lundahl™ transformers with specialized mu-metal shielding for exceptional purity and minimal interference. The dual mono design ensures discrete circuitry, eliminating crosstalk and enhancing stereo imaging for an accurate tonal balance. High-quality industrial PCBs and gold-plated RCA jacks minimize signal degradation. With selectable gain and impedance options, the ST-70 offers broad compatibility with most Moving Coil cartridges, making it an ideal choice for maximizing their performance.
$1759.00
Owner Satisfaction
4.7
/ 5
Category Rank
86
/ 466
#86 in Phono Preamps
Price vs Category Average
-74%
Below average
Configuration A - Recommended Cartridge Impedance
550
/ – Ω
Who it's for
- Vinyl collectors using diverse low-output moving coil cartridges
- Listeners prioritizing a quiet, interference-free analog signal path
- Audiophiles seeking the natural, dynamic sound of passive amplification
Who should skip it
- Owners with limited space for careful component isolation
- Budget-conscious listeners looking for entry-level phono solutions
- Users lacking a high-quality moving magnet phono stage
Performance breakdown
Signal Purity
Passive design and mu-metal shielding virtually eliminate unwanted electrical noise.
Cartridge Compatibility
Selectable gain and impedance settings accommodate a vast range of MC cartridges.
Stereo Imaging
Dual mono circuitry ensures precise channel separation for a lifelike soundstage.
Build Integrity
Industrial-grade PCBs and gold-plated jacks provide a robust, reliable signal path.
Frequency Response
Wide bandwidth performance captures subtle nuances across the entire audible spectrum.
Ease of Integration
Requires careful matching with your existing phono stage for optimal results.
Key Specs
Configuration A - Recommended Cartridge Impedance
5–50 Ω
Configuration A - Gain at 1 kHz
24 dB
Configuration A - Frequency Response
10 Hz – 100 kHz ± 1 dB
Configuration A - Recommended Load
47 kΩ // 200 pF
Configuration B - Recommended Cartridge Impedance
< 10 Ω
Configuration B - Gain at 1 kHz
30 dB
Configuration B - Frequency Response
10 Hz – 80 kHz ± 1 dB
Configuration B - Recommended Load
47 kΩ // 200 pF
Features
- High-quality Lundahl™ transformers for exceptional detail.
- Mu-metal shielding minimizes interference for pure sound.
- Dual mono design eliminates crosstalk and enhances imaging.
- Gold-plated RCA jacks ensure optimal signal flow.
- Selectable gain/impedance for wide cartridge compatibility.
- Passive design for superior noise performance.
- Delivers lifelike stereo imaging.
- Pristine signal integrity.
What customers say
The Ortofon ST-70 transformer earns high praise for its exceptional sonic performance, significantly elevating vinyl playback quality. Users consistently report profound improvements in soundstage depth, dynamic range, and overall musicality. The sound is described as natural and warm, allowing high-end MC cartridges to reveal their best qualities. A key feature appreciated is the versatility provided by dual primary windings, ensuring optimal impedance matching for various cartridges. Build quality is universally lauded; the unit feels robust and premium. While the investment is substantial, enthusiasts agree the ST-70 delivers transformative listening experiences, making it a worthwhile, long-term component that often outperforms similarly priced active stages.
Know before you buy
The ST-70 is a passive step-up transformer designed to boost the low-level signal of Moving Coil (MC) cartridges to a level compatible with standard Moving Magnet (MM) phono inputs. It does not require external power, ensuring a completely noise-free signal path.
The ST-70 offers two configuration settings to accommodate different cartridge impedances. Configuration A is best for cartridges with an impedance between 5 and 50 Ω, while Configuration B is designed for cartridges with an impedance of less than 10 Ω.
The dual mono design separates the circuitry for the left and right channels entirely. This eliminates crosstalk, which results in significantly improved stereo imaging and a more precise soundstage.
No, the ST-70 is a passive device. It uses high-quality Lundahl™ transformers to step up the voltage, which avoids the electrical noise often introduced by active power supplies.
No, the ST-70 is specifically engineered for Moving Coil (MC) cartridges. It is not designed to be used with Moving Magnet cartridges, as they do not require the additional gain provided by a step-up transformer.
Mu-metal is a specialized alloy used to shield sensitive internal components from electromagnetic interference. In a phono stage, this is critical for maintaining a pure, quiet signal and preventing hum or external noise from coloring your music.
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$1759