Kurzweil 1000 Series 1000PX 1000HX 1000SX 1000GX Rompler modules

Last Update 03-12-2024

In fall 1987, Kurzweil introduced the 1000 series romplers as a cost effective derivative of their famed Kurzweil 250. These modules were strictly sample playback (aka "romplers") and did not have the sampling facilities of the big brother 250. When the 250 was released in 1984 amid rabid pre-release buzz, it was one of the first samplers to include a respectable piano sound coupled with an 88 key weighted action. You have to consider that a decent traditional piano sound in electronic portable format did not exist before the 250. The 250 also boasted an incredibly good sounding sample library comprised of traditional and contemporary sounds. It made history as the first sampler to generate very authentic sounding samples and you could produce an entire orchestra at your fingertips. That 250 piano sound was so good that it prompted a lot of customer requests to put that sound in a compact box, so Kurzweil designed the 1000 series as a response.

These 1000 series modules are best for "bread-n-butter" sounds like piano, organ, strings, percussion, and brass. However there is no onboard filter or effect processor. There are "compiled effects" such as chorus, echo, vibrato, tremolo, rotating speaker (Leslie), and phaser but these effects are created with layers that steal voices so they will reduce polyphony. Effects such as rotating speaker was not terribly authentic for the Hammond organ snob in me. I came to prefer the superior sonics and tweakability of outboard processors anyway, especially with four stereo output pairs between my four units. If you want to make synthetic sounds such as those made with analog synthesizers, these are not the best tools. If you want to realize orchestral arrangements, they don't come any better than these.

The 1000PX professional expander, 1000HX horn expander, 1000SX string expander, and 1000GX guitar expander were part of the first generation 1000 series that also included the 76 key K1000 keyboard system which was essentially a 1000PX in a portable keyboard format. They filled a market need for gigging keyboardists who couldn't afford the huge 250 and didn't need the sampler, sequencer, SCSI/external sync, and automated mixing facilities of the 250 (in 1984 the only other systems with those kind of tools were the $$$$$$ Synclavier and Fairlight).

In 1988, my MIDI system started with a new 1000PX driven by a MIDIBoard which is a powerful combination. With an early Microsoft DOS sequencer software (showing my age here!) I had a field day creating songs, and it didn't take long before my bold arrangements taxed the 24 voice polyphony of the lone 1000PX. During those days I was doing a lot of business travel around the states and I liked to check out the local music stores. I eventually learned of the other expanders and found used units while on business trips. Acquiring a 1000GX was a challenge as it was an uncommon unit - the only one I could find was new and I had to pay full retail for it. Today these units can easily be found for under $400.

These modules have served me very well in my MIDI system. I made a conscious decision to purchase like units for two reasons. One, they all use the same interface and OS so my learning curve was minimized in that once I learned one module, I could operate the others right away. Two, the quality of the sound was excellent. Kurzweil credits the sound quality to their proprietary 16 bit floating point "contoured sound modeling" system which maintains high signal-to-noise ratio and eliminates the "grittiness" of earlier samplers as the sample decays to silence. I later read that "contoured sound modeling" implemented a DAC coupled with a VCA on each voice. In cheaper systems, the DAC controlled both dynamic range and sample generation - however as the sample decayed, you could hear the "grittiness" or "stepping" as the DAC'd signal fell into the lowest bits of the digital resolution. In Kurzweil systems the VCA handles the dynamic range - the DAC always generates a "normalized" signal at or near full digital resolution while the VCA handled dynamic range control. Since the VCA was an analog component it improved the S/N ratio and eliminated the "grittiness" of inferior systems. This system was implemented on a custom very high scale integrated IC known as "Arnold".

The 1000 modules contained sample libraries known as "soundblocks" in Kurzweil lingo, stored on high density EPROMs - EPROM is a read only memory (ROM) that is electrically programmable (EP), hence ROM leading to the slang "ROMplers". These samples were high quality using sampling frequencies of 50Khz or 60Khz when everyone else was struggling to break through the 15Khz barrier. Kurzweil also went to great lengths to get quality samples by hiring professional musicians using professional instruments in professional studios. The post-processing optimization of samples across the keyboard range is so well done that I was hard pressed to hear transitions between ranges. Kurzweil opted for authenticity as the traditional instruments only play back within their true range IE the soprano sax will not extend all the way down to MIDI note #1.

