User manual ROLLS MA251

[. . . ] WARNING: THE MINIMUM SPEAKER IMPEDANCE IS 4 OHMS EACH. IF YOU CONNECT AND USE THE MA251 WITH A LOWER SPEAKER IMPEDANCE THAN LISTED ABOVE YOU WILL DAMAGE THE UNIT AND POSSIBLY OTHER EQUIPMENT THAT IS CONNECTED TO THE MA251. MA251 5 + 5 watt Mixer/Amplifier MADE IN USA www. rolls. com MA251 0 10 0 10 0 10 0 10 SPECIFICATIONS: Line Input Impedance: Power Output: Voltage Gain: Maximum Supply Voltage: THD: EIN: Efficiency: Input Sensitivity: Bandwidth: +Size: Weight: 10K Ohms Line 600 Ohms Mic. 5 Watts X 2 (4 Ohms) 55 dB Mic 30 dB Line 24 VDC . 05% typical 3 mV 85% 28 mV 20Hz - 25 kHz +/- 3dB 6. 75" x 3. 5" x 1. 5" 1 lb. 5 + 5 WATT MIX/AMP CLASS AMP CH 4 INPUT CH 4 LEVEL CH 3 LEVEL CH 2 LEVEL CH 1 LEVEL CH 2 MONO INPUT SPEAKER OUTPUTS PS12 OFF - ON PHANTOM POWER CH 1 INPUT CH 2 INPUT CH 3 INPUT LINE OUT MUTE + RIGHT - - + LEFT · RCA Inputs, XLR Mic with Phantom Power · Volume controls for each Channel · Low noise, efficient operation · Small compact size · Class D high efficiency amp The MA251 is a very compact 5 + 5 watt high efficiency amp with a four channel stereo mixer built in. [. . . ] All inputs except CH 1 microphone and Ch MONO input are stereo. Outputs for Speaker and Line are true stereo. NOTE: THIS MANUAL ASSUMES THE USER HAS A WORKING KNOWLEDGE OF AUDIO ELECTRONICS, BALANCED AND UNBALANCED CONNECTIONS, AND PROPER SIGNAL LEVEL SETTING. Unpack and inspect the MA251 box and package. If obvious physical damage is noticed, contact the carrier immediately to make a damage claim. We suggest saving the shipping carton and packing materials for safely transporting the unit in the future. Please visit our web site at www. rolls. com and click on the Register Your Warranty Here button. CHANNEL DESCRIPTION CH 1 INPUT: XLR jack for connection to a microphone. Switchable phantom power as labeled on unit. CH 2 INPUTS: Stereo RCA and one mono RCA for connection to a signal source such as a CD player, cassette deck, tuner, etc. . PLEASE NOTE WITH A MONO INPUT AS WELL AS A STEREO INPUT, CHANNEL 2 AT CERTAIN IMPEDANCES ON THE STEREO INPUT YOU MAY EXPERIENCE CROSS TALK BETWEEN THE LEFT AND RIGHT. THIS IS NORMAL OPERATION AND SHOULD BE EXPECTED. CH 3 INPUT: Stereo RCA jack for connection to a signal source such as a CD player, cassette deck, tuner, etc. CH4 INPUT: For connection to a stereo 3. 