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Various / Other Expressive Technologies SU-1 MC Step-Up Transformer / Ultra-Rare / 16kg
Product information
- Product category
- Phono Amplifier
- Manufacturer
- Various / Other
- Function
- flawless
- Age
- 34 years By estimate
- Usage state
- second-hand
- Appearance
- as good as new
- Accessories
- without accessories
- Color
- Black
- Original price
- 7,500.00 €
- Price
- 4,500.00 €
- Serial number
- no serial number
Description
An exceptionally rare instrument — in original, unopened factory condition.
The Expressive Technologies SU-1 is not a conventional step-up transformer. It is a 15.9 kg (35 lb) industrial-grade component engineered to provide the absolute lowest noise floor and highest dynamic range achievable for low-output MC cartridges — a singular statement of purpose from a company that made almost nothing else.
The mass is functional: the custom-wound transformer cores are encapsulated in a proprietary damping compound to eliminate mechanical resonance, ensuring that the cartridge's micro-signals are never modulated by external vibration. A dual-mono, multi-layer Faraday shield provides comprehensive RFI/EMI rejection in high-gain environments.
Technical Verification — External DCR Bench Analysis:
The integrity of the original nickel-lamination transformers has been independently verified:
Key Specifications:
Condition & Provenance:
An unnumbered early-production specimen from the Kuzma collection (Ljubljana, Slovenia), curated by Franc Kuzma, founder of Kuzma Audio. Stored in a climate-controlled environment. Faceplate pristine.
In this collection, the SU-1 served as the primary interface for a Kuzma KC-Reference silver-coil cartridge (0.24mV output) — the 25:1 ratio chosen specifically for its dynamic headroom with ultra-low-output transducers.
Note on accessories: IC-1 proprietary interconnect cables are not included. The unit terminates in standard RCA.
Serious buyers: Live inspection via Discord, YouTube or Twitch available before committing. Bill of sale provided. Price negotiable within reason.
MATCHED SYSTEM: The Conrad-Johnson Premier 7B & 8A stack from the same Kuzma collection is also listed. Both pieces were used together as a complete reference front-end — see my other listings.
The Expressive Technologies SU-1 is not a conventional step-up transformer. It is a 15.9 kg (35 lb) industrial-grade component engineered to provide the absolute lowest noise floor and highest dynamic range achievable for low-output MC cartridges — a singular statement of purpose from a company that made almost nothing else.
The mass is functional: the custom-wound transformer cores are encapsulated in a proprietary damping compound to eliminate mechanical resonance, ensuring that the cartridge's micro-signals are never modulated by external vibration. A dual-mono, multi-layer Faraday shield provides comprehensive RFI/EMI rejection in high-gain environments.
Technical Verification — External DCR Bench Analysis:
The integrity of the original nickel-lamination transformers has been independently verified:
- Primary (Input): 0.2 Ω / 0.2 Ω — 100% symmetrical
- Secondary (Output): 230 Ω / 227 Ω — matched within 1.3%
- Galvanic Isolation: Infinite Ω — verified 100% stage separation
- Shielding: 0.2 Ω continuity confirmed between ground lug and Faraday cages
Key Specifications:
- Gain: 28 dB (25:1 turns ratio)
- Weight: 15.9 kg / 35 lbs
- Optimized for: Ultra-low output MC cartridges — Ortofon MC Anna, Koetsu, Lyra, Kuzma CAR-40/50/60 series and equivalents
- Terminations: Standard high-quality RCA — compatible with reference interconnects of your choice
Condition & Provenance:
An unnumbered early-production specimen from the Kuzma collection (Ljubljana, Slovenia), curated by Franc Kuzma, founder of Kuzma Audio. Stored in a climate-controlled environment. Faceplate pristine.
In this collection, the SU-1 served as the primary interface for a Kuzma KC-Reference silver-coil cartridge (0.24mV output) — the 25:1 ratio chosen specifically for its dynamic headroom with ultra-low-output transducers.
Note on accessories: IC-1 proprietary interconnect cables are not included. The unit terminates in standard RCA.
Serious buyers: Live inspection via Discord, YouTube or Twitch available before committing. Bill of sale provided. Price negotiable within reason.
MATCHED SYSTEM: The Conrad-Johnson Premier 7B & 8A stack from the same Kuzma collection is also listed. Both pieces were used together as a complete reference front-end — see my other listings.
Seller:
- Shipping from Slovenia (1000)
- Purchaser pays shipping costs
- Worldwide shipping
Payment methods
- Cash upon collection
- Bank transfer
Advert ID
6250430644
Advert time period- Start:
- 23.02.2026 - 22:42
- End:
- 24.04.2026 - 22:42
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