NOTE: If you are installing your new preamp in a rack system, it is important that it not be placed too close to a power amplifier. The transformer in the power amp radiates a field that could induce humm into the preamp. If you are experiencing a residual humm in your system, this may be the problem. It is easily solved by re-postioning the power amp or preamp,

Should you need to remove the rubber feet on the bottom of the Universal Stereo Instrument Preamp (USIP), be sure to replace the screws as they help secure the bottom panel to the chassis.

FRONT PANEL FEATURES

INPUT JACKS

CHANNEL 1: With its 10 Meg ohm input impedance, this 1/4" unbalanced input is ideal for piezo pickups and all devices needing a high input impedance. If you are not blending two signals, or do not need the stereo capabiliites, we recommend using this input regardless of the type of pickup or source.

Maximum input level for both Channels 1 and 2 is 1.5 Volts RMS. If you are experiencing distortion, and the O/L LEDís are not lighting, try turning down the level of the instrument.

STEREO: This feature will accept a dual signal, such as a pickup and soundhole mic, or stereo signal from a keyboard, etc. The TIP of the stereo jack is sent to Channel 1 (top row of controls). The RING is routed to Channel 2 (bottom row of controls).

When the Stereo input is used, it disables Channels 1, 2, and the XLR balanced input. Therefore, they cannot be used in conjunction with the stereo function.

BALANCED TRS: This is a truly balanced input for Channel 2. It has an impedance of 10K ohms. If needed, 12 volt phantom power can be applied to pins 2 and 3 using the Phantom Power switch. Microphones needing a minimum of 48 volts phantom power will not work with this input.

Wiring is as follows: Pin 1 = ground, Pin 2 = plus, Pin 3 = negative. This is American standard.

CHANNEL 2: This 1/4" unbalanced input has an impedance of 4 meg ohms. It is best suited for magnetic pickups, microphones, keyboards, drum machines and some piezo pickups. When used, it bypasses the balanced TRS jack, so they cannot be used simultaneously.

Twelve volt phantom power can be applied with the Phantom Power switch to the right of this jack.

PHANTOM POWER SWITCH: Pushing this switch to the In position applies 12 volts DC to either Pins 2 and 3 of the XLR input, to the RING of the Stereo jack, or to the Chan. 2 unbalanced input jack. This is indicated by the Amber LED lighting.

Note: Some mics, such as the Joe Mills, require a slight modification in the phantom power circuit to operate at peak performance.

Use this feature ONLY when you are using a soundhole mic or other device needing phantom power. Do not turn on the phantom power if nothing is plugged into the appropriate input.

O/L LEDS: An overload or "clipping" indicator is provided for each channel. Should your reach or near clipping, the red LED will light. To provide a ìwarningî, the LED activates 2dB BEFORE clipping occurs. To correct this condition, try turning down the GAIN control on the channel that is overloading.

As well, boosting a band in the Equalization section can cause the LED to light. For this reason, we recommend setting the EQ section with the Gain and Mater Volume controls set low. After completion, raise the Gain knob until the O/L Led barely lights when striking a loud note, then back it off slightly. Use the Master Volume to set your overall volume. This will help avoid accidental clipping, and provide maximum signal to noise ratio overall.

GAIN CONTROLS: Each channel is supplied with an individual Gain control. It affects the level going to the EQ section, and ALL Line Out, XLR and Send jacks. Once you have set your Gain to a desired level, use the Master Volume for ìliveî adjustments.

Remember that changing the level of the Gain control during a live performance will also change the level at the XLR. This can upset the person responsible for the "house" sound. Likewise, should the house need a hotter or lower level at the XLR, it can be adjusted with the Gain control. More info on the Gain can be found in the O/L section above.

PHASE SWITCH: A Phase switch is provided for each channel to help eliminate feedback and other phasing problems. In the Normal position, the inputs and outputs are in phase with each other. In the Reverse position, they are out of phase.

If you are experiencing early feedback with an acoustic instrument, try using the Phase switch to alleviate the situation. As well, remember that your position on stage can influence when feedback can occur. Always start out with the Phase in the Normal setting.

EQUALIZATION: The EQ section on the Universal Stereo Instrument Preamp was designed to enhance the ìessenceî of your sound, while maintaining the basic characteristics. It should be ideal for correcting room acoustics, equalizing ìhotî or "dead" spots on an instrument, or bringing out that certain nuance.

