M-150 Monoblock Power Amplifier Owner’s Manual Rogue Audio, Inc.
TABLE OF CONTENTS 1) Introduction 2 2) Unpacking the M150 power amplifier 2 3) Connecting M150 to your system 3 4) Operation of the amplifier 4 5) Setting the tube bias 5 6) Troubleshooting 7 7) Registration card 8 8) Fuse values 8 9) Specifications 8 10) Warranty 9 1
INTRODUCTION Congratulations on your purchase decision! We at Rogue Audio truly believe that our amplifiers provide the “smartest” value in high-end audio. If you have never owned a vacuum tube amplifier you will be thrilled by the silky-smooth sound and incredible detail that only a tube amplifier can provide. And with the M150 Monoblock amplifier, you can be sure that you are getting the very best in tube amplification.
CONNECTING M150 TO YOUR SYSTEM Connecting M150 to the Loudspeakers: The rear panel has binding posts for both 4 and 8 ohm loudspeakers as shown in Figure 1. In general, if your speakers are rated at less than 6 ohms, use the 4 ohm taps and use the 8 ohm taps if they are 6 ohms or greater. CAUTION – Do not operate the amplifier unless it is connected to a loudspeaker. Connecting M150 to the preamplifier: There are two types of input connections on the rear panel of M150: 1) Fully balanced XLR type input.
Connecting M150 to the power outlet: Connect the IEC send of the detachable power cord provided to the amplifier, and plug the opposite end into corresponding outlet. It is recommended that both M150’s and your preamp are plugged into the same wall outlet if possible (perhaps using a power outlet strip). This is to avoid creating a ground loop. Amplifier Location: The M150 is an open tube design and depends on natural convection flow patterns for proper cooling.
Triode/Ultralinear switch: This switch is located on the back panel of the amp. See Figure 1. The output transformer of a tube amplifier acts as the electrical interface between the very different impedances of the loudspeaker and the tube circuitry. There are three fundamental ways that the output transformer can be connected to the tube circuit. 1) Tetrode or Pentode connection – In this configuration, the highest power level is achieved but at the expense of significantly higher distortion levels.
WARNING – There are dangerous and potentially lethal voltages inside this amplifier. Do not touch any part of the amplifier other than as described below. If you are uncertain about any of these instructions, please contact your dealer and have them bias the amplifier for you. Figure 2. Removable hatchplate 1) Allow the amplifier to warm up for at least 30 minutes.
7) Using the bias tool, slowly turn the screw on the potentiometer that is adjacent to the switch until the bias meter reads ~ 40 miliamps (mA). Turn the screw clockwise to lower the bias and counterclockwise to raise the bias. Note that there are two ends on the bias tool. Using the end with the recessed screwdriver will greatly facilitate this operation. KT88 (4) Output Tubes 12AX7 (1) Input Tube 12AU7 (2) Driver Tubes Potentiometers Switches Meter Figure 3.
TROUBLESHOOTING Speaker Hum – If hum can be heard from more than a few inches from the loudspeaker, there is probably a ground loop. If there is still hum, flip the grounded/ungrounded switch on the rear panel to ungrounded. If this fails to cure the hum, call customer service at Rogue Audio for further advice. Tube will not bias – If the meter provides a reading but the tube will not bias, the tube is probably bad. If no meter reading can be attained, check the fuse (1/4 Amp fast blow).
LIMITED WARRANTY Warranty Period This product has been manufactured under the highest standards of quality and workmanship. Rogue Audio Inc. (hereinafter “Rogue Audio”) warrants this product against defects in material or workmanship as follows: With the exception of vacuum tubes, Rogue Audio warrants to the original purchaser of this product all parts of this product against defects in material and workmanship for a period of three years from the date of retail purchase.
