Ultrasound Amplifiers DI Plus Pre-Amp Unit

Sale price$89.00
In stock

Pickup available at 199 4th Street Troy, NY

Usually ready in 24 hours


Used pedal in very good condition with normal signs of use. 

No battery nor any accessories included. 

Collar City Guitars is a Preferred Reverb Seller, buy with confidence!


The UltraSound Ultra PDI Preamp DI is a great direct box and a full-featured preamp. The Ultra PDI lets you dial in clear, natural sound. Routes to a stage PA from a balanced XLR output. A parallel 1/4" out sends signal to your stage amp. The effects loop features a 1/4" send and return rather than a TRS system requiring a Y cord. Tone controls include active bass and treble EQ, mid-dip shape control, and a notch filter. Operates on 48V phantom power or battery (not included).

UltraSound Ultra PDI Preamp DI Features:

  • Full-featured preamp and DI box
  • Bulletproof metal housing
  • Input gain control to allow proper setting for the great variety of acoustic pickup outputs
  • Balanced XLR output for routing signal to PA system
  • Parallel 1/4" out for sending signal to stage amp
  • Both stage and PA outputs have their own level controls
  • Parallel input jack allows a tuner to be plugged in in-ine without degradation of signal
  • Effects loop
  • 48V phantom power capability
  • Active bass and treble EQ
  • Mid-dip shape control permits removal of honky mids
  • Notch filter permits dialing out problem feedback
  • Combination of controls allows any acoustic player to dial in a natural, useable sound at amplified volumes

INSTRUMENT INPUT: This input is designed for all passive and active type pickup signals. When a plug is inserted, the 9V battery is switched on.

INSTRUMENT OUTPUT: This is a "parallel" jack which can be used to send the "guitar/instrument signal" to an external tuner, guitar amp or other device which can use an instrument level signal.

EFX LOOP: This is a real world "EFX LOOP". In an effort to save room, most of our competition uses a TRS jack (tip, ring, sleeve) and Y cable type system. The DI+ is provided with two 1/4" jacks, one for "SEND" and one for "RETURN". Since the EFX LOOP interrupts the signal path it can be used as an insert point for a volume pedal, compressor, or tuner, if the tuner is equipped with a bypass switch. (Try that with one of our competitors units)

SEND: The signal on the SEND jack is post-input gain and pre EQ. This means that you can use the SEND signal as an auxiliary unbalanced direct output. This signal is not affected by any of the panel controls with exception of the "INPUT GAIN" control.

RETURN: A plug inserted into the RETURN jack will interrupt the signal path. The signal on the tip of the plug inserted into the RETURN jack will be the signal that the DI Plus will process.

INPUT GAIN: The "INPUT GAIN" is not a volume control, rather this control sets the level of amplification applied to the input signal to boost it to a useable level. The reason this is adjustable is to accommodate a wide range of pickup devices.

BASS: This is an "Active" control. The BASS control adjusts the amount of cut or boost in the low frequency (150HZ) range.

TREBLE: This is an "Active" control. The TREBLE control adjusts the amount of cut or boost in the high frequency (5kHZ) range.

NOTCH FILTER: ON/OFF - Enables or disables the NOTCH FILTER control.

FREQ. HZ - Sets the frequency (100-350HZ) of the 18db cut NOTCH FILTER that is used to control resonant feedback.

SHAPE: ON/OFF - This toggle switch enables or disables the SHAPE control. This control is a mid dip control. In the ON position, the mid frequencies will be cut and the high and low frequencies will be boosted.

PHASE: IN/OUT - Changes the polarity of the signal. Phase affects the way the guitar top is pressurized by the loudspeakers. When the signals are out of phase with each other, low-end feedback is minimized. If you experience “positive acoustic” feedback on stage, flip the phase switch from its current setting to see if this will kill the feedback. If inverting phase alone does not eliminate feedback, the notch filter can be used. Phase will also affect the way the guitar signal mixes live and when recording.

XLR LEVEL: This control adjusts the amount of signal sent to the XLR OUT jack.

LINE LEVEL: This control adjusts the amount of signal sent to the LINE OUT jack.

48V : (Phantom Power) This LED lights when there is 48V Phantom Power present on the XLR OUT jack. No battery drain will occur when Phantom Power is present.

POWER: This LED indicates the DI PLUS is ready to operate. The POWER LED will illuminate when:
A. A plug is inserted into the INPUT jack and there is a fresh battery installed in the DI PLUS.
B. A 9VDC adapter (Wall Wart) is plugged into the power jack. (9VDC Regulated Power Supply - 500mA) (2.1MM DC Power Plug, Center +)
C. There is 48V phantom power on the XLR cable plugged into the XLR OUT jack. (The 48V LED and the POWER LED will both be illuminated.)

XLR OUT: Plug a standard XLR cable from your PA or recording console into this low impedance balanced output. Use the "XLR LEVEL" control to set the output level which matches up best with your PA or recording gear and gives you the least amount of noise. If your board provides 48V phantom power on the XLR cables, the DI Plus will run from this and save the battery. It is suggested that you keep a battery in the unit as a backup when using the phantom power. If the phantom power drops, the DI Plus will automatically switch to battery power.

LINE OUT: This is a standard unbalanced line level output signal. Use the "LINE LEVEL" control to adjust the signal level on this jack. This output can be used simultaneously with the XLR OUT jack for some creative signal routing. Plug a standard instrument cable from this output to a stage monitor amp or unbalanced Mic input on a mixer.

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