Boost or cut is achieved by adding or subtracting the original signal to itself. The bandwidths in the boost mode were chosen for "musicality", and are a function of frequency. The bandwidths in the cut mode are narrower, creating more of a notch filter affect. This allows the user to better pinpoint a problem area without drastically altering the true sound. You should notice the difference the first time you use it!

Each band labelled Bass, Mid, and High has two functions: the Level control; and the Frequency control. The LEVEL control on the left adjusts the desired amount of cut or boost just like a normal tone control. The FREQUENCY knob on the right sets the area of sound (frequency) to be adjusted. No sound alteration will occur with the Level set at the ì0î or flat (center click) position.

To get used to how the Level and Frequency functions work. try playing a chord on an instrument or listening to pre-recorded music. As you do, boost or cut one of the Level controls to near maximum. Then rotate or "sweep" the Frequency function next to it. Each band will give you a different range of coloration. The more you get used to each band and its properties, the easier you will find the area you wish to address. Popular settings are with the Frequency control set at mid or 12 oíclock position (80, 650, and 4.5K).

The Level control can boost (clockwise from 0) or cut (counter clockwise from 0) up to 15 dB. In some cases, if all tolerances are exact, a greater cut than -15dB can occur.

The numbered frequencies surrounding the Frequency control should be used as a guideline. To find the exact frequency you are searching for, start at the approximate position, then rotate the knob left or right to find that "sweet" spot.

NOTE: Boosting one or more EQ bands to maximum can cause the unit to clip, or run out of headroom. This will be indicated by the O/L indicator. To correct this condition, lower the Level or Gain control.

EFFECTS BLEND CONTROLS: There is a separate side chain effects loop and Effects blend control for each channel, as well as the mono blended signal of channels 1 & 2. The amount of effect heard in the sound is adjusted by the appropriate Effects blend function. As you turn the control clockwise, or towards the "Wet" position, more effect will be heard. If your effects device has a blend control, turn it all the way up.

If you do not hear a signal coming from your effects, or any other device you have plugged into the Effects Return jack, check the position of the correct Effects control. Please see "Effects Loops" for more information.

BALANCE CONTROL: The Balance adjusts the mix of Channels 1 & 2 at all outputs including the Headphones. If you do not hear sound coming from one of the channels, check the position of the Balance control.

Turning the Balance control towards "1" decreases the level of Channel 2. Likewise, turning the control towards "2" decreases the level of Channel 1.

NOTE: Remember that the Balance control will affect the levels at the Line, XLR, and Headphone outputs.

MASTER VOLUME: The Master Volume adjusts the level at the Line Out of Channels 1, 2, and the mono Blended Line Out. It DOES NOT affect the level at the Balanced XLR outs. In this way, you can adjust the level going to an onstage monitor or amplifier without changing the level going to the house mix or recording console.

HEADPHONES: With the headphones, you can monitor your sound before sending it to the house, or practice along with pre-recorded music or a drum machine, etc.

Included in the headphone mix will be any device you have inserted into the STEREO MIX IN jack, or effects you have in Channels 1 or 2. The Mono blended effects loop is NOT included.

Since the MUTE does NOT affect the headphones, you can tune up or "audition" your sound without sending it to the XLR outputs (in the Mute mode).

STEREO/MONO SWITCH: This sets the mode of the headphones. If you have a dual source or stereo instrument inserted into the inputs, you can hear them individually in the STEREO or OUT position. If you are using just one channel and wish to be heard in both sides, push the switch to the MONO or IN position. Keep in mind that the Balance control affects the levels in the headphone mix.

VOLUME: This adjusts the level in both channels of the headphone mix.
NOTE: It is important to be aware of the position of the headphone Volume control. Should it be turned way up causing the headphone circuitry to clip, it could introduce distortion into the main signal. For this reason, if you are not using the headphones, keep this control at minimum or full counter-clockwise.

HEADPHONE JACK: Use a high quality pair of headphones having an impedance of at least 32 ohms or greater. The best match for the USIP is 75 ohms. You can order matching headphones from Raven Labs direct for $28.00 each. These are made by Yamaha to our specifications.

MUTE: You can activate the Mute function with either a footswitch or the push button switch on the front panel. The USIP is in the Mute mode when the red LED is lit.

Use the Mute function during brief periods such as changing instruments or tone settings, etc. If you are going on a break for an extended period, it is best to turn the unit off.

