DigiTech VTP1 Owner's Manual - Page 4

Browse online or download pdf Owner's Manual for Music Equipment DigiTech VTP1. DigiTech VTP1 15 pages. Dual vacuum-tube preamp/eq/converter

Print Page

Introduction

Thank you for purchasing the Digitech VTP-1 vacuum tube preamplifier. This product was devel-

oped to help you improve the sound of your digital recording, analog recording, and live perfor-

mance.

The VTP-1 offers a better alternative to using the average quality microphone preamps found in the

typical multi-input console. For economic reasons, these console preamps are typically of lower

quality than a single, dedicated unit. You can use the VTP-1 to get your basic tracks sounding great

and then you can run the finished mix through it for final "tube" treatment and equalization.

The VTP-1's preamplifier circuit is a hybrid design consisting of a high-voltage class A vacuum tube

amplification stage, coupled with an ultralow noise, low distortion solid-state driver stage. In the

VTP-1's base configuration, the solid-state driver stage provides 40 dB of gain to the microphone

inputs. With the optional input transformers installed, the driver stage gain is reduced to 20 dB,

with 20 dB of virtually "noiseless" self-gain provided by the transformers.

Please contact DOD Electronics at 801-566-8800 to order the transformer installation

instructions and parts kit.

The vacuum tube amplification stage is a classic, high plate-voltage design utilizing a pure class A

topology. A parallel-triode arrangement is employed, in addition to a fully-regulated 235V plate

supply to maximize signal-to-noise performance and transient response. Only premium-grade

12AX7A vacuum tubes are used in the VTP-1 which are hand-tested and graded specifically for the

VTP-1 by Audio Glassic in the USA.

Precision 1% metal-film resistors are used throughout the audio path to ensure performance stability

and low noise. In addition to precision resistors, all filter and equalization circuits utilize high quali-

ty plastic-film capacitors to maintain spectral accuracy and minimize the long-term effects of com-

ponent drift. To ensure years of trouble-free operation, each VTP-1 must pass a rigorous set of per-

formance tests and a 24-hour burn-in period before it is shipped from the factory

Features

• Low noise, pure Class A vacuum tube preamplifier stage

• Line level input that accepts -10 dBv and +4 dBu signals

• Single vacuum tube per channel with adjustable gain and trim controls

• Four band semi-parametric equalization with EQ bypass switch

• 75 Hz low cut filter with steep 12 dB/octave

• 18 bit digital output to AES/EBU and S/PDIF digital protocols

• XLR and TRS 1/4" balanced analog inputs and outputs

• Post EQ insert loop

• Combined VU metering and multisource peak indication

• Switches for 48 volt phantom power, phase reversal, 20 dB gain pad and input select

•••