VNE Vacuum Tube Compression Amplifier
HAZELRIGG INDUSTRIES
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. The
tubes are often noisy until all the internal elements reach a stable operating temperature.
Initial Set-Up
The VNE should be installed as detailed in the Installation section. With the outputs connected to
an appropriate destination (typically to audio recorder inputs or as a mixer insert), configure the
studio to monitor the VNE output. Apply power and wait about twenty seconds for the tube
filaments to get up to temperature. Check for hum, buzz, or other noise. For the first few minutes
after a cold start it is not unusual for the VNE to produce hiss, pops, and micro- phonic “clanks”
as the internal elements of the tubes expand from the heat. Correct any ground loop problems
before proceeding.
The controls should be set as follows. The numbers refer to Figure 2 on page 12.
• Power(9).............................On
• Threshold(1).......................9 o’clock
• Input selector(2)……..…..IN
• Attack(5)............................1 o’clock
• Release(6)..........................9 o’clock
• Gain(7)..............................9 o’clock
The best indication of proper operation of the VNE is how it sounds. This compressor has a wide
operating range and many different settings can provide a wide variety of effects.
Be certain that the output level of the VNE is appropriate for the device connected to the output.
+4 dBm is the accepted standard level for all professional recording equipment. Some older
equipment may be designed for 0 dBm or +8 dBm, either of which can be easily accommodated
by the VNE.
Semi-professional equipment frequently uses a reference level of -10 dB (roughly 14 dB lower
than pro equipment).