VLC Microphone Preamplifier/EQ/DI
HAZELRIGG INDUSTRIES
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Remember that vacuum tubes may be quite hot during operation. Protect your fingers during tube
replacement. The preamplifier should be turned off before removing tubes. Allow at least one
minute for the filter capacitors to discharge before tube removal or insertion.
Tubes are made of glass and will break if dropped or even bumped in a critical area. Handle with
care.
Electrolytic Capacitors
Hazelrigg Industries products are designed and built to last for a long, long time, and it is possible
that some components (e.g. electrolytic capacitors) may reach the end of their life long before the
equipment becomes obsolete. The electrolytic capacitors used in the VLC typically will last at
least twenty years. If there is a measurable and/or audible increase in 120 cps noise, the filter
capacitors should be suspected. They should be replaced with new capacitors of equivalent
capacitance and voltage rating, and the replacements should be specified for a minimum ten-year
service life. Electrolytic capacitors are also used as plate and cathode decouplers. In choosing a
replacement, the same considerations as with the filter capacitors should be followed.
TROUBLESHOOTING
Most problems will be traced to defective vacuum tubes. However, if normal tests do not easily
reveal the problem, feel free to call the factory for assistance. If you lack access to a qualified
service technician with vacuum tube equipment repair experience, you may return the VLC to the
factory for repair. Call first, however, for shipping information.
WARRANTY
REPAIR
If the VLC should develop a problem during the 7-year warranty period, call the factory for
return shipping instructions. We will repair and return your VLC quickly. Note that the warranty
does not cover vacuum tubes, which must be periodically replaced.