Speakers

Input Level Controls

Two controls on the front panel, one for each channel, provide input level adjust- ments. These allow you to adjust the gain of the ampliﬁer to match other components in the system. The L level control changes the gain of the left channel; the R level control changes the right channel.

To adjust these controls, use a small, ﬂat- blade screwdriver. Turn the control clock- wise to increase gain. Turn counterclockwise to reduce gain.

For easier adjustment, install the supplied vol- ume control knobs by gently pressing them onto the control shafts. Alternatively, you can prevent inadvertant adjustment by installing the supplied rubber plugs to conceal the vol- ume controls.

Signal Output Link

This pair of RCA connections can be used to pass the unprocessed input signals to anoth- er audio component, for example to “daisy- chain” an additional ampliﬁer to drive a sec- ond set of speakers. Any INPUT SIGNAL is also available at these LINK outputs.

The RKB-250 has two pair of speaker con- nectors, one pair for each channel.

Speaker Selection

The nominal impedance of the loudspeaker(s) connected to the RKB-250 should be a mini- mum of 4 ohms. When driving multiple pairs of speakers connected in parallel, the effec- tive impedance the ampliﬁer sees is cut in half. For example, when driving two pair of 8 ohm speakers, the ampliﬁer sees a 4 ohm load. When driving multiple speakers in par- allel, select speakers with a nominal imped- ance of 8 ohms or higher.

Speaker Wire Selection

Use insulated two-conductor stranded wire to connect the RKB-250 to the speakers. The size and quality of the wire can have an audible effect on the performance of the system. Standard speaker wire will work, but can result in lower output or diminished bass response, particularly over longer dis- tances. In general, heavier wire will improve the sound. For best performance, you may want to consider special high-quality speak- er cables. Your authorized Rotel dealer can help in the selection of appropriate cables for your system.

Polarity and Phasing

The polarity or positive/negative orientation of the connections for every speaker and am- pliﬁer connection must be consistent so all the speakers will be in phase. If the polarity of one connection is mistakenly reversed, bass output will be very weak and stereo imaging degraded. All speaker wire is marked so you can identify the two conductors. There may be ribs or a stripe on the insulation of one conductor. The wire may have clear insula- tion with different color conductors (copper and silver). There may be polarity indica- tions printed on the insulation. Identify the positive and negative conductors and be consistent with every speaker and ampliﬁer connection.

English

Speaker Connections

See Figure 2

The RKB-250 has one pair of color coded connections per channel. Labels above the connectors show the proper connections. 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 the wires from the RKB-250 to the speak- ers. Give yourself enough slack so you can move the components enough to allow ac- cess 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 connectors 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 di- rectly to the speaker connectors, separate the wire conductors and strip back the insulation from the end of each conductor. Be careful not to cut into the 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 that could touch adjacent wires or connec- tors.

Connect the left speaker to the pair of speaker connectors labeled LEFT. Connect the right speaker to the speaker connectors labeled RIGHT. Follow the labels printed above the connectors, Make sure that the positive ter- minal of the speaker is connected to the + terminal on the ampliﬁer. Make sure that the negative terminal of the speaker is connected to the – terminal of the ampliﬁer.