User manual MILLENNIA TD-1

[. . . ] 1 Twin Direct Recording Channel TD-1 Instruction Manual Rev A3, 6/03 (2500) © 2003, Millennia Media, Inc. Litho in U. S. A. Twin Direct 2 ONE YEAR WARRANTY Millennia Media will repair this product, free of charge, in the USA, in the event of defect of materials or workmanship for one (1) year following date of purchase. This warranty is extended only to the original purchaser. This limited warranty covers failures due only to defects in materials and workmanship that occur during normal, intended use and does not cover damage which occurs in shipment or failures which are caused by products not supplied by Millennia. [. . . ] This could damage both microphone and the sensitive HV-3 front end. INPUT GROUND LIFT / ISOLATE Pushbutton Switch A switch which removes the ¼" Instrument (DI) Input ground from TWIN DIRECT's internal audio grounding. This switch also employs an internal jumper which selects true ground lift, or ground "isolation" via resistive and capacitive coupling (See Jumper Map). When jumper is installed and this switch is depressed, ground is isolated via series resistance. When jumper is not installed (factory default), and switch is depressed, ground is lifted. A momentary pop may occur when lifting grounds ­ you may wish to remove power from the TWIN DIRECT when experimenting with any ground lifting technique. Note that Input Ground Lift / Isolate should only be used in cases where a ground loop cannot be corrected by first lifting earth or output grounds. Lifting earth ground from power ground will usually correct ground loops and hum problems. Of course, for safety, never defeat the earth/chassis power cord ground bond. Always assure that the "third pin" (earth ground) on the IEC power cord remains connected to the TWIN DIRECT's IEC input connector. If you must lift earth ground, you may do this via the rear panel switch. (See "Earth Ground / Isolate Lift" switch and "Output Ground Lift" switch, below. ) POLARITY REVERSE Pushbutton Switch A switch which reverses polarity of the TD-1 signal path immediately after the gain adjustment amplifier. Polarity on main outputs is flipped 180 degrees with respect to the input when this switch is depressed and illuminated. SPEAKER SOAK tm INPUT Pushbutton Switch TD-1 17 A switch which allows the Instrument DI / Speaker Soak Input (above) to accept signal directly from the output of a power amplifier connected to a speaker cabinet. Note that the power amplifier must be plugged into speakers designed for the full power rating of the amplifier whenever the power amplifier is feeding the TWIN DIRECT. A typical application would be taking a parallel feed from a guitar amplifier or speaker cabinet during live or studio performance. Power amplifier output should be wired in "parallel" with speakers and the TWIN DIRECT's Instrument Input jack. TWIN DIRECT will not effect the sound or performance of the power amplifier or speakers. TWIN DIRECT will accept power amplifier input when this switch is depressed and illuminated. Insert a power amplifier into the TWIN DIRECT only when this switch is depressed and illuminated. Failure to do so could result in serious damage. Wonderfully rich and spacious electric guitar recordings can be achieved by using a pair of microphones on a guitar speaker cabinet, along with a direct feed into TD-1's Speaker Soak input -- with all three signals mixed together. Try using a pair of sonically dissimilar microphones, such as a Royer 121 and Josephson 606 (two of our favorites). Place each mic in a different position to maximize its unique strengths. [. . . ] Design inconsistencies among audio product manufacturers, along with the variables of real-world recording environments (such as AC power irregularities in large auditoriums and old churches) can present the recording engineer with "ground" far from zero volts potential, or even multiple "AC power grounds" exhibiting varying potential throughout a building or stage. Because of these wide variations, a well-designed DI box must effectively anticipate all manner of audio and electrical systems. To remedy most interface problems, TWIN DIRECT provides five different methods of ground alteration options, allowing an unusually high level of user control over hums and potential mismatch. A WORD ON ISOLATION Inside TWIN DIRECT are jumpers which allow Input and Earth Ground Lift switches to be converted to Ground Isolation paths. Ground Lift is a complete removal of all internal ground paths (earth, power, or audio) from the targeted audio connector(s). [. . . ]