User manual AKAI GX-365 SERVICE MANUAL

[. . . ] · The Model 3500 offers a number of additional advanced features, including front-panel compression and graphic equalizer LED indicators, effects send and return jacks, an effects send/return balance knob, and a direct output with ground lift and pre or post EQ selection. Both models are optimized for use with electric bass instruments, and the front panel controls in both models are virtually identical. You'll find either to be an excellent bass amplifier for live performance use in small and medium-size venues; in addition, the Model 3500's advanced features makes it ideal for use in recording environments. In these pages, you'll find a detailed description of the many features of the Model GX-365/3500 Bass Amplifiers, as well as a guided tour through their front and rear panels, step-by-step instructions for setting up and using each product, detailed discussions about equalization and compression, and full specifications. [. . . ] Contour High Pass control - This acts as a broad-band high frequency equalizer, providing 18 dB of boost or attenuation at 10 kHz. You should generally adjust this control (and the Contour Low Pass control, described in #9 above) prior to "fine-tuning" the system with the graphic equalizer (as described in #8 above). For more information, see the "About Equalization" section on pages 13 - 14 of this manual. For best signal-to-noise ratio, keep the output of your bass at or near maximum and adjust the amp's Master Volume to the desired level. Power switch - Use this to power the Model 3500 on or off. 10 Guided Tour - Model 3500 Rear Panel 1 3 4 5 8 9 Hartke Systems Distributed Exclusively by Samson Technologies Corp. Hicksville, New York 11802 115 SPEAKER OUTPUTS EFFECT SEND DIRECT OUT POST PRE NORMAL GND LIFT MODEL 3500 350 WATTS 8 = 240 WATTS 4 = 350 WATTS CAUTION TO PREVENT SHOCK, DO NOT OPEN. SERIAL NUMBER ~ AC INPUT 115V/230V 50/60Hz FUSE 8A/250V, 300W (115V) 4A/250V, 740W (230V) 8 RETURN BALANCE 0 8 SEND RETURN 2 3 6 7 10 1. Fuse sled - This contains a fuse holder and shows the currently selected voltage rating for your Model 3500. Make sure the voltage rating is correctly set before powering up the amplifier!For information on how to change the voltage rating, see Appendix C on page 18. AC input - Connect the supplied standard 3-pin "EEC" plug here. Remove all packing materials (save them in case of need for future service) and decide where the amplifier is to be physically placed. To avoid potential overheating problems, be sure that the rear panel is unobstructed and that there is good ventilation around the entire unit, particularly behind the rear-panel fan. Begin by hooking up your bass cabinet or cabinets, using the 1/4" unbalanced Speaker output connectors on the rear panel; it is never a good idea to power up any amplifier that is not connected to loudspeakers. Hartke amps are optimized for use with Hartke bass cabinets, although other brands of speakers can be substituted. Any appropriately rated bass cabinet with a minimum impedance of 4 ohms (that is, 4 ohms or greater) can be used. In order to ensure correct phase correlation, the tip of the Model GX-365/3500 speaker jack should be connected to the "+" (hot) input of your loudspeaker, and the sleeve of the Model GX-365/3500 speaker jack should be connected to the "-" (ground) input of your loudspeaker. Driven to full power, they can damage connected loudspeakers, regardless of brand, size, or configuration. Care should be taken not to strain connected loudspeakers as this can cause permanent damage and will degrade the performance of the entire system. If you see connected loudspeakers moving excessively, turn your system down immediately or use the equalization and/or compression controls to reduce the amount of subharmonic (extremely low frequency) signal. Don't turn the amplifier on just yet, though. INPUT PASSIVE SPEAKER OUTPUTS 8 8 ACTIVE 4. Use a standard music instrument cable to connect your bass to the appropriate Input jack on the front panel (if your bass has active circuitry, * connect it to the "Active" input; if not, connect it to the "Passive" input). [. . . ] For example, as you play your bass, you'll probably find that some notes (for example, notes played on the upper frets of the lowest string) are considerably louder than others. The function of the Compression circuitry in the Model GX-365/3500 Bass Amplifier is to reduce overall dynamic range by automatically reducing the level of the loudest sounds you play so that they are closer in level to softer ones--the end result is that the sound "evens out" and all notes played have pretty much the same level. The front-panel Compression control determines the amount of compression (peak signal reduction) by simultaneously adjusting both threshold and compression ratio (which ranges from 2:1 to infinity [limiting]). At the fully counterclockwise "Off" position, the circuitry is bypassed and no compression is applied (the knob clicks when set to the "Off" position). [. . . ]