Interview with owner, producer and sound engineer Nicolas Stawski, extract: “This is the result of a lot of deep reflections…Seguir leyendo >
|– Sensibility||All models have the same voltage gain (which eases multi-amplification)|
|– Impedance||20 KΩ|
|– Conection||3 pin XLR – metal housed, gold contacts|
|– Common mode rejection||100dB CMRR, based on psychoacoustic criteria since 2012.|
|– Type||High precision balanced input stage (impedance matched to PRS1.5)|
|– Monitoring||Level metering on bargraph (-15dB to +3dB) (except HQS1050: -3dB, +3dB)
Input offset, overload and high temperature indicated by LEDs
|– Output power RMS||
|– Output stage current capability||HQS9001: 330A, HQS7001: 112A, HQS6002: 80A/channel|
|– Operation load limit||HQS9001: 1Ω (operational) HQS7001/6002: 1Ω (limited) HQS1050: 2Ω (limited) (automatic current limiting on permanent loading)|
|– Conection||JMF Audio dia. 6mm terminals (120A continuous rated) (adapters to 4mm provided). The HQS1050 additionaly features WBT gold terminals for fork and banana|
|– Monitoring||Full output power and high temperature indicated by LEDs|
|Noise floor and hum||Better than -125dB (mono) -122dB (stereo) un-weighted a 1kHz (2012 measures)|
|Bandwidth||3Hz – 100 kHz (-3dB), 3Hz – 40kHz (0dB)|
|Audio signal coupling||DC coupled (exclusive DC servo circuitry)|
|Protection circuits||Automatic protection against high frequency large signals
Automatic DC protection below 3Hz
Automatic protection against overheating and input offset
Automatic protection against overload and short circuits
|Dimensions and weight||483 W x 550 D x 183 H* mm (HQS9001-F new massive aluminum chassis – without fan unit and including feet), 52 Kg each
483 W x 500 D x 140 H* mm (HQS7001, HQS6002 – without fan unit and including feet), 25 Kg each
|Power supply||100V AC, 120V AC, 230V AC (HQS9001, HQS7001, HQS6002 internal selection)
100V AC .. 240V AC (HQS1050 automatic)
The HQS9001 is equipped with mains voltage supervision circuits and would not power up may the actual mains voltage be different from the selection.
|Fan unit (HQS9001)||Silent, automatic and variable speed fan unit, no air path inside amplifier (no dust)|
Driving the loudspeakers… Caring for the music…
The JMF Audio HQS power amplifiers have been acclaimed for their high output power combined with a faithful, natural rendering of music. Since 1988, the most influential audio professionals, such as American studio designer Tom Hidley, and world-class studios (Nashville, New-York, London, Capri, Tokyo, Paris…) have trusted the HQS power amplifiers to monitor the quality of the recordings and productions, with great pleasure of listening.
While it first met with success in the studios, the JMF Audio technology was humbly aimed at celebrating music, for all music lovers.
Jean-Marie Fusilier designed and built the HQS power amplifiers without the preconceptions, the marketing considerations, the deadlines or budgets that generally limit commercial designs. Being an expert engineer in high-frequency, infra-red and power electronics, Jean-Marie Fusilier approached audio differently, by passion, with pragmatism, and developed innovative solutions. These set the fundamentals of the make JMF Audio, established in 1985.
The JMF Audio founder desired a lively yet controlled rendering for all types of musics… Even with high sensitivity loudspeakers, this meant significant driving force, precision and very low noise floor. The tube technology which he used to cherish was therefore left aside. Regarding the solid state technology, it was common belief that only a pair of matched output transistors could lead to musicality, which was still only suitable for intimistic listening.
Jean-Marie Fusilier took up the challenge to design a high output power amplifier offering a superb musicality.
The philosophy behind the JMF Audio HQS power amplifiers can be summarized as follows:
> A huge reserve of energy for instant delivery at the output on fortissimo. Achieved with the proprietary RPS concept involving bespoke toroidal transformers and bespoke high performance capacitors.
> High voltage electronics for superior headroom and higher efficiency. A linear amplification by design, a short signal path starting with a precision trimmed balanced input stage. These are key features of the LDA driver board, the center piece.
> High current output capability for best possible control, allowing the amplification structure not to rely on compensations such as feedback loops, yet featuring a high damping factor by nature. The base of the proprietary MTP concept.
A philosophy as set in the beginning and still followed today, sometimes with the exact same components…
Complementing the major aspects, the details are of significant importance regarding the musical result:
Since their introduction, the JMF Audio HQS power amplifiers have taken advantage of the long researches of their designer on the sound neutrality of passive components, semiconductors and materials as well as on the amplification structure allowing fast response, stability and linearity at every stage. The JMF Audio HQS power amplifiers utilize selected and uncommon components for audio applications: high frequency precision transistors, matched differential pairs, bespoke passive components, selected and noble materials…
Due to the requirements for specific components from the aeronautic, aerospace and fast-train industries located in France, some companies have specialized in providing custom parts. Thanks to our initial activities in high-frequency electronics, as told in the History of the brand, we have collaborated for over 30 years with such specialists, which allowed JMF Audio to obtain the bespoke components and parts, especially passive, that best suited our criteria, for serving music.