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1、PROTECTION POWER CLIPPING CH1 LEVEL BRIDGED MONO POWER AMPLIFIER RB-951 MkII CH2 LEVEL Owners Manual RB-951 MkII Stereo Power Amplifier RadioFans.CN 收音机爱 好者资料库 2RB-951 MkII Stereo Power Amplifier 1: Controls, Connections, the CH2 level control changes the right channel. To adjust these controls, use
2、 a small, flat-blade screwdriver. Turn the control clockwise to in- crease gain. Turn counterclockwise to reduce gain. NOTE: These controls may be disabled by re- setting an internal jumper. 9 Clipping Indicators Two front panel LEDs (one for each channel) flash to indicate when the amplifier is “cl
3、ip- ping” or being asked to deliver more output current than it is capable of delivering. Clip- ping will cause distortion levels to increase. Occasional brief clipping on the loudest mu- sical passages is acceptable. However, sus- tained or frequent clipping is one of the most common causes of spea
4、ker damage and should be avoided. Should this occur, either reduce the overall gain of the system by turning down the master volume control on your preamp. Alternatively, you may wish to permanently reduce the gain of the amplifier using the front panel level controls (see previous section). Signal
5、Output Link This pair of RCA connections can be used to pass the unprocessed input signals to another audio component, for example to “daisy-chain” an additional amplifier to drive a second set of speakers. Any INPUT SIGNAL is also avail- able at these LINK outputs. Speakers The RB-951MkII has two p
6、air of speaker con- nectors, one pair for each channel. These can be used to connect two loudspeakers in Ste- reo mode, or to connect one loudspeaker in Bridged Mono mode. Speaker Selection The nominal impedance of the loudspeaker(s) connected to the RB-951MkII in the various operating modes should
7、be: Stereo mode: minimum 4 ohms Bridged Mono mode: minimum 8 ohms Parallel Mono mode: minimum 2 ohms When driving multiple pairs of speakers con- nected in parallel, the effective impedance the amplifier sees is cut in half. For example, when driving two pair of 8 ohm speakers, the am- plifier sees
8、a 4 ohm load. When driving mul- tiple speakers in parallel, select speakers with a nominal impedance of 8 ohms or higher. Speaker Wire Selection Use insulated two-conductor stranded wire to connect the RB-951MkII to the speakers. The size and quality of the wire can have an au- dible effect on the p
9、erformance of the system. Standard speaker wire will work, but can re- sult in lower output or diminished bass response, particularly over longer distances. In general, heavier wire will improve the sound. For best performance, you may want to consider spe- cial high-quality speaker cables. Your aut
10、ho- rized Rotel dealer can help in the selection of appropriate cables for your system. Polarity and Phasing The polarity the positive/negative orienta- tion of the connections for every speaker and amplifier connection must be consistent so all the speakers will be in phase. If the polarity of one
11、connection is mistakenly reversed, bass output will be very weak and stereo imaging degraded. All wire is marked so you can iden- tify the two conductors. There may be ribs or a stripe on the insulation of one conductor. The wire may have clear insulation with dif- ferent color conductors (copper an
12、d silver). There may be polarity indications printed on the insulation. Identify the positive and nega- tive conductors and be consistent with every speaker and amplifier connection. Speaker Connections See Figures 2 & 3 The RB-951MkII has one pair of color coded connections per channel. Labels abov
13、e the connectors show the proper connections for Stereo mode. Labels below show the proper connections for Bridged Mono mode. These speaker connectors accept bare wire, connector lugs, or “banana” type connectors (except in the European Community countries where their use is not permitted). Route th
14、e wires from the RB-951MkII to the speakers. Give yourself enough slack so you can move the components enough to allow access to the speaker connectors. If you are using banana plugs, connect them to the wires and then plug into the backs of the speaker connectors. The collars of the speaker connect
