The Oberheim DPX-1 was released in 1986 and measures 19"X3.5"X14" (2 rack spaces high) weighing in at 18 lbs. The DPX-1 is a sample player with the ability to read samples of the following formats: Emu Systems Emulator II, Sequential Prophet 2000/2, Ensoniq Mirage and Akai S900. The S900 samples may only be read with units that have ROM version 2.0 or later. The unit is strictly a sample player with no ability to sample or modify the presets which are loaded into the unit.

The Voice

The DPX is an eight voice polyphonic instrument which converts all sample data to 12 bit linear data format. The DPX-1 uses a Motorola 68000 processor to perform this function among other things. The voice is routed trough a VCF and VCA and maybe modulated by an LFO. The samples are loaded via a 3.5 double density or 5 ¼ disk drive. All VCF, VCA and LFO parameters are read from disk and are not editable by the user with the exception of Filter Cutoff. With ROM 2.0 or later the filter cutoff may be adjusted from 0-99, while earlier versions allow the user to select filter wide open or the filter setting per the disk.

Front and Real Panel

The front panel is relatively simple offering five buttons, a 2 digit LED, two indicator lights, 2 disk drives and a volume slider. The 5 ¼ drive is read only and is used to read the Emulator II samples while the 3.5 drive offers read / write features with ROM version 1.5 or above (versions 1.4 and below offer read only). It is used to load all other sample formats other than the EII and to create backup files. A load disk button is used to instruct the DPX to load a sample bank. The DPX defaults to the 3.5 drive and if no disk is found it will than access the 5 ¼ drive. A function selector button scrolls through the various functions and increment and decrement keys scrolls through specific commands at each function level as well as operate as +1, -1 to numerical data. A 2 digital LED displays the current function or the value of the current function selected.

The power switch is unfortunately located on the rear of the unit making it impossible to turn the unit on and off if it rack mounted unless you have easy access to behind the rack. The rear panel also includes power cord receptacle (no wall wart), a ¼ inch mono audio out and midi in, out and thru. A 9 pin CD-ROM interface was available as an option which allowed the DPX-1 to interface with the Optical Media CDS3 CD-ROM drive. An eight individual voice output (¼ inch jacks) option was also offered. Finally a SCSI interface was offered to allow the DPX to read and write to a 20 meg hard drive known as the Oberheim HDX-20 (original price app. $1,799). The HDX-20 could read a bank in 4-6 seconds compared to the 20-30 seconds the floppy takes.

MIDI / Disk Functions

The DPX has a solid midi implementation. The unit will receive data in omni mode or poly mode channel 1-16. Recognized data includes midi notes, velocity, patch change and continuos controllers for pitch bend, vibrato, volume, sustain and pressure. The DPX will send patch change commands that are entered on its front panel via the midi out jack. The unit has the ability to send and receive samples via MIDI sample dump standard. ROM Version 1.5 also offers midi echo which combines midi information generated by the DPX-1 internally with midi data received at its in port and then sends all of the data to MIDI OUT.

ROM Version 1.5 or later allows for the creation of aback up file. The back up file is the contents of the DPX-1 RAM stored on a 3.5 disk. A back up file may not be created on a 5 ¼ disk. The 3.5 back up file may only be read on a DPX-1, not the original sampler that the bank may have come from. Since the back up file already has the sample data converted to the DPX-1 12 bit format, loading time will usually be shorter when loading a back up disk compared to the original. Unfortunately prior to saving a back up file, the disk must be formatted which takes approximately 2 minutes to perform. Saving the back up takes another 1 minute.

Conclusion

The DPX-1 is a great idea with one serious flaw which is the inability to edit presets. Its a shame that the Sound Designer I special versions (i.e. Emulator II or Prophet 2000) was never created to work with the DPX-1. The DPX’s usefulness is seriously limited unless you already have sample banks that are set up exactly as you wish to use them. However the DPX-1 is a excellent way to add 8 voices of EII, Mirage, P2000 and S900. It is cheaper that buying one of these samplers and you get the ability to read all four formats. I can only do a side by side comparison of the EII to the DPX with respect to how it sounds. The EII seems a little smoother sounding to me especially its filter. However the sound difference is very minimal but there is going to be a difference with the EII and the DPX since the DPX plays backs samples using linear 12 bit versus non-linear 8 bit on the Emulator II. I also think the filter is more aggressive sounding in the DPX-1 than the EII. So my preference is the EII over the DPX when it comes to the sound but the difference is very slight. The real advantages of the DPX is its price, its size (there was no Emulator II rack), the ability to get EII preset banks on 3.5 disk and most importantly the ability to read 4 different sample formats.

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