USERS MANUAL ? 2004, PreSonus Audio Electronics, Incorporated. All rights reserved.
PreSonus Limited Warranty PreSonus Audio Electronics Inc. warrants this product to be free of defects in material and workmanship for a period of one year from the date of original retail purchase. This warranty is enforceable only by the original retail purchaser. To be protected by this warranty, the purchaser must complete and return the enclosed warranty card within 14 days of purchase.
1 Overview 1.1 Introduction 1.2 Features 2 2.1 2.2 2.3 3 Controls & Connections Front Panel Basic Layout Preamplifier Section Back Panel Basic Layout Operation 3.1 Dynamic Microphones 3.2 Phantom Powered Microphones 3.3 Instrument Input 3.4 Some Thoughts on Vacuum Tubes 4 Technical 4.
1 . 1 I N T R O D U C T I O N Thank you for purchasing the PreSonus BLUETUBE DP two channel Dual Path mic/instrument preamplifier. This preamp was designed using state of the art components to deliver crystal clear audio for an infinite period of time. We believe the BLUETUBE DP to be an exceptional sounding unit and an exceptional value. Please contact us at 1-800-750-0323 with your questions or comments regarding this product.
noise performance and wide dynamic control. This gives the BLUETUBE DP the ability to boost your signal without increasing unwanted background noise. ? Phantom Power. Each channel of your BLUETUBE DP has 48V phantom power available. When the phantom power switch is engaged on either channel, power is supplied at a constant rate to that channel. This assures optimum performance of your condenser microphone(s) and that the signal will be free of distortion due to insufficient power. ? Polarity Reversal.
input. ? Tube Drive. The BLUETUBE DP provides a Tube Drive potentiometer on each channel for controlling the amount of saturation produced by the 12AX7 vacuum tube. Greater levels of tube saturation give the signal greater warmth and a richer sound. This works equally well on mics and instruments.
2 . 1 F R O N T P A N E L BASIC LAYOUT The front panel of the BLUETUBE DP has analog VU meters for channel 1 and 2 to the far left and far right respectively, which measure the input level. VU stands for ‘volume unit’, which is an average measurement of the input signal level. This means that not all transients will be displayed by the VU meter.
Phantom Power is available to each channel input of the BLUETUBE DP. The 48 volts is supplied by way of the XLR connector for condenser mics and any other devices requiring continuous power through the XLR input. This power is supplied at a constant level allowing use of both inputs simultaneously. PIN 1 GND PIN 2 +48v PIN 3 +48v XLR connector wiring for Phantom Power Polarity Reversal Switch. This allows the user to invert the polarity of the XLR connector by switching pins two and three.
signal that you’ll need. Tube Drive. The BLUETUBE DP Tube Drive control increases the amount of saturation produced by the 12AX7 vacuum tube. The Tube Drive can be turned on or off, and the effect achieved by this procedure can be subtle to extreme, depending on the setting being used. A “warming up” of the sound can be noticed with lower Tube Drive settings. This desirable effect is especially good for microphones and electric bass guitar, resulting in a warmer, “rounder” sound.
2 . 3 BACK PANEL BASIC LA YOUT PIN 1 GND PIN 2 High (+) PIN 3 Low (-) Cable Wiring Diagram for Input and Output XLR The Output XLR Connector is servo balanced and operates at +4dBu. TIP High (+) SLEEVE GND (-) Cable Wiring Diagram for Input and Output ¼” TS Plug The Output ¼” TS Connector is unbalanced and operates at -10dBv.
3 . 1 D Y N A M I C M I C R O P H O NES Dynamic microphones are characterized by lower output levels. Hence, more gain is needed to amplify a dynamic microphone to operating level. Occasionally it is necessary to engage the –20dB pad to the microphone to avoid distortion (e.g. when recording percussion). Do not use phantom power when using dynamic microphones. 3 .
3 . 4 S O M E T H O U G H T S O N V A C U U M T U B E S The BLUETUBE DP comes supplied with a 12AX7 vacuum tube that meets or exceeds the stated performance criteria for the unit. We expect some owners of the BLUETUBE DP will try different tubes to investigate the various performance possibilities they might provide. Tube replacement can be easily accomplished by first unplugging the unit from the electrical outlet and removing the screws which attach the top to the chassis.
4.1 T ECHNICAL SPECIFICATI O N S BLUETUBE DP Technical Specifications: Number of Channels Two Performance THD + Noise (Unweighted) 0.005%@0dBTubeDrive 10% @ 100% Tube Drive Noise Floor Signal to Noise Power Supply Rejection Amplifier Type -94dBu >90dB >98dB Dual Path Input Connectors Input Impedance, XLR Input Impedance, High Z ¼” Neutrik? Combo 1.