FOOTSWITCH JACK: Any single footswitch having a mono 1/4" phone plug can be used in the Footswitch jack. A stereo 1/4" phone plug will not work unless the tip and ring are shorted.
NOTE: Inserting a footswitch BYPASSES the Push switch next to it.

POWER SWITCH: Pushing the Power switch in turns on your preamp as indicated by the blue LED lighting.

NOTE: Since there are turn on and turn off transients, the USIP should be turned on first, and turned off last. Plugging or unplugging cables to the outputs when the unit is on will not cause any harm. All outputs are short circuit protected.

Be sure your A/C adapter is inserted fully into the adapter IN jack. Plug the adapter into the USIP FIRST, then into the wall socket. DO NOT leave the adapter plugged into the wall socket after your performance.


REAR PANEL FEATURES

EFFECTS LOOPS: There is a side chain Effects Loop for each individual channel, and the Mono blended signal. Each loop has a SEND and RETURN jack. To use these, plug a shielded cable from the SEND jack to the INPUT of your effects. Then plug a second shielded patch cord from the OUTPUT of your effects to the RETURN jack. Use the Effects Blend Control on the front panel to adjust the amount of effects with the sound of your instrument. If the Effects control is in the full Dry (counter-clockwise) position, your effects device will NOT be heard. To introduce more of your effect into the overall sound, turn the Effects control towards the Wet (clockwise) position.

You may also use the Return jack to mix in other exteranl signal such as a mono tape source, drum machine, etc. As well, the Send jack on Channels 1 or 2 can be used as a "Pre Master Volume" line out. The Mono effects loop is post Master Volume.

To use a Stereo Effects unit, run a patch cords from the Sends of Channels 1 & 2 to the left and right inputs of the stereo effect, then a second set of cables from the left and right outs to the Return jacks of Channels 1 & 2.

Output impedance of the Send jacks is 100 ohms. Impedance of the Return jacks is 27K minimum.

STEREO MIX IN: If you wish to mix in a stereo signal from a CD or cassette player, use the Stereo Mix in jack. This can be especially useful for practicing along with pre-recorded music, or playing live with additional background music.

The level in the "mix" from this jack depends on the level coming from the device. Therefore, use the volume on the CD player, etc. for desired levels.

The TIP of the Stereo Mix In jack goes to Channel 1. The RING goes to Channel 2. Their input impedance is 27K ohms.

TUNER SEND: To tune up silently between songs without disturbing your band mates or the sound engineer, hook up a tuner to this jack and activate the Mute switch. Since the Tuner Send is on a side chain, it will not load down your instrument.

NOTE: The signal present at the Tuner Send jack is received from Channel 1 only.

BALANCED XLR OUTPUTS: Each channel has itís own post EQ Balanced DI. The XLRs are electronically balanced and can be used to send a signal to a tape deck or mixer for recording and live situations.

Wiring of the XLR is American Standard: 1 = ground; 2 = hot; 3 = neutral.

The level at the XLR is affected by the Gain control only. The Master Volume does NOT affect the Balanced Outs. To ìkillî the signal at the XLR, simply use the Mute switch on the front panel.

The GROUND LIFT SWITCH either grounds pin 1 of ALL XLR outs, or removes (lifts) ground. This can be useful for eliminating ground loops or humm problems.

The Balanced Outs are grounded with the push switch in the normal or out position. To LIFT the grounds, push the switch IN.

ALWAYS START YOUR PERFORMANCE WITH THE SWITCH IN THE GROUND (OUT) POSITION.

LINE OUTS: Present at Line Out 1or 2 is the individual signal from Channels 1 or 2. The Mono Line Out will have any signal present from channels 1 and/or 2. The level at these jacks is adjusted by both the Gain, Balance, and Master Volume controls. These outputs can be used to send an unbalanced signal to an amplifier or any piece of equipment desired.

Always use good quality shielded cables when using any of the input or output jacks on your Universal Stereo Instrument Preamp.

A/C ADAPTER IN/OUT JACKS: Insert the A/C adapter that came with your unit into the IN jack of your preamp first, then plug the adapter into the wall socket or power strip second. This will avoid accidentally shorting out part of the mini stereo plug to ground when first inserted. You can use the OUT jack to power (daisy chain) other equipment from Raven Labs. To do this, use a mini stereo to stereo patch cord. Since the adapters output is + and - 12 volts DC, the cable will not induce humm into other equipment.

NOTE: ALWAYS remove the adapter from the wall when not in use.