Herron VTPH Owners manual

Owner’s Manual

Please read the Owner’s Manual completely BEFORE operating the unit.

VTPH-1

VTPH-1

Vacuum Tube

Phono Preamplifier

Vacuum Tube

Phono Preamplifier

Owner’s Manual

Owner’s Manual

Please read the Owner’s Manual completely BEFORE operating the unit.

Owner’s Manual

Please read the Owner’s Manual completely BEFORE operating the unit.

Thank you for your investment in
the Herron Audio Vacuum Tube
Phono Preamplifier, a masterpiece
of high-precision analog audio play­back equipment. It is designed to be
the finest product of its type avail­able. The care in engineering and
manufacturing of this product
anticipates a lifetime of musical
enjoyment.

The Herron Phono Preamplifier
was created to address the retrieval
of musical information from vinyl
LPs better than any other unit avail­able at any price. The original design
was only intended for use by a few
dedicated music lovers in their cut­ting edge audio systems. The design
was so good, and demand so high,
that the unit was refined and engi­neered to meet the requirements for
a more durable unit manufactured
in larger quantities. In the process,
important refinements were devel­oped and discoveries were made
about tolerances and the threshold
of human hearing limits.

This product is engineered to be
user friendly, and overcomes the
fears that many have expressed
concerning the use of vacuum tubes
in their systems. Its limited produc-

tion ensures that the components in
each unit are matched to the highest
standards in the industry. Manufac­turing of the unit is performed under
the tightest of quality controls.
Components are hand-matched to
exacting standards—far better than
the normal 5% tolerances—to ensure
identical unit-to-unit performance.
For example, capacitors in the RIAA
equalization stage are hand matched
to tolerances of less than 0.1%
variation from the design of the
prototype. Tubes are burned in,
bench tested, and hand-matched
both across units and to the original
design. These techniques ensure
that each unit performs to the high
standards established in the develop­ment of the original prototypes. This
costly process is reflected in the
unprecedented performance and
lack of unit-to-unit variations of
Herron Audio components.

The special power supply in all
Herron Audio products reflects the
engineering innovation that allows
the Herron Phono Preamplifier to
provide the highest musical satisfac­tion without the artifacts produced
by most other tube-based compo­nents. This power supply provides a

three

Welcome!

Welcome!

Herron Audio Vacuum Tube Phono Preamplifier

two

Table of Contents

3 Introduction

5 Models

5 Design Considerations

6 Front Panel Information

7 Rear Panel Information

8 Installation and Operation

9 Cartridge Loading

10 Power Line Polarity

10 Optimum Performance

11 Changing Tubes

12 Technical Specifications

© 1998 Herron Audio
Division of Herron Engineering, Inc.
12685 Dorsett Road
Suite 138
St. Louis, MO 63043

314.434.5416

314.434.6629 fax

Owner’s Manual

Please read the Owner’s Manual completely BEFORE operating the unit.

Owner’s Manual

Please read the Owner’s Manual completely BEFORE operating the unit.

five

VTPH-1MM moving magnet version (use with cartridges above

1 millivolt output)

VTPH-1MC moving coil version (same as the MM version with an addi-

tional FET front end amplifier)

Design Considerations

• All-tube signal path (moving magnet version)

• Passive RIAA equalization for accurate phase and amplitude response

• Star grounding for low interference susceptibility and clean signal path

• Zero feedback—no feedback loops in the audio circuitry

• Low noise

• No switches in the signal path

• High input signal capacity without overload; see technical specifications

• Gold plated TIFF RCA and ground connectors

• Audio path capacitors are polypropylene and polystyrene

• Hand-picked components for accurate response

• Automatic muting at startup and shutdown

• 78,000 µF of power supply energy storage capacitance

• 4 levels of high voltage regulation

• Regulated soft-start DC filament supply

• Regulated tube bias supply

• Toroidal power transformer

• Rugged—0.10" thick aluminum chassis with 0.25" thick faceplate

• Reversing power line (AC) polarity switch for minimizing line-to-chassis
reactive currents and noise pickup

• Controlled warm-up of tube filaments and high voltage for extended
tube life

• Low plate operating currents for extended tube life and cool operation

• Front panel indicators for power, filament voltage, and output (mute release)

• Each unit is given a 48-hour burn-in, including rigorous bench and
listening tests

VTPH-1 Models

VTPH-1 Models

rigid voltage source to the tubes,
producing remarkable resolution of
musical events in time and sound
stage.

The circuit board layout was
engineered with all of its electrical
properties considered, in order to
achieve fine audio performance
with greater consistency than hand
wiring. Compromise was not an
option.

The unique design of the Herron
Phono Preamplifier, along with its
conservative design and operating
parameters, means that owners can
expect the industry’s highest level of
performance to be maintained over
the extended life of the unit.

Operating the Herron Phono
Preamplifier is easy and straight­forward. The unit has been designed
to be exquisitely simple and user
friendly, with its operational readi­ness easily monitored.

During the manufacturing
process, every unit is subjected to
a battery of quality control checks.
Each unit is run through a full forty­eight hour burn-in, and then
measurements are made to make
sure that it is functioning correctly.
Last and most importantly, careful
listening tests are made in compari­son to a reference unit, to make sure
each Phono Preamplifier performs
up to the strictest Herron Audio
standards.

The staff of Herron Audio are
audiophiles who regard the high­quality reproduction of the
performance of music as one of the
finest pursuits in the engineering
arts. We at Herron Audio believe in
the pursuit of audio perfection. We
hope you enjoy the fruits of our
efforts. If you have any comments,
suggestions, or questions, please
contact us at 314-434-5416.

Herron Audio Vacuum Tube Phono Preamplifier

four