User manual ROCKTRON V250

[. . . ] It is also recommended that a vacant space is left above the power amp, if possible, to further improve ventilation. OPERATING TEMPERATURE Do not expose this unit to excessively warm or cold temperatures. This unit is designed to operate between 32°F and 104°F (0°C and 40°C). This unit may not function properly under extreme conditions. The lightning flash with arrowhead symbol, appearing on the rear panel of the unit, is intended to alert the user of this product of the presence of uninsulated, dangerous voltage which may be of sufficient magnitude to constitute a risk of electric shock. CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN The exclamation point symbol, which appears on the rear panel of the unit, is intended to alert the user of this product to the presence of important operating and maintenance instructions in the accompanying literature. CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK) NO USER-SERVICABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL Copyright ©1996 Rocktron Corporation. All rights reserved. Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] This will guard against any thumps or pops that could otherwise occur, potentially damaging speakers when power is cut to the amplifier. · Differential input buffers to eliminate ground loop hum coming from the power amp. · Over-temperature protection · Rock-solid design to provide reliable, trouble-free use. 1 Velocity 250 Design ® Designers have been working at creating solid state amplifiers which sound like tube amplifiers ever since the transistor hit the scene. We at Rocktron first produced the Velocity 150 & 300 amplifiers with that goal in mind. The Velocity 250 takes what those first models provided to a whole new level. Every tube amplifier has some amount of output impedance due to the output stepdown transformer. Conversely, solid state amplifiers have little or no output impedance, because the speaker terminals are connected directly to the output devices. This difference in impedance is the primary reason why the two types of amplifiers sound differently. The reason the output impedance makes such a difference is because these amplifiers get connected to speakers (which also have their own impedance curves), not 4 or 8 ohm resistors. When a tube amplifier drives a speaker--each with its own characteristic impedance--they react to each other (i. e. The engineers at Rocktron have developed a circuit which actually measures a speaker's impedance and changes the output response of an amp to match what you would hear from a tube amplifier--automatically!After developing this circuit, the only question that remained was "Which tube amp do we design to match to, since each one is different?". By giving you a variable REACTANCE control, you control the amount of effective* output impedance of the Velocity 250 to match any number of tube amplifiers. With the REACTANCE control at the minimum setting, a very low output impedance is simulated--similar to a good solid state amplifier. As the control is turned clockwise, the effective impedance increases and sounds more like a tube amplifier's output stage. *Note: The word "effective" is used because if we actually increased the output impedance to, say 2 ohms for example, and had a 2 ohm speaker cabinet (for a total of 4 ohms), we would lose one half of the power before it even got to the speaker!That means our 125 watts/channel would only be good for 62 watts/channel. But with the Velocity 250, you still get the full rated output delivered to the speaker. What this means for you is that you get an amplifier that will react differently with each speaker cabinet you use with it, just like a tube amp would do. Plus, you get to control how much reactance you want to tailor fit the sound to your needs. The REACTANCE control in conjunction with the DEFINITION control gives you an incredible amount of flexibility that few amps on the market can touch. And, if you are really power hungry and want to mono bridge your amp, you won't sacrifice any of these features. [. . . ] Should this condition occur, switch the unit off for approximately 10 seconds and make sure that the cords from the amplifier outputs are properly connected. When the power is turned on again with the proper connections, the amplifier will operate normally. It is important to note that two outputs from the amplifier should never be connected to the same speaker, as this would be equivalent to shorting the outputs together and will cause the unit to shut down. In the unlikely event that the proper connections have been made and the unit still shuts down, we strongly recommend that you first contact our Customer Support Department at the phone or fax number shown on the back cover of this manual before taking the unit to a dealer or repair shop for servicing. Definition Control When playing with other musicians, it often becomes a problem that the guitar can get "buried" under the other instruments and cannot be distinguished easily. [. . . ]