Besides the excellent sample library, these units were fully multitimbral dynamically across all 16 MIDI channels - heady stuff for 1987! And with 24 or 20 note polyphony and the ability to chain multiple 1000 units together to expand polyphony, these were serious tools (IE using two 1000PX modules, unit (1) responded to 1st 24 notes, unit (2) to next 24 notes while giving you two sets of stereo outputs). And these 1000 series modules had such a robust OS that I never noticed any latency issues, especially when feeding them dense MIDI data streams.

Each unit came stock with a base "soundblock" sample library. Kurzweil offered expansion of the sample library via optional soundblocks in the form of 4MB 27C040 EPROM chips. You also needed the associated "setup" 27C256 EPROM which is unique to each module, so it is not always possible to mix soundblocks between modules. Also blank EPROMs of these densities are fast becoming obsolete. The other barrier to mixing soundblocks is the different sample frequencies. IE you can't put the 50Khz PXA/PXB sets in a 60Khz HX/SX/GX, but later derivative modules did combine soundblocks from HX and SX libraries. There is no facility to import custom user samples. This table outlines the sample library of each module and its associated optional soundblocks:

Model	Polyphony # of voices	Sample frequency	Soundblock samples
K1000	24	50Khz	Base: Grand pianos, electric organs, string sections, trumpets, baritone horn, clarinet, choirs, vibes, acoustic bass, digital waveforms.
			*PXA: Rhodes pianos, flutes, drums, percussion
			*PXB: Tenor sax, steel string acoustic guitar, distorted electric guitar, extended percussion, extended flutes, extended horns, marimba, harp
1000PX	24	50Khz	Base: Grand pianos, electric organs, string sections, trumpets, baritone horn, clarinet, choirs, vibes, acoustic bass, digital waveforms.
			PXA: Rhodes pianos, flutes, drums, percussion
			PXB: Tenor sax, steel string acoustic guitar, distorted electric guitar, extended percussion, extended flutes, extended horns, marimba, harp
1000HX	20	60Khz	Base: Trumpet, muted trumpet, trombone, tenor sax, digital waveforms.
			HXA: Alto sax, baritone sax, soprano sax, growl sax, brass stabs, extended digital waveforms
1000SX	20	60Khz	Base: String sections, violins, cellos, pizzacoto strings, digital waveforms
			SXA: Flutes, french horns, bassoons, clarinets, oboes, tympani, extended digital waveforms
1000GX	20	60Khz	Base: Steel string acoustic, nylon string acoustic, hollow body jazz, clean electric, lead electric, mutes, harmonics, electric bass, acoustic bass, digital waveforms. No expansion soundblock was ever offered for the 1000GX.

*K1000 requires a long-out-of-production daughterboard to accommodate PXA/PXB expansion. Derivative K1000 products such as the K1000SE did not require the daughterboard for expansion.

Many of the samples have mellow/bright variations. Sharp eyes will notice some redundancy of samples across the models. The sound differences - due to different sampling frequencies - are subtle but I can hear them. String sections are really close but the brass and guitars are better in the higher resolution samples.

I have many favorites in this sample library as well as some I no longer use. The electric organ was supplanted by my Hammond XK3 with Dynacord CLS-222 Leslie Simulator because it is far more authentic and the 1000 organ samples do not include drawbar control. Drums and percussion were abandoned because today's drum ROMplers are far more variable and authentic, and I prefer separate audio outputs for outboard processing (each 1000 module has only a stereo output). But back when I was starting out they did the job. The piano still stands up today, an impressive feat since 1987. The Rhodes samples are tolerable but I eventually reverted to the real thing as I have yet to hear a sample that captures the dynamic timbre (and crossfading isn't the same effect), and there was always some range of notes in a sample set that were weak. I still find many uses for the orchestral samples and the offerings of newer romplers are not significant enough to justify upgrading. And the samples in the highly underrated 1000GX have yet to appear in any Kurzweil product since the era of the 1000 series - not even the newer Young-Chang K2x00. I really love playing the GX nylon and steel string acoustics from a keyboard, and since I also play guitar I can simulate a lot of guitar techniques on a MIDI keyboard. Playing fingerpicked patterns is especially effective. I'm also a competent bass player and the GX electric basses are really cool (check out the "Jets" song below).

The optional soundblocks have not been available since 1000 module production ceased in 1992. The last OS version was v5.0 which implemented MIDI program banks along with many additions. The 1000GX never had OS newer than v1.93 from the factory, but Sweetwater Sound did offer a v5.0 OS upgrade for the 1000GX so I grabbed one for the sake of convention across all my modules (OS EPROMS are not interchangeable between different modules). Sweetwater was the best support center for the 250 and 1000 products so Kurzweil granted them some exclusive liberties. Today the only way to upgrade the OS is to copy the EPROM from another unit, which requires an EPROM burner and some blank 27C512 EPROMs which are fast becoming obsolete.

