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The new CHFC1 high frequency driver, the heaviest and one of the biggest drivers devised, 34 Lbs. 10 Oz of iron and copper !  The ultimate field coil driver, with a huge 10 Lbs field coil capable of an extremely powerful magnetic field that requires 28V dc at 0.67 amp for negligible heat generation. A variable regulated DC power supply capable of supplying up to 32V dc at 2 amps or more will be fine for both coils working in parallel..Current regulated preferred

A beautiful all wood back cover that provides a natural low reflective dome to the back wave of the driver, attaining the most natural sound possible. all metal reflecting surfaces are avoided, simply one of the best high frequency drivers on earth !

 

For the ultimate in sound reproduction a field coil driver is unsurpassed ! Very smooth, warm, and musical ! Total weight, each:34 Lbs 10 Oz. Field Coil weight 10 Lbs. min. Field Coil power consumption at recommended settings: 28V @ 0.67A 18.8W 30V @ 0.8A 24W max. Available in 8 or 16 Ohms Shipping Worldwide Shipped in one double box with an approximated weight of 75Lbs. measuring 15 x 15 x 14 inches approximately. Shipping not included in the price. Please email for other shipping options or international quote before buying. Shipping in about 8 to 10 weeks after receiving payment. A 30-day refund if not 100% satisfied with the CHFC1 field coil drivers. Providing there is no damage and returned in the same condition as received. The buyer is responsible for shipping, bot h ways and Custom expenses. A re-stocking fee of 25% of the total sale price is charged for any returned item. 5 Years limited Warranty. CH Audio Design will repair or replace the CHFC1 field coil driver against any manufacturing defects in materials and workmanship for five years from the delivery date, providing they are not damaged by exposing to rain, water, high humidity, burned by excessive heat due to overpower, burned diaphragm coils, dropped, broken, or modified. CHFC1 Price. (per pair) US $3,275 ( includes all aluminum diaphragms.) Power supply not included. Special low noise zero recovery diodes power supplies available for all drivers. Presently 8 to 10 weeks lead time after full payment. CH Audio Design, Co. (Chela Audio) Email: mail@chelaaudio.com

 

 Shown in the graphics the response curves of a CHFC1 28Vdc Field Coil driver with 10, 20, 25,and 30 Volts applied to the field coil. Measurements taken at the throat of the driver.

Final frequency response will vary according to the load and frequency characteristics of the horn used.

Measurements taken with color identifying curves at the following field coil applied potentials:
Orange 10V
Green   20V
Blue     25V
Red      30V    (do not apply higher than 31Volts potential for continuous use)


The driver may be operated with a field coil voltage from 24 to 30 Vdc.
Operating preferred voltage 28 Volts DC

 The magnetic field strength is directly proportional to the power applied to the field coil up to saturation where an increase of power to the field coil won't increase the strength of the magnetic field and all that extra energy will be wasted as heat. In this configuration the best compromise is at 28 Volts dc, keeping the heat generation at a minimum with a very flat and high efficiency output throughout the audio response of the driver, extending very well up to he higher frequencies. This frequency response is rarely accomplished with permanent magnet driver.

  The frequency response clearly deteriorating as the power to the coil is reduced specially at the top end of the frequency spectrum as shown in the orange colored curve, the response is very similar with 28 to 30 Volts applied, only showing a relatively small increase of output at the frequency extremes at higher Voltages.

The frequency response as shown in the graphic is very flat and smooth even using a 1/24 octave spectra instead of 1/3 as is usually measured for a smoother more forgiving curve.A very high sound pressure level of over 110db with only 1W (4V RMS with a 16 Ohms diaphragm)

   Measurements taken at the throat of the driver, with no horn, 1/24 octave spectra with a 16 Ohms diaphragm at 1 Watt (4.0 Volts RMS) sweep sinusoidal signal from 200HZ to 22,000 Hz., yielding a very high output.

No dividing network crossover was used (only for test purposes).

 

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