5mm(1/8" jack). LINE OUT: Stereo RCA jacks for connection to a mixer or amplification device. CONNECTION / OPERATION To operate the MA251, properly connect cords from the sources to be mixed (mics, cassette decks, CD players etc. ) into the channel inputs. [. . . ] PHANTOM POWER SWITCH: Switches the Phantom Power on or off for a condenser mic on channel 1. 5 SCHEMATIC 22uH 22uH . 22uF 19 20 13 . 22uF C18 C21 18 12 PGNDL 11 BSR 16 17 PGNDR PVCCR PVCCL ROUT BSL AVCC AVCC LOUT 10 1 VCC VCLAMP BYPASS GAIN1 GAIN0 AGND AGND 1U C16 C17 VCC CH 2 MONO INPUT U2 4 5 6 7 8 9 2 14 SPEAKER OUTPUTS PS12 1U 15 3 MUTE LIN RIN SD TPA3122D2N MONO INPUT C24 . 1uF L1 L2 MUTE STEREO LINE OUTS R25 220K 120PF R10 100 U1B U1A V+ V+ 120PF R29 47K C31 4560 U3B 47K R30 P1A P100K X2 P1B P100K X2 P2A P100K X2 P2B P100K X2 P3A P100K X2 P3B P100K X2 1N4001 D2 C11 C12 C13 2200 2200 2200 2 3 R9 P4 P100K C7 1U R8 10K PHAN Q1 2N3904 +B R11 10K C3 1U 2 3 +B C28 47U 7 10K +B R5 6 5 332 R3 C1 10U C29 10U C32 120PF PHAN C2 10U C3010U R4 332 10K R19 1N4001 D4 PHANTOM R1 R2 SW2 3. 3K 3. 3K SPST R6 4. 7K www. rolls. com R7 4. 7K MADE IN USA R14 10K R15 10K 4 5 3 2 R17 R18 10K MA251 0 10 0 10 0 10 0 10 10K J5 XLR F PC CH 4 CH 3 CH2 CH 1 J4 J2B RCAX4 J2A RCAX4 J2D RCAX4 3. 5STJK J2C RCAX4 1 J1 6 3 5 + 5 WATT MIX/AMP CLASS AMP CH 4 INPUT CH 4 LEVEL CH 3 LEVEL CH 2 LEVEL CH 1 LEVEL JAPDC IN 12-24 VAC/VDC 1 2 1 5 4 2 2 3 1 D5 1N4001 3 2 2 5 2 5 2 5 R20 10K D3 1N4001 6 5 +B 4 6 1 3 4 6 1 4 3 4 1 6 1 3 8 4 CHANNEL VOLUME: Adjusts the level of signal from the Line Input to the Line out RCA's and Speaker outputs. 3. 5mm JACK: For connection to an ipod, MP3 player or computer TRS Stereo (left, right and ground) connection to channel 4 120PF R13 100 4560 C33 503 R22 18K R23 22K D1 FRONT PANEL 1 C6 47U R24 C15 10U 2 5 4 1 1K 47U C10 +B 4560 R12 100K R31 V+ U3A C4 100K 4560 C8 100 VCC LDRR 7 R21 4. 7K 1 3 6 OFF - ON PHANTOM POWER CH 1 INPUT CH 2 INPUT CH 3 INPUT LINE OUT RIGHT LEFT 1U 1U C5 C9 47U C14 MUTE R16 1K + + J3A RCAX4 - - J3D RCAX4 J3C RCAX4 J3B RCAX4 VCC Q3 2N3904 R26 10K Size: Title 3 8 Document Number: Rev: MA251. SCH A Rb Date: 21 October 2009 Sheet 1 of 1 C19 . 68uF C22 . 68uF MA251 CLASS MIXER AMPLIFIER 1 2 3 4 Rolls Corporation VCC C26 C27 . 1uF . 1uF VCC VCC C25 . 1uF 5968 S 350 W Murray Utah 84107 C20 1K R27 4. 7K R28 4. 7K C23 1K +--+ SPEAKER OUT J6 DESCRIPTION REAR PANEL PS12 MA251 CLASS AMP + BOTH + 5 WATT LEFT OUTPUTS MIX/AMP - MUST - RIGHT CH 4 3. 5mm STEREO BE USED + CH 4 LEVEL MONO INPUT MUTE CH 2 LINE OUT R L CH 3 LEVEL CH 3 INPUT L R CH 2 INPUT R CH 2 LEVEL L CH 1 INPUT CH 1 LEVEL ON - OFF PHANTOM POWER [. . . ]