If the module locks up, you can perform a soft reset without destroying user programs or parameters - press the NO, YES, and PLAY/EDIT buttons simultaneously. If this does not work, cycle the power. If the unit still locks up after a power cycle, you have to perform a hard reset by holding down the NO and YES buttons while turning the power on. A hard reset will delete all user programs and configurations so this should only be done as a last resort.

The OS has a handy MIDI monitor that can be activated by pressing PLAY/EDIT, CHANNEL UP, and CHANNEL DOWN buttons simultaneously. The LCD display will display incoming MIDI messages but no sound will be generated from the 1000. Pressing any key exits the MIDI monitor and reverts to normal operation.

There are later derivative products such as the K1000SE, 1000PX Plus, 1000AX, Ensemble Expander, Ensemble Grande Piano, and Pro I/II/III. They all used the same soundblock family and the different models had a combination IE the 1000AX had both SX and HX soundblocks but I do not know if they offered the SXA/HXA options for the 1000AX (remember they need the associated "setup" EPROMs). Kurzweil even had another line of "home" keyboards that used the 1000 technology to obfuscate the model history even more! The last generation was known as the 1200 series. The 1x00 family is pretty extensive and convoluted so keeping track of which products used which soundblocks requires a scorepad (I did compile a table of the features of the non-home models here). If you're after all the bells and whistles, look for the 1200 keyboards or Pro modules.

One of my beefs with modern digital pianos is that their action is too stiff, I literally cannot play some piano techniques on them. I wanted a single unit digital piano for simple gigs where I didn't need to haul the MIDIBoard and a rack of 1000 units. I owned some of the new digital pianos and sold them. I would try new models at stores and at NAMM shows, and they all were so bad that I gave up on new models - even the new Kurzweils were too stiff! So I pounced on a used Kurzweil 1200 Professional which has 88 weighted keys. This choice was also driven on the convenience that this model is part of the 1x00 family so I could load my Kurzweil 1000PX user library in it. While the K1200 Pro isn't the same weighted keyset of my MIDIBoard, the keyset is much better than the stiff ones found on modern digital pianos. And I was already familiar with the interface and my own sound library - problem solved.

I dug through my recording library and uncovered four songs that demonstrate the 1000 modules. They were played back from a MIDI sequencer straight to two track. The only processing is a cheap ART Multiverb (hey we had to start SOMEWHERE). They are 100% Kurzweil with the exception of Moog Source bass and Memorymoog pads/sweeps on "Teach Me Lord" and "Jets".

Sleigh Ride orchestral arrangement

Frosty The Jazzman big band

Teach Me Lord contemporary

Jets funk/fusion

The feature set of the 1000 modules are impressive (for 1987) and the MIDI implementation is very comprehensive and complete - the 1000 modules is one of the precious few that will respond to release velocity (handy for dynamic control of release tails) and polyphonic aftertouch (incredible for volume swells of individual notes). The choirs in "Teach Me Lord" exploit polyphonic aftertouch. The Kurzweil MIDIBoard is one of the few MIDI controllers that can generate release velocity and polyphonic aftertouch - but use polyphonic aftertouch sparingly as it will generate a pretty dense MIDI data stream that can choke the bandwidth! I acquired a lot of service documentation from Kurzweil during those days - among them are software details for third party developers and the firmware was written in C++ object oriented language. The Kurzweil software team was highly advanced!

The owner's manual is well written and the hierarchy of the system is pretty logical. Despite the sparse panel of buttons and a 40x2 LCD, navigating the system isn't too hard. Thankfully, many of the parameters have real world units such as cents or dB or seconds - way too many music devices use abstract numbers which is zero help in predicting the result of tweaking. The 1000 series have a generous RAM capacity for custom patches and I never reached the limit on any of my units. After the first ten years of owning them I pretty much defined and cataloged the sounds I would use and have rarely edited them since. Obviously as my studio expanded to include other keyboards, some of my patches in the 1000 modules became obsolete. These modules can be remotely edited over MIDI but I don't really use remote editors so I don't know of any current software that can edit 1000 modules. I had a couple of DOS editors but never really used them.

