fonolab DECVS Ultra-Low Output MC Dedicated Balanced Step-Up Transformer

Very low-output MCs are actually difficult to drive

The delicacy contained in tiny signals,holographic soundstagethe warmth—there are countless reasons why very low-output MC cartridges are loved. However, it is not easy to draw out their true potential. The lower the output, the more gain is required, and if you increase gain with a phono preamp, noise also increases. The subtle nuances get buried under a hiss of noise or thin sound—haven't you experienced that? The DECVS is a dedicated step-up transformer designed precisely for the challenge of "how to drive very low-output MCs."

■ Not 'one for everything,' but 'focused on this one alone'

Many transformers are equipped with switching options or multiple paths to accommodate various cartridges. While convenient, compromises inevitably arise. The DECVS takes the opposite approach. It has no switches and is a fixed structure aimed solely at small-output, low-impedance MCs. By concentrating the operating conditions on a single point, it achieves the shortest and purest signal path and unwavering reference performance.

The full balance produces jet-black quietness and density

DECVS uses independent transformers for each signal phase, designing the shielding, grounding, and mechanical structure as an integrated whole. It is a thoroughly engineered structure that not only achieves a high step-up ratio but also accurately transmits tiny signals while protecting them from external noise. With carefully selected transformer pairs operating in full balance, noise and hum cancel each other out, and the music rises from pitch-black silence. It also has high channel independence (channel separation of over 80dB), clearly separating each instrument's position and enhancing the clarity of the soundstage. The high step-up ratio of 1:36 raises tiny MC signals with ample headroom, producing a dense sound image without thinness or stress. The outputs support both RCA and XLR, allowing flexible connection to your phono preamp, and with a balanced device, you can take it a step further using XLR.

A solid foundation: Rigid chassis and grounding

For transformers handling tiny signals, being 'quiet' both mechanically and electrically is essential. The DECVS suppresses vibration with a highly rigid steel chassis, which also serves as magnetic shielding. Additionally, it is equipped with isolated grounds and a ground lift mechanism, carefully managing ground loops even in complex systems with multiple devices. All of this is densely and precisely incorporated on the compact FUCHS platform.

Recommended for:

Those who use MC cartridges with very low output (generally around 0.2mV or less), those troubled by insufficient gain or noise in their phono preamps, and those who prefer 'perfect performance for one role' rather than 'one device for everything.' Users with an already satisfying analog setup will especially notice the difference in silence and density.

Main Features

• Dedicated design for very low-output MC cartridges:Focused on low-impedance cartridges, delivering stable performance through uncompromising fixed construction.
• High 1:36 step-up ratio:Ample amplification of tiny MC signals, producing a sound image without thinness or stress.
• Excellent channel separation (over 80dB):Clearly separates left and right, enhancing localization and soundstage clarity.
• Full balance & floating RCA input:Differential transmission from the input stage, achieving noise-suppressed, pitch-black silence.
• Both RCA and XLR outputs.Supports both unbalanced and balanced phono EQs flexibly.
• Rigid Steel Chassis: Suppresses vibrations and also functions as a magnetic shield. Protects minute signals from interference.
• Isolated Grounding: Manages ground loops with a ground lift mechanism and enhances quietness.

Installation Points:Because it has a high step-up ratio, place it away from devices that generate strong magnetic fields, such as power transformers or AC adapters. Proper selection of the installation location will enable extremely quiet operation.

Overseas Review: LP Magazin – Quietly and smoothly brings out the charm of ultra-low output MC

The German analog magazine 'LP Magazin' has tested the Fonolab DECVS as a full-fledged dedicated device for ultra-low output MC cartridges.Attention is also being paid to designs that handle signals in a fully balanced configuration, including RCA inputs. For listening tests, the Sculpture A MC 5.3 with a nominal output of 0.1 mV was used. By combining the DECVS's approximate 31 dB boost with the gain of a typical MM phono equalizer, it has been reported that a sufficient amplification level is achieved to handle ultra-low output MCs without difficulty.

■ Boosting 0.1 mV-class MCs to an appropriate level

Even with a cartridge that has an extremely low nominal output of 0.1 mV, passing it through the DECVS boosts it to about 3.6 mV, providing a signal level that is manageable for the downstream MM phono equalizer. Additionally, when connected to a 47 kΩ MM input, the load as seen from the cartridge side is about 36 Ω, which is evaluated as providing suitable operating conditions for low-impedance, low-output MCs.

■ Quiet and natural playback without noticeable noise

According to reviews, despite such a high level of boost, if appropriately installed, noise is not a problem, resulting in an extremely quiet background. The sound quality is smooth and elegant, yet direct. It has been highly praised for conveying not just the softness of the tone but also the momentum of instruments and the tension of the performance without compromise.

■ Musical expression that balances smoothness and vividness

In Pink Floyd, the guitar intro is reproduced with strong presence and beauty; in Rickie Lee Jones, the emotional depth of the vocals and performance is clearly depicted. In Chuck Mangione's powerful brass music, brilliance and smoothness coexist naturally, reproducing the explosive dynamics of the piece convincingly without causing any harshness or irritation.

■ Internal design thoroughly implementing a fully balanced structure

This has been introduced in 'LP Magazin.'

■ Overall review

'LP Magazin' concludes that the DECVS is an excellent step-up transformer suitable for MC cartridges with extremely low output voltage, easy to handle, with very smooth sound quality that is direct yet naturally coherent. It is especially praised for extracting the delicacy unique to ultra-low output MCs while also drawing out the density, vitality, and emotional expression of the music.