15、ors should be screwed in all the way (clockwise). If you are using terminal lugs, connect them to the wires. If you are attaching bare wires directly to the speaker connectors, separate the wire conductors and strip back the insu- lation from the end of each conductor. Be careful not to cut into the
16、 wire strands. Unscrew (turn counterclockwise) the speaker connector col- lar. Place the connector lug around the shaft, or insert the bundled wire into the hole in the shaft. Turn the collars clockwise to clamp the connector lug or wire firmly in place. NOTE: Be sure there are no loose wire strands
17、 that could touch adjacent wires or connec- tors. In Stereo mode: Connect the left speaker to the pair of speaker connectors labeled CH1. Connect the right speaker to the speaker con- nectors labeled CH2. Follow the labels printed above the connectors and make sure the BRIDGE MODE switch is set to t
18、he NORMAL STEREO position. (See Figure 2) In Bridged Mono mode: Connect the posi- tive terminal of the speaker to the speaker con- nector labeled BRIDGE +. Connect the nega- tive terminal of the speaker to the speaker con- nector labeled BRIDGE . Follow the labels printed below the connectors and ma
19、ke sure the BRIDGE switch is set to the BRIDGE MONO position. (See Figure 3) In Parallel Mono mode: Connect the speak- ers in the same fashion as in the Stereo mode. You can use the connectors for either chan- nel or both the same output signal is present at both pair of connectors. (See Figure 2) E
20、nglish 10RB-951 MkII Stereo Power Amplifier Internal Jumper Settings for Custom Installation (see figure 1) There are internal jumpers that can be used to disable the front panel level controls, to select one of two input sensitivity settings, and to engage the special Parallel Mono mode for driving
21、 low impedance speaker combinations in custom installations. WARNING: Removing the top cover of the am- plifier to access the jumpers may expose you to potentially dangerous voltages. These set- tings should only be made by a qualified tech- nician. The AC power cord must be removed from the amplifi
22、er before the top cover is re- moved. After removing the top cover, the jumper blocks can be found on the circuit board as shown in Figure 1. Each jumper block has a printed identification number. The function, ID num- bers, and settings for each jumper block are provided below. To change the settin
23、g, place the jumper on the appropriate pins as indi- cated. Bypassing the Variable Level Controls (S603 and S604) The front panel Level Controls allow you to adjust the input gain for each channel of the amplifier. These level controls can by bypassed by changing the jumper position on jumper blocks
24、 S603 (for CH 1) and S604 (for CH2). To disable the variable level controls: place a jumper across pins 2 and 3 on jumper block S603 and across pins 1 and 2 on jumper block S604. To enable the variable level controls: place a jumper across pins 1 and 2 on jumper block S603 and across pins 2 and 3 on
25、 jumper block S604. Input Sensitivity (S605 and S606) Jumper blocks S605 and S606 are used to set the input sensitivity of the amplifier. For high sensitivity (0.775v input for rated power): place the jumpers across pins 1 and 2 on jumper blocks S605 and S606. For low sensitivity (1.5v input for rat
26、ed power): place the jumpers across pins 2 and 3 on jumper blocks S605 and S606. Selecting Parallel Mono Mode (S602 and P1/P3) As described earlier in this manual, the two most common operating configurations for the RB-951MkII (Stereo mode and Bridged Mono mode) are selectable with a back panel swi
27、tch and require no internal changes. The third configuration, Parallel Mono mode, allows both channels of the amplifier to be com- bined in parallel. This mode is useful for driv- ing a low impedance speaker load such as driving multiple speakers in a custom instal- lation. This Parallel Mono mode c
