2 .
D E S C R I P T I O N
The Model VT-4 Vacuum Tube LC Equalizer is designed to provide recording
professionals with a sonically superior outboard processing device. It is typically
used in sound recording studios for modifying the frequency response character-
isics of an individual track. A pair of VT-4s can be used to process a stereo mix
with precise matching between units.
It is designed for use in the professional recording environment. It accepts all
standard low-impedance (nominally 600 ohm) line-level (nom4 dBm) sig-
nals. The output is line-level (+4 dBm) low-impedance, transformer-isolated and
designed to feed bridging inputs. It is built to sound great for a long time, with top
quality parts used throughout; all the transformers, inductors and many other com-
ponents are custom-made for the VT-4.
All power supplies are solid state and fully regulated. All rotary controls use
high-quality silver-contact switches for precise repeatability and matching
between units.
Much of the circuitry for the VT-4 is based on the highly-successful D.W. Fearn
VT-1 and VT-2 Vacuum Tube Microphone Preamplifiers. Since line-level signals
are utilized in the VT-4, Class-A Svetlana 6N1P dual triodes are used for all
amplifier stages. The input transformer, inductors in the passive equalization cir-
cuitry, and the output transformer are custom-made for us by Jensen Transformers
Inc.
The VT-4 is not mass-produced. Each one is hand-made and meticulously test-
ed and listened to before shipment to the customer.
The philosophy behind the VT-4 is: use only the best components in an opti-
mized circuit, and build it with pride and precision. The VT-4 is designed and built
to perform in your studio for decades to come.
