Test Drive: The Ensoniq DP/4 Parallel Effects Processor

by Jerry Vigil

Out of the box, the DP/4 Parallel Effects Processor has 400 factory presets. However, 88 of them "have been hidden to avoid confusion for the first-time user." That quote is taken right from the manual!


We've Test Driven a lot of effects boxes over the years, but this is the first one that goes so far as to conceal some of its power until the user is comfortable enough with the unit to access it. But don't let this scare you away from the DP/4. These "hidden" presets are tucked away to give the user time to comprehend the fact that the DP/4 is not like your typical effects box. You're given a chance to grasp the fact that the DP/4 is four mono-in/stereo-out effects units in one, and that these four units can be connected to each other in virtually any configuration you desire. You come to understand that you have the option of using one, two, three, or four different signals as input, and you take in the idea of using four outputs instead of one or two. Once these things are clear, the other 88 presets are less intimidating. But to understand these facets, some serious time with the manual and the machine is in order. Still, if you're the type that likes to plug in right away and begin accessing presets, the DP/4 is friendly enough to use right out of the box with little reference to the manual.

Before getting inside the DP/4, a brief tour around the box shows eight knobs on the left of the front panel. The bottom four are the output levels for each of the four output channels. The four knobs above these are the input level controls for each of the four input channels. Above these knobs are LEDs to indicate signal levels going into each channel as well as red peak LEDs which light when inputs near the overload level. The displays consist of one 2-digit LED display and at 32-character LCD display. To the right of the displays is the Data Entry Knob used for selecting presets and adjusting parameter values.

Other front panel controls include buttons labeled Write/Copy, Cancel/Undo, Select, Edit/Compare, System/MIDI, and Config. Two left/right arrow buttons are used for naming presets, scrolling through presets, and selecting parameters for adjustment. The four buttons labeled, A,B,C, and D access the four effects units in the DP/4. The back panel contains MIDI IN/THRU/OUT jacks, the AC power plug, a jack for a foot switch and another for a control voltage foot pedal, and finally, the four input jacks and four output jacks. (A second input jack for channel 1 is placed on the front panel for convenience.)

Now, here's where the fun begins. Sit down and pay attention.

There are forty-six effects algorithms in the DP/4. They are: Small Room Rev, Large Room Rev, Hall Reverb, Small Plate, Large Plate, Reverse Reverb, Reverse Reverb 2, Gated Reverb, Non Lin Reverb, Non Lin Reverb 2, Non Lin Reverb 3, MultiTap Delay, Dual Delay, Tempo Delay, EQ-DDL-with LFO, VCF-Distortion, Guitar Amps 1, 2, and 3; Speaker Cabinet, Tunable Speaker, Rotating Speaker, EQ-Chorus-DDL, EQ-Vibrato-DDL, EQ-Panner-DDL, EQ-Flanger-DDL, EQ-Tremolo-DDL, Phaser-DDL, 8-Voice Chorus, Flanger, Pitch Shifter, Pitch Shift-DDL, Fast Pitch Shift, EQ-Compressor, Expander, Keyed Ex-pander, Inverse Expander, De-Esser, Ducker/Gate, Rumble Filter, Parametric EQ, VandrPolFilter, and Sine/Noise Generator.

These algorithms account for 43 of the 46. (We'll get to the others in a moment.) Each of these algorithms occupies only one of the four effects units in the DP/4. They are referred to as "1 Unit" algorithms. Variations on these algorithms are stored in 100 of the 400 presets and are called "1 Unit Presets."

Comments (4)

This comment was minimized by the moderator on the site

Great article, even several decades later !
Well it's 2020, and I just bought a DP/4 for $200 USD.
I decided to sell my TC Fireworx ($500), and replace it with Ensoniq's DP/4.
Almost 30 yrs later, the DP/4 remains to be one of the best multi effects processors made ever.
This article was so insightful, I saved it as a PDF for future reference.
Thanks !

This comment was minimized by the moderator on the site

Thanks, Daniel. That's a good price for this box. I actually still have this very unit. It's right behind me, plugged in, turned on, and has my Strat plugged into it. I don't think I have any other gear that has lasted this long. Every aspect of it still works flawlessly. Enjoy it!

Jerry Vigil
This comment was minimized by the moderator on the site

I keep it around just for the organ patches.Send a mediocre mono organ track in, and you get a very convincing, wide, and moving organ with Leslie. I use the jazz guitar patch also. The others sound pretty dated, but can be modified easily enough.

Mine has recently developed an issue where after being on for 20 minutes or more produces a fairly loud mid-frequency noise, and the effect signal is no longer present.

Bud Martin
This comment was minimized by the moderator on the site

I always hear engineers talking about "replacing the caps" in old equipment to get them back to good working condition. If your unit has had a lot of on time, that might be all it needs. Sometimes you can see a bad cap. That's when it's an easy fix. Otherwise, it's a bigger task.

Jerry Vigil
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