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Summary of Contents for D.W. Fearn VNE
- Page 1 HAZELRIGG INDUSTRIES Vacuum Tube Compression Amplifier Operating Instructions...
- Page 2 How to Contact us: Telephone: 567-DWFEARN (567-393-3276) Shipping Address: 124 Tartan Terrace Chalfont, PA 18914 U.S.A. e-mail: support@hazelriggindustries.com www.dwfearn.com VNE Vacuum Tube Compression Amplifier HAZELRIGG INDUSTRIES...
- Page 3 124 Tartan Terrace Chalfont, PA, U.S.A. Tel: 567-393-3276 Certificate of RoHS Compliance D.W. Fearn / Hazelrigg Industries is committed to manufacturing products that are fully- compliant with the EU RoHS Directive. The following products are compliant: D. W. Fearn VT-1, VT-2...
- Page 4 VNE Vacuum Tube Compression Amplifier Final Test Report Serial Number Mains Voltage: Date Tested by THD+Noise: 20 cps 200 cps 2 kc/s 20 kc/s Operational Tests: Compression Range Attack Release GR Meter Listening Test VNE Vacuum Tube Compression Amplifier HAZELRIGG INDUSTRIES...
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Page 5: Table Of Contents
Table of Contents Warranty....................6 Specifications....................7 Description....................8 Installation....................9 Operation....................12 Theory......................17 Maintenance ....................20 List of Illustrations Rear Panel Connections................11 Front Panel Controls and Connections.............13 VNE Vacuum Tube Compression Amplifier HAZELRIGG INDUSTRIES... -
Page 6: Warranty
This warranty does not extend to any VNE that has been damaged or rendered defective as a result of accident, misuse, or abuse; by the use of parts not manufactured or supplied by D.W. -
Page 7: Specifications
0 to 20dB Power Requirements 120 or 220 VAC 50/60Hz, 25 W Dimensions 19” (48.26cm) W 3.5” (13.34cm) H 14” (22.86cm) D Weight 12.5 lbs. (5.66 kg) Shipping weight 16 lbs. (7.26 kg) VNE Vacuum Tube Compression Amplifier HAZELRIGG INDUSTRIES... -
Page 8: Description
The input and output is at line level. The VNE is an adaptation of the D.W. Fearn VT-7 stereo tube compressor. The audio path is entirely Class-A triode vacuum tubes, similar to classic designs but updated with improved modern passive components and computer-aided circuit optimization. -
Page 9: Installation
In tight equipment enclosures, be sure there is adequate air flow. Forced air cooling will benefit all your equipment. The VNE can also be used without a rack, placed on a table, counter, or even on the floor. Optional rubber feet are available, when requested at the time of the order. - Page 10 Power The VNE is designed to operate from 120 or 220-240 volt, 50/60 Hz power. The unit will be shipped wired for the voltage specified in the order, but may be changed in the field if necessary (Call the factory for detailed instructions). The ground pin of the power cord is internally connected to the chassis.
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Page 11: Rear Panel Connections
See Figure 1. Gold-plated XLR connectors are used for inputs and outputs. The input connectors are female and the outputs male. Figure 1. The VNE rear panel connectors All connectors are wired according to AES standard: pin 1 is ground (shield), pin 2 is “high” or “+,”... -
Page 12: Operation
In modern studio equipment, bridging line inputs are universal. If the device being fed by the VNE has an input termination switch, that switch should be in the “off” position. -
Page 13: Front Panel Controls And Connections
The Threshold control adjusts the point where compression begins. With the control all the way down, there is no compression and the VNE operates as a straight amplifier. As the control is turned clockwise, the amount of compression increases. This can be monitored on the Gain Reduction meter, or by ear. - Page 14 Attack (5) This control adjusts the time it takes the VNE gain reduction circuitry to react to a signal. It might seem that the faster the attack time, the better, but very fast attack times will result in significant distortion on material with a lot of low frequency content (this is true of all compressors).
- Page 15 Power switch and indicator (8 & 9) Primary power is applied to the VNE circuits when the Power switch (9) is in the up position. The red pilot lamp (8) indicates that the unit is on. It take about twenty seconds for the compressor to start working, but it is suggested that you turn on the power at least five minutes prior to use.
- Page 16 SUGGESTIONS: You have chosen to use the VNE because of the superior sound it provides. To gain the maximum benefit from your investment, it is important that you hook up the VNE so that other factors do not adversely affect the sound quality.
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Page 17: Theory
Output Stage The output stage operates as a cathode follower, presenting a comparatively low output impedance (approximately 450 ohms). The cathode output is coupled through a polypropylene capacitor to the Pulse Width Modulator board. VNE Vacuum Tube Compression Amplifier HAZELRIGG INDUSTRIES... - Page 18 VNE. The power transformer is a toroidal unit custom-made for the VNE and has primary taps for 115 and 220-240 volt operation. A switch on the rear makes it quick and easy to go between voltages. Be sure to also change the fuse to the appropriate value.
- Page 19 Modulator. B+ supply Two separate regulated voltages are required for the plates of the VNE. The B+ is filtered with long-life, low-leakage computer-grade filter capacitors before being regulated and extensively bypassed and decoupled. The negative side of the supply is grounded.
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Page 20: Maintenance
Vacuum Tubes Four 6072A tubes are used in the VNE. There can be as much as a 15 dB difference in noise level among an assortment of tubes, and the tubes used in the first position should be carefully chosen to maintain low noise. - Page 21 Call first, however, for shipping information. WARRANTY REPAIR If the VNE should develop a problem during the 7-year warranty period, call the factory for return shipping instructions. We will repair and return your VNE quickly. Note that the warranty does not cover vacuum tubes, which must be periodically replaced.
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