28、an be selected only by setting internal jumpers (jumper block S602) and changing a buss wire connection (con- nectors P1and P2). NOTE: it is essential that Parallel Mono mode not be engaged at the same time as Stereo mode. This will blow the internal rail fuses. Make sure that you follow all of the
29、instruc- tions below carefully. To convert to Parallel Mono mode: 1. Place the jumper across pins 1 and 2 on jumper block S602. 2. Locate the buss wire linking the P2 connector to the P3 connector. Remove the wire from P3 and move it to the adjacent P1 connector. For Parallel Mono mode, the buss wir
30、e must link P2 to P1. To return to normal configuration (Ste- reo or Bridged Mono modes): 1. Place the jumper across pins 2 and 3 on jumper block S602. 2. Locate the buss wire linking the P2 connector to the P1 connector. Remove the wire from P1 and move it to the adjacent P3 connector. For normal m
31、ode, the buss wire must link P2 to P3. Troubleshooting Most difficulties in audio systems are the re- sult of poor or wrong connections, or improper control settings. If you encounter problems, isolate the area of the difficulty, check the control settings, determine the cause of the fault and make
32、the necessary changes. If you are un- able to get sound from the RB-951MkII, refer to the suggestions for the following conditions: Front Panel Power Indicator Is Not Lit No main power to the RB-951MkII. Check AC power connections at the amplifier and the AC outlet. Check the front panel power switc
33、h. Make sure that it is set to the ON position. If using signal sensing auto power-on, make sure that a signal is present at the inputs. If using 12V trigger power-on, make sure that a trig- ger signal is present at rear panel screw ter- minals. No Sound If the amp is getting AC power, but is produc
34、ing no sound, check the PROTECTION INDICA- TORS on the front panel. If lit, see below. If not, check all of your connections and con- trol settings on associated components. Make sure that your input connections and speaker connections match your selected stereo/mono configuration. Protection Indica
35、tor Is Lit The front panel PROTECTION INDICATORS light when the RB-951MkII protection circuits have shut off the amplifier. Typically, this oc- curs only when the ventilation openings are blocked, when there is faulty speaker wiring, or after a period of extreme use. Turn off the system and wait for
36、 the amp to cool. Then push the front panel power switch in and out to re- set the protection devices. If the problem is not corrected or reoccurs, there is a problem with the system or the amplifier itself. 11English Specifications Continuous Power Output Stereo Mode (20-20 kHz, 0.03% THD) 50 watts
37、/ch into 8 ohms Continuous Power Output Bridged Mono Mode (20-20 kHz, 0.1% THD) 150 watts/ch into 8 ohms Total Harmonic Distortion (20Hz-20kHz, 8 ohms) 0.03% Intermodulation Distortion (60 Hz : 7 kHz, 4:1) 0.03% Frequency Response (1 dB) 15Hz-100kHz Damping Factor (20-20,000 Hz, 8 ohms) 280 Speaker
38、Impedance (combined load) Stereo mode: 4 ohms minimum Bridged Mono mode: 8 ohms minimum Parallel Mono mode: 2 ohms minimum Signal to Noise Ratio (IHF A network) 116 dB Input Impedance 32 k Ohms Input Sensitivity 1.5 volt (low setting) 0.775 volt (high setting) Auto Turn On Threshold Level (if activa
39、ted) 10 mV input signal Auto Turn Off Delay Time (if activated) 5 minutes with no signal Power Requirements USA: 115 Volts, 60 Hz Europe: 230 Volts, 50 Hz Power Consumption 200 Watts Dimensions (W x H x D) 440 x 92 x 334 mm 173/8 x 35/8 x 131/4 in Weight (net) 6.8 kg, 15 lb. All specifications are a
40、ccurate at the time of printing. Rotel reserves the right to make improvements without notice. The Rotel Co. Ltd. 10-10 Shinsen-Cho Shibuya-Ku Tokyo 150-0045 Japan Phone: +81 3-5458-5325 Fax: +81 3-5458-5310 Rotel of America 54 Concord Street North Reading, MA 01864-2699 USA Phone: +1 978-664-3820 Fax: +1 978-664-4109 Rotel Europe Meadow Road Worthing, West Sussex BN11 2RX England Phone: +44 (0)1903 524 813 Fax: +44 (0)1903 524 831 Rotel Deutschland Kleine Heide 12 D-33790 Halle/Westf. Germany Phone: +49 05201-87170 Fax: +49 05201-73370 082 OMRB-951MkII 113099
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