User manual NUMARK SA5500

[. . . ] The basic circuit has been kept as simple as possible to reduce the amount of components, thereby shortening the signal path, coloration and the chance of component failure. However, we opted to add what we regard as essential protection against overheating, short circuits and power on transients. An efficient heat dissipation system, comprising a high surface area heatsink coupled with one or two fans (depending on power rating of amp), ensures quiet and reliable cooling. The sound quality and sturdy construction of the Performance Series makes these amps ideal for a multitude of amplification tasks, from installations, mobile DJs, home studios, houses of worship and touring bands. [. . . ] Balanced Barrier Strip Inputs These connection points provide the best option for permanent or long term installation. Connections should be screwed down tightly to exclude oxygen, and care should be taken to avoid loose strands of wire that may cause short circuits. + - GND - + 8 ©1997 Numark Industries 3. ensure that there is only one input signal connected to channel 1 of the amplifier - channel 2 input must be vacant 4. verify operation at low gain, and then increase power to desired level, ensuring that the gain controls on each channel are set equally. IMPORTANT: NEVER SWITCH BETWEEN STEREO AND BRIDGED MONO OPERATION WHEN THE AMPLIFIER POWER IS ON. Limiter On / Off Switch In cases where a dedicated compressor / limit unit precedes the SA5500, some users may seek to disable the on board limiting. Sliding the switch to the off position removes the limiting from both channels of the amplifier. ©1997 Numark Industries 9 http://www. numark. com Audio Terms Gain This is the factor by which an input signal is amplified (increased) or attenuated (reduced) when passing through an amplifier. Gain is generally measured in decibels (dB) which is a logarithmic ratio of input to output. Unity or zero gain means that the signal comes out at the same level that it went in. With all this gain available, it may seem tempting to turn the amp up to full to get the loudest sound possible. And why is it that smaller amps have roughly the same gain even though they are less powerful?The answer is that an amp can only amplify up to a certain point, which depends on its power rating. The peaks of the signal are `clipped' as they exceed the limit. max+ Hum and Buzz Hum typically is a lower pitched sound of around 50 or 60Hz, depending on the AC supply. If the hum or buzz is very loud, this is generally caused by bad connections - check cables and plugs for faults. Lifting the Ground In other cases, a ground conflict between the chassis and the circuit ground can induce hum. This happens when a magnetic field induces a small voltage in the casing of the amp, making it slightly different in potential from the circuit ground. This hum sounds more subtle than it would be for a bad connection and is generally ignored. If your environment requires the highest quality sound, it may be eliminated by `lifting the ground'. This is accomplished by moving the back panel switch from the `ground on' position to the `floating' position. The electronic ground is then dependent on other connected components. For the best safety protection and protection of other components, it is strongly advised to keep the switch in the `ground on' position. Balanced Lines Power transformers and other devices which cause magnetic fields can induce hum in audio cables. This can be best combated by using balanced lines where inputs and outputs permit. [. . . ] Numark reserves the right to make changes or improvements in its products, during subsequent production, without incurring the obligation to install such changes or improvements on previously manufactured equipment. To place this warranty into effect, the enclosed WARRANTY REGISTRATION CARD must be returned to Numark Industries, LLC within thirty (30) days after date of purchase. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state. Some states do not allow the exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you. SERVICE INFORMATION In the unlikely event of a product defect or if your equipment ever needs factory service, please call (401) 946-4700 and request a return authorization number. [. . . ]