Harmonia V3.1 - DHT Input Selector / Output Stage

Bring the coveted sound of the 2A3 or 300B home to any system with the Harmonia V3.1 input selector and output stage. The Harmonia is like no other in the world as it is not a simple tube buffer, but a true DHT output stage. Many tube buffers are simply cathode follower circuits designed to create even order distortion, causing some loss in resolution for the sake of interjecting some tube "sweetness" to the sound. The simplicity of a DHT stage better preserves the signal while introducing true sonic richness, an expansive soundstage, and true magic in the midrange. 

As with all components available here at Quark Audio, every Musical Bella product is built to order. This allows for many more options and customization while focusing on the sound and performance of the product. Pictures are indicative of what is possible of a Musica Bella product, but many other aesthetic options are available. New chassis design to be released soon for the updated Harmonia V3.1, previous design pictured.

Features

The sound of a directly heated triode, or DHT, has been a long time favorite of audiophiles, and for good reason. Single ended DHT are simpler than most modern tubes, meaning a simpler circuit and signal path that equates to less damage to the signal. Then there is the positive of adding even order harmonics to the sound for more natural overtones that much solid state lacks. 

DHT tubes are not without their drawbacks, the implementation is critical, and for this reason sometimes a DHT based amplifier or preamp does not pair well with a modern system. The Harmonia is thoughtfully designed to bring out the best of the 2A3 or 300B tube in any system, allowing you to use whatever amplifier best suits your system even in home theater. 

The best implementation of the Harmonia is as a source selector between your sources and preamplifier, or within the tape loop / effects channel of integrated amplifiers, receivers, or preamps. (If unsure, please reach out for assistance for best placement, please note that when used between a preamp and power amplifier, there is a potential for noise)

Getting The DHT Right

The Harmonia is a true performer and a result of passion and years of research to deliver something truly unique and effective. All of the typical caveats of a DHT have been considered in the design with careful attention paid to the power supply, circuit topography, and microphonics. Every unit is hand assembled with point to point wiring throughout, and utilizes passive components that have been specially selected to breathe life into the music while preserving extension and detail. 

The power supply is robust and designed for the for the sensitivity and high current requirements of DHT. Each of the tube filaments have separate, fully regulated DC power supplies that are freshly redesigned for 2024 for the V3 series, allowing for a stable 2.5V or 5v depending on the tube. Special care has also been taken on the main B+, using separate transformers and choke loaded anodes on each 300B tube, a much quieter alternative than feeding the plate voltage from a capacitor or resistor. 

The Sound - Notes from designer Bill Baker

• Restores proper frequency balance through better impedance matching due to its extremely low output impedance
• Improves tone and weight without adding bloom
• Adds DHT smoothness, richness and organic qualities to sterile or dry solid state and tube source components
• Improves dynamics of source components that do not employ proper impedance matching
• Enhances detail, resolution and transparency
• Reduces listener fatigue
• Enhances the 3D sound-staging of better electronics and recordings

Options / Customizations

The Harmonia is available in single ended or balanced design using quality Neutrik RCA and/or XLR connectors. In the balanced variant, both the inputs and outputs are transformer coupled with a rear mounted ground lift switch to ensure quiet operation regardless of the components used with the DHT stage. The entire chassis has been well damped to reduce any risk of microphonics or unwanted interaction between components. 

For high efficiency or high gain systems, the Harmonia can also be ordered as a zero gain DHT preamplifier with an included volume remote. 

The power supply uses UF diodes for the rectification stage, a 5AR4 tube based rectifier power supply is available on request. 

The Harmonia currently comes in a charcoal powder coated chassis with a laser engraved front faceplate in a color of your choosing. Please reach out for other considerations or inquiries. 

Specifications

Output Gain:                  <1dB

Output Impedance:       180Ω Balanced 

                                       150Ω Single Ended

Tubes:                            (1) 2A3 or 300B per channel

Please note that this is a made to order product. Prices are a base level estimated cost for a standard build, does not include vacuum tubes for 300B variant. Other costs may apply for customizations, please message us with your inquiries for a total cost with any considerations or to order your Harmonia V3.1.