The configuration heirarchy is divided into Master, Program, and Layer levels. Master parameters affect the entire module and include parameters such as tuning, MIDI configuration, transpose, velocity maps, program maps, audio mono/stereo, sysex dumps, and intonation tables with reference key (equal tempered, just, harmonic, indian, arabic, and user-defined 12 tone scales). Program level affects all layers in a user patch with facilities for naming, saving, deleting programs, channel stealing, polyphonic limit, and a solo/mute option for editing layers.

User patches can have up to four layers. Remember if you use a "compiled effect", this will consume layers. The layers are where the patch parameters are defined and many of them will be familiar to experienced sound designers. If you are viewing a layer that is part of a "compiled effect" then only a limited set of parameters are accessable. Once you configure the effect to taste, you can convert it to modular for full editing. Modular makes all of the layer parameters available. You can duplicate layers or import a layer from another patch. Once you define the sample sound for a layer then you can define volume, panning, key range, keyboard tilt (louder or softer depending on key number), transpose, detune, delay, dynamic range, controller pedals, compiled effect, balance (crossfade), alternate attack with trigger source, and layer trigger (from a MIDI controller or modulation source). Lots of control options here.

As for modulation source options there are two global LFOs, two local LFOs, two global loopable ASRs, two local loopable ASRs, mixers, inverters/negators, amplitude multistage loopable EGs (if you don't use this there is a default EG associated with each sample), generic multistage loopable EG, envelope control (for scaling transient times with a MIDI controller or modulation source), pitch control, and amplitude control. Many of the modulation settings can be triggered/modulated by a MIDI controller as well as any other modulation source. The LFO waveforms are quite extensive with sine, cosine, sawtooth, square, triangle, double pulse, staircase, all with phase shift or bipolar or +/- unipolar or asymmetrical options as well as white, pink, red, and blue noise. Whew!!!

This is a powerful unit as it is, although it's a shame that analog-style filters were not included as this would had really made it the end-all of romplers. But the technology of 1987 had not advanced yet to provide digital filtering in economical form - that had to wait until 1992 when the K2000 was released. While the new models were impressive, I had too much work invested with the older 1000 to abandon them and did not want to convert all my work, and there was really no overwhelming feature to justify the upgrade. And the K2000 and succeeding models used a new sample library so I didn't want to A/B old vs new on a molecular level - too much work.

Reliability wise, my 1000 modules have been very little trouble. With age some problems will need addressing:

One problem that did creep up is a design error in the power supply. The PC board trace carrying the (+)5VDC raw secondary to the rectifier has too little copper/in² around the interconnect pin from the transformer which resulted in gradual burning of the copper trace. Eventually the copper was no longer a conductor and I had to jumper it with 18ga wire. This had to be done on all my modules and seems to be a common problem from discussion forums. There have also been reports of failing LCD and/or relays on the audio outputs but none of my units had those problems.
The backup battery on the power supply board is past its expiration date. It is recharged while the unit is turned on, but with age the battery drains faster when the unit is turned off. When that happens, the unit loses its user memory (patches, settings, etc) and your unit may not boot up. Replacing the battery is not recommended for a novice, but it is an easy job for a competent tech and does not take long to install a new battery. A battery holder is highly recommended for the replacement.
The backlight on the LCD display fades with age, eventually to the point it is hard to read. Modern replacements can be found that are direct drop-in replacement. Information can be found online which can be shared with a competent tech. I highly recommend the OLED displays, which are much easier to read and are available in different font colors (I liked yellow).
While I was playing in my studio one night,I smelled smoke and immediately turned off power to the studio. The culprit was traced to the P1 connector on the power supply board of one of my Kurzweil 1000 units. If your 1000 unit has trouble booting up when you turn it on, you may have this problem. Early models had tin plated contacts installed in the connector housing for P1 - these contacts are underspec'd for maximum current rating of the ground side of the (+)5VDC rail. The current scorches the tin plating, which turns the contact into a resistor, the resistance combined with the high current generates heat, setting up a vicioous cycle which continues to worsen the scorching process. Eventually the high heat damages the P1 housing and the J1 header that it plugs into. When I checked my other Kurzweils I noticed that the P1/J1 interconnects were gold plated and they did not suffer any damage. Further study revealed that the gold plated contacts have a higher current rating than the tin plated variety. These are made by Molex and are still available, and any competent tech can do this work. The header will need to be replaced, as well as the contacts.

All in all, if you're looking for a rompler with really good bread-n-butter sounds it is hard to go wrong with these.

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