User manual HAFLER SE120

[. . . ] Stereo Mode: This allows the right and left channels to reach their designated amplifier channels. Mono Mode: The SE1 20 can be operated in a bridged mode which drives both channels with the same signal and combines to deliver more than 150 watts into 8 ohms. This disables the right channel input and routes the signal through the left channel. Construction: The simplified construction of the SE120 improves reliability and results in consistent performance. [. . . ] Be sure the cables are not frayed or loosely connected to the plugs, and that the plug's outer shield connection is tight on the jack, to avoid hum. If you wish to install the SE120 more than a few feet from the preamplifier, the permissible cable length to avoid loss of high frequencies is determined by the preamplifier's output impedance and the internal capacitance of the cable. If the output impedance is 600 ohms or less, as with Hafler preamplifiers, and the cable capacitance is less than 50 picofarads per foot, up to 50- feet is acceptable. Ordinary stereo interconnecting cables often have higher capacitance, however, so a good quality low capacitance shielded wire should be used. When making long runs, keep the left and right cables close together, and avoid running them parallel to power wiring to reduce the likelihood of hum pickup. OUTPUT: The wires which connect the speakers to the amplifier should be of sufficient size to preserve the SEl2O's high Standard #18 gauge lamp cord damping factor. Standard #18 gauge lamp cord is satisfactory for up to 15 feet if your speakers are of 8 ohms or higher impedance. A heavier gauge (#16 or larger) wire should be #16 used with 4 ohm speakers or 8 ohm speakers at a greater distance. Special loudspeaker cables which have adequate thickness to accommodate long runs are usually available from audio dealers. The SEl2O's red and black outputs accept standard banana plug connectors, including the double ones with 3/4" spacing. These are the most convenient to use if you will be disconnecting the speakers occasionally. The terminals will also clamp a spade lug, or a bare wire through the hole in the center post. Be sure there are -3- CONVENTIONAL STEREO CONNECTIONS It is best to make all connections with the SE120 switched off. Each of the stereo speakers connects to one horizontal pair of red and black outputs, as identified left or right on back of the SE 120. The input signals connect to the corresponding input jacks, and the mono/stereo switch should be set to stereo. CONNECTIONS FOR MONOPHONIC OPERATION When you wish to drive a single loudspeaker with increased power capability, the SE120 can be operated in a bridged mode which drives both channels with the same signal and combines their output to deliver more than 120 watts into 16 ohms. In this arrangement, the speaker is connected only to the two red output terminals. The left red terminal is + and the right red terminal is the - connection. Set the Input Mode Selector switch to mono, and connect the input signal to the left channel input only. IMPORTANT NOTE: Never use a speaker with an impedance of less than 8 ohms when operating the SE120 in the bridged mono mode. The increased current could overheat the amplifier. TRANSISTOR VOLTAGE VALUESDC volts with respect to circuit ground, no signal applied. OPERATION The pilot lamp in the power switch will glow whenever power is applied to the SEl20. The SE 120 is equipped with a unique protection system that constantly monitors the temperature of the output devices and takes corrective action to prevent damage to the amplifier as a result of excessive overheating. Under most conditions, the SE120 heatsinks will dissipate the heat required to maintain safe operating temperatures, and the unit will play continuously. [. . . ] Polflropylene 3 3 0 p f d , 63Ov, 3%, D i i M i c a 100 tid, Non-Polar Radial 47 pfd, 65Cv. 10% Polypwylene 3pfd. 5Wv. D@)edMka O-W1 tid, 25Ov, 1% Pofypropytene 100 tid, 50~. 20% Pohr/ElecUolytic 0. 1 mfd, low, 20%$ PoIyeslef 0. 1 mfd, lUZv, m Pofyester 220 pfd, 75~. Pwene 100 tid, 5@u, 209& Polar/Electrolyric 0. 1 mfd, lWv, 209& Polyester 0. 1 mfd, 1Wv